Scippy

SCIP

Solving Constraint Integer Programs

Detailed Description

an algebraic expression used for nonlinear constraints and NLPs

Expressions

int SCIPexprGetNUses (SCIP_EXPR *expr)
 
int SCIPexprGetNChildren (SCIP_EXPR *expr)
 
SCIP_EXPR ** SCIPexprGetChildren (SCIP_EXPR *expr)
 
SCIP_EXPRHDLRSCIPexprGetHdlr (SCIP_EXPR *expr)
 
SCIP_EXPRDATASCIPexprGetData (SCIP_EXPR *expr)
 
void SCIPexprSetData (SCIP_EXPR *expr, SCIP_EXPRDATA *exprdata)
 
SCIP_EXPR_OWNERDATASCIPexprGetOwnerData (SCIP_EXPR *expr)
 
SCIP_Real SCIPexprGetEvalValue (SCIP_EXPR *expr)
 
SCIP_Longint SCIPexprGetEvalTag (SCIP_EXPR *expr)
 
SCIP_Real SCIPexprGetDerivative (SCIP_EXPR *expr)
 
SCIP_Real SCIPexprGetDot (SCIP_EXPR *expr)
 
SCIP_Real SCIPexprGetBardot (SCIP_EXPR *expr)
 
SCIP_Longint SCIPexprGetDiffTag (SCIP_EXPR *expr)
 
SCIP_INTERVAL SCIPexprGetActivity (SCIP_EXPR *expr)
 
SCIP_Longint SCIPexprGetActivityTag (SCIP_EXPR *expr)
 
void SCIPexprSetActivity (SCIP_EXPR *expr, SCIP_INTERVAL activity, SCIP_Longint activitytag)
 
SCIP_EXPRCURV SCIPexprGetCurvature (SCIP_EXPR *expr)
 
void SCIPexprSetCurvature (SCIP_EXPR *expr, SCIP_EXPRCURV curvature)
 
SCIP_Bool SCIPexprIsIntegral (SCIP_EXPR *expr)
 
void SCIPexprSetIntegrality (SCIP_EXPR *expr, SCIP_Bool isintegral)
 

Quadratic Expressions

void SCIPexprGetQuadraticData (SCIP_EXPR *expr, SCIP_Real *constant, int *nlinexprs, SCIP_EXPR ***linexprs, SCIP_Real **lincoefs, int *nquadexprs, int *nbilinexprs, SCIP_Real **eigenvalues, SCIP_Real **eigenvectors)
 
void SCIPexprGetQuadraticQuadTerm (SCIP_EXPR *quadexpr, int termidx, SCIP_EXPR **expr, SCIP_Real *lincoef, SCIP_Real *sqrcoef, int *nadjbilin, int **adjbilin, SCIP_EXPR **sqrexpr)
 
void SCIPexprGetQuadraticBilinTerm (SCIP_EXPR *expr, int termidx, SCIP_EXPR **expr1, SCIP_EXPR **expr2, SCIP_Real *coef, int *pos2, SCIP_EXPR **prodexpr)
 
SCIP_Bool SCIPexprAreQuadraticExprsVariables (SCIP_EXPR *expr)
 

Core Expression Handlers

SCIP_VARSCIPgetVarExprVar (SCIP_EXPR *expr)
 
SCIP_Real SCIPgetValueExprValue (SCIP_EXPR *expr)
 
SCIP_RealSCIPgetCoefsExprSum (SCIP_EXPR *expr)
 
SCIP_Real SCIPgetConstantExprSum (SCIP_EXPR *expr)
 
SCIP_Real SCIPgetCoefExprProduct (SCIP_EXPR *expr)
 
SCIP_Real SCIPgetExponentExprPow (SCIP_EXPR *expr)
 

Expression Iterator

More details on the DFS mode: Many algorithms over expression trees need to traverse the tree in depth-first manner and a natural way of implementing these algorithms is by using recursion. In general, a function which traverses the tree in depth-first looks like

fun( expr )
   enterexpr()
   continue skip or abort
      for( child in expr->children )
         visitingchild()
         continue skip or abort
         fun(child, data, proceed)
         visitedchild()
         continue skip or abort
   leaveexpr()

Given that some expressions might be quite deep we provide this functionality in an iterative fashion.

Consider an expression (x*y) + z + log(x-y). The corresponding expression graph is

          [+]
      /    |   \
   [*]     |    [log]
   / \     |      |
  /   \    |     [-]
  |   |    |     / \
 [x] [y]  [z]  [x] [y]

(where [x] and [y] are actually the same expression).

If a pointer to the [+] expression is given as root to this expression, it will iterate the graph in a depth-first manner and stop at various stages.

Thus, for the above expression, the expression are visited in the following order and stages:

  • enterexpr([+])
  • visitingchild([+]), currentchild = 0
  • enterexpr([*])
  • visitingchild([*]), currentchild = 0
  • enterexpr([x])
  • leaveexpr([x])
  • visitedchild([*]), currentchild = 0
  • visitingchild([*]), currentchild = 1
  • enterexpr([y])
  • leaveexpr([y])
  • visitedchild([*]), currentchild = 1
  • leaveexpr([*])
  • visitedchild([+]), currentchild = 0
  • visitingchild([+]), currentchild = 1
  • enterexpr([z])
  • leaveexpr([z])
  • visitedchild([+]), currentchild = 1
  • visitingchild([+]), currentchild = 2
  • enterexpr([log])
  • visitingchild([log]), currentchild = 0
  • enterexpr([-])
  • visitingchild([-]), currentchild = 0
  • enterexpr([x])
  • leaveexpr([x])
  • visitedchild([-]), currentchild = 0
  • visitingchild([-]), currentchild = 1
  • enterexpr([y])
  • leaveexpr([y])
  • visitedchild([-]), currentchild = 1
  • leaveexpr([-])
  • visitedchild([log]), currentchild = 0
  • leaveexpr([log])
  • visitedchild([+]) currentchild = 2
  • leaveexpr([+])

The caller can direct the iterator to skip parts of the tree:

  • If calling SCIPexpriterSkipDFS() in SCIP_EXPRITER_ENTEREXPR stage, all children of that expression will be skipped. The SCIP_EXPRITER_LEAVEEXPR stage will still be next.
  • If calling SCIPexpriterSkipDFS() in SCIP_EXPRITER_VISITINGCHILD stage, visiting the current child will be skipped.
  • If calling SCIPexpriterSkipDFS() in SCIP_EXPRITER_VISITEDCHILD child, visiting the remaining children will be skipped.
SCIP_Bool SCIPexpriterIsInit (SCIP_EXPRITER *iterator)
 
SCIP_RETCODE SCIPexpriterInit (SCIP_EXPRITER *iterator, SCIP_EXPR *expr, SCIP_EXPRITER_TYPE type, SCIP_Bool allowrevisit)
 
SCIP_EXPRSCIPexpriterRestartDFS (SCIP_EXPRITER *iterator, SCIP_EXPR *expr)
 
void SCIPexpriterSetStagesDFS (SCIP_EXPRITER *iterator, SCIP_EXPRITER_STAGE stopstages)
 
SCIP_EXPRSCIPexpriterGetCurrent (SCIP_EXPRITER *iterator)
 
SCIP_EXPRITER_STAGE SCIPexpriterGetStageDFS (SCIP_EXPRITER *iterator)
 
int SCIPexpriterGetChildIdxDFS (SCIP_EXPRITER *iterator)
 
SCIP_EXPRSCIPexpriterGetChildExprDFS (SCIP_EXPRITER *iterator)
 
SCIP_EXPRSCIPexpriterGetParentDFS (SCIP_EXPRITER *iterator)
 
SCIP_EXPRITER_USERDATA SCIPexpriterGetCurrentUserData (SCIP_EXPRITER *iterator)
 
SCIP_EXPRITER_USERDATA SCIPexpriterGetChildUserDataDFS (SCIP_EXPRITER *iterator)
 
SCIP_EXPRITER_USERDATA SCIPexpriterGetExprUserData (SCIP_EXPRITER *iterator, SCIP_EXPR *expr)
 
void SCIPexpriterSetCurrentUserData (SCIP_EXPRITER *iterator, SCIP_EXPRITER_USERDATA userdata)
 
void SCIPexpriterSetExprUserData (SCIP_EXPRITER *iterator, SCIP_EXPR *expr, SCIP_EXPRITER_USERDATA userdata)
 
void SCIPexpriterSetChildUserData (SCIP_EXPRITER *iterator, SCIP_EXPRITER_USERDATA userdata)
 
SCIP_EXPRSCIPexpriterGetNext (SCIP_EXPRITER *iterator)
 
SCIP_EXPRSCIPexpriterSkipDFS (SCIP_EXPRITER *iterator)
 
SCIP_Bool SCIPexpriterIsEnd (SCIP_EXPRITER *iterator)
 

Function Curvature

SCIP_EXPRCURV SCIPexprcurvAdd (SCIP_EXPRCURV curv1, SCIP_EXPRCURV curv2)
 
SCIP_EXPRCURV SCIPexprcurvNegate (SCIP_EXPRCURV curvature)
 
SCIP_EXPRCURV SCIPexprcurvMultiply (SCIP_Real factor, SCIP_EXPRCURV curvature)
 
SCIP_EXPRCURV SCIPexprcurvPower (SCIP_INTERVAL basebounds, SCIP_EXPRCURV basecurv, SCIP_Real exponent)
 
SCIP_EXPRCURV SCIPexprcurvPowerInv (SCIP_INTERVAL basebounds, SCIP_Real exponent, SCIP_EXPRCURV powercurv)
 
SCIP_EXPRCURV SCIPexprcurvMonomial (int nfactors, SCIP_Real *exponents, int *factoridxs, SCIP_EXPRCURV *factorcurv, SCIP_INTERVAL *factorbounds)
 
SCIP_Bool SCIPexprcurvMonomialInv (SCIP_EXPRCURV monomialcurv, int nfactors, SCIP_Real *exponents, SCIP_INTERVAL *factorbounds, SCIP_EXPRCURV *factorcurv)
 
const char * SCIPexprcurvGetName (SCIP_EXPRCURV curv)
 

Expressions

SCIP_RETCODE SCIPcreateExpr (SCIP *scip, SCIP_EXPR **expr, SCIP_EXPRHDLR *exprhdlr, SCIP_EXPRDATA *exprdata, int nchildren, SCIP_EXPR **children, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPcreateExpr2 (SCIP *scip, SCIP_EXPR **expr, SCIP_EXPRHDLR *exprhdlr, SCIP_EXPRDATA *exprdata, SCIP_EXPR *child1, SCIP_EXPR *child2, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPcreateExprQuadratic (SCIP *scip, SCIP_EXPR **expr, int nlinvars, SCIP_VAR **linvars, SCIP_Real *lincoefs, int nquadterms, SCIP_VAR **quadvars1, SCIP_VAR **quadvars2, SCIP_Real *quadcoefs, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPcreateExprMonomial (SCIP *scip, SCIP_EXPR **expr, int nfactors, SCIP_VAR **vars, SCIP_Real *exponents, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPappendExprChild (SCIP *scip, SCIP_EXPR *expr, SCIP_EXPR *child)
 
SCIP_RETCODE SCIPreplaceExprChild (SCIP *scip, SCIP_EXPR *expr, int childidx, SCIP_EXPR *newchild)
 
SCIP_RETCODE SCIPremoveExprChildren (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPduplicateExpr (SCIP *scip, SCIP_EXPR *expr, SCIP_EXPR **copyexpr, SCIP_DECL_EXPR_MAPEXPR((*mapexpr)), void *mapexprdata, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPduplicateExprShallow (SCIP *scip, SCIP_EXPR *expr, SCIP_EXPR **copyexpr, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPcopyExpr (SCIP *sourcescip, SCIP *targetscip, SCIP_EXPR *expr, SCIP_EXPR **copyexpr, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata, SCIP_HASHMAP *varmap, SCIP_HASHMAP *consmap, SCIP_Bool global, SCIP_Bool *valid)
 
SCIP_RETCODE SCIPparseExpr (SCIP *scip, SCIP_EXPR **expr, const char *exprstr, const char **finalpos, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
void SCIPcaptureExpr (SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPreleaseExpr (SCIP *scip, SCIP_EXPR **expr)
 
SCIP_Bool SCIPisExprVar (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_Bool SCIPisExprValue (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_Bool SCIPisExprSum (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_Bool SCIPisExprProduct (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_Bool SCIPisExprPower (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPprintExpr (SCIP *scip, SCIP_EXPR *expr, FILE *file)
 
SCIP_RETCODE SCIPprintExprDotInit (SCIP *scip, SCIP_EXPRPRINTDATA **printdata, FILE *file, SCIP_EXPRPRINT_WHAT whattoprint)
 
SCIP_RETCODE SCIPprintExprDotInit2 (SCIP *scip, SCIP_EXPRPRINTDATA **printdata, const char *filename, SCIP_EXPRPRINT_WHAT whattoprint)
 
SCIP_RETCODE SCIPprintExprDot (SCIP *scip, SCIP_EXPRPRINTDATA *printdata, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPprintExprDotFinal (SCIP *scip, SCIP_EXPRPRINTDATA **printdata)
 
SCIP_RETCODE SCIPshowExpr (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPdismantleExpr (SCIP *scip, FILE *file, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPevalExpr (SCIP *scip, SCIP_EXPR *expr, SCIP_SOL *sol, SCIP_Longint soltag)
 
SCIP_Longint SCIPgetExprNewSoltag (SCIP *scip)
 
SCIP_RETCODE SCIPevalExprActivity (SCIP *scip, SCIP_EXPR *expr)
 
int SCIPcompareExpr (SCIP *scip, SCIP_EXPR *expr1, SCIP_EXPR *expr2)
 
SCIP_RETCODE SCIPhashExpr (SCIP *scip, SCIP_EXPR *expr, unsigned int *hashval)
 
SCIP_RETCODE SCIPsimplifyExpr (SCIP *scip, SCIP_EXPR *rootexpr, SCIP_EXPR **simplified, SCIP_Bool *changed, SCIP_Bool *infeasible, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
 
SCIP_RETCODE SCIPreplaceCommonSubexpressions (SCIP *scip, SCIP_EXPR **exprs, int nexprs, SCIP_Bool *replacedroot)
 
SCIP_RETCODE SCIPcomputeExprCurvature (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPcomputeExprIntegrality (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPgetExprNVars (SCIP *scip, SCIP_EXPR *expr, int *nvars)
 
SCIP_RETCODE SCIPgetExprVarExprs (SCIP *scip, SCIP_EXPR *expr, SCIP_EXPR **varexprs, int *nvarexprs)
 

Differentiation

Gradients (Automatic differentiation Backward mode)

Given a function, say, \(f(s(x,y),t(x,y))\) there is a common mnemonic technique to compute its partial derivatives, using a tree diagram. Suppose we want to compute the partial derivative of \(f\) w.r.t. \(x\). Write the function as a tree:

f
|-----|
s     t
|--|  |--|
x  y  x  y

The weight of an edge between two nodes represents the partial derivative of the parent w.r.t. the children, e.g.,

f
|
s

is \( \partial_sf \). The weight of a path is the product of the weight of the edges in the path. The partial derivative of \(f\) w.r.t. \(x\) is then the sum of the weights of all paths connecting \(f\) with \(x\):

\[ \frac{\partial f}{\partial x} = \partial_s f \cdot \partial_x s + \partial_t f \cdot \partial_x t. \]

We follow this method in order to compute the gradient of an expression (root) at a given point (point). Note that an expression is a DAG representation of a function, but there is a 1-1 correspondence between paths in the DAG and path in a tree diagram of a function. Initially, we set root->derivative to 1.0. Then, traversing the tree in Depth First (see SCIPexpriterInit), for every expr that has children, we store in its i-th child, child[i]->derivative, the derivative of expr w.r.t. child evaluated at point multiplied with expr->derivative.

For example:

  1. f->derivative = 1.0
  2. s->derivative = \(\partial_s f \,\cdot\) f->derivative = \(\partial_s f\)
  3. x->derivative = \(\partial_x s \,\cdot\) s->derivative = \(\partial_x s \cdot \partial_s f\)

However, when the child is a variable expressions, we actually need to initialize child->derivative to 0.0 and afterwards add, instead of overwrite the computed value. The complete example would then be:

  1. f->derivative = 1.0, x->derivative = 0.0, y->derivative = 0.0
  2. s->derivative = \(\partial_s f \,\cdot\) f->derivative = \(\partial_s f\)
  3. x->derivative += \(\partial_x s \,\cdot\) s->derivative = \(\partial_x s \cdot \partial_s f\)
  4. y->derivative += \(\partial_y s \,\cdot\) s->derivative = \(\partial_y s \cdot \partial_s f\)
  5. t->derivative = \(\partial_t f \,\cdot\) f->derivative = \(\partial_t f\)
  6. x->derivative += \(\partial_x t \,\cdot\) t->derivative = \(\partial_x t \cdot \partial_t f\)
  7. y->derivative += \(\partial_y t \,\cdot\) t->derivative = \(\partial_y t \cdot \partial_t f\)

Note that, to compute this, we only need to know, for each expression, its partial derivatives w.r.t a given child at a point. This is what the callback SCIP_DECL_EXPRBWDIFF should return. Indeed, from "derivative of expr w.r.t. child evaluated at point multiplied with expr->derivative", note that at the moment of processing a child, we already know expr->derivative, so the only missing piece of information is "the derivative of expr w.r.t. child evaluated at point".

An equivalent way of interpreting the procedure is that expr->derivative stores the derivative of the root w.r.t. expr. This way, x->derivative and y->derivative will contain the partial derivatives of root w.r.t. the variable, that is, the gradient. Note, however, that this analogy is only correct for leave expressions, since the derivative value of an intermediate expression gets overwritten.

Hessian (Automatic differentiation Backward on Forward mode)

Computing the Hessian is more complicated since it is the derivative of the gradient, which is a function with more than one output. We compute the Hessian by computing "directions" of the Hessian, that is \(H\cdot u\) for different \(u\). This is easy in general, since it is the gradient of the scalar function \(\nabla f u\), that is, the directional derivative of \(f\) in the direction \(u\): \(D_u f\).

This is easily computed via the so called forward mode. Just as expr->derivative stores the partial derivative of the root w.r.t. expr, expr->dot stores the directional derivative of expr in the direction \(u\). Then, by the chain rule, expr->dot = \(\sum_{c:\text{children}} \partial_c \text{expr} \,\cdot\) c->dot.

Starting with x[i]->dot = \(u_i\), we can compute expr->dot for every expression at the same time we evaluate expr. Computing expr->dot is the purpose of the callback SCIP_DECL_EXPRFWDIFF. Obviously, when this callback is called, the "dots" of all children are known (just like evaluation, where the value of all children are known).

Once we have this information, we compute the gradient of this function, following the same idea as before. We define expr->bardot to be the directional derivative in direction \(u\) of the partial derivative of the root w.r.t expr, that is \(D_u (\partial_{\text{expr}} f) = D_u\) (expr->derivative).

This way, x[i]->bardot = \(D_u (\partial_{x_i} f) = e_i^T H_f u\). Hence vars->bardot contain \(H_f u\). By the chain rule, product rule, and definition we have

\begin{eqnarray*} \texttt{expr->bardot} & = & D_u (\partial_{\text{expr}} f) \\ & = & D_u ( \partial_{\text{parent}} f \cdot \partial_{\text{expr}} \text{parent} ) \\ & = & D_u ( \texttt{parent->derivative} \cdot \partial_{\text{expr}} \text{parent} ) \\ & = & \partial_{\text{expr}} \text{parent} \cdot D_u (\texttt{parent->derivative}) + \texttt{parent->derivative} \cdot D_u (\partial_{\text{expr}} \text{parent}) \\ & = & \texttt{parent->bardot} \cdot \partial_{\text{expr}} \text{parent} + \texttt{parent->derivative} \cdot D_u (\partial_{\text{expr}} \text{parent}) \end{eqnarray*}

Note that we have computed parent->bardot and parent->derivative at this point, while \(\partial_{\text{expr}} \text{parent}\) is the return of SCIP_DECL_EXPRBWDIFF. Hence the only information we need to compute is \(D_u (\partial_{\text{expr}} \text{parent})\). This is the purpose of the callback SCIP_DECL_EXPRBWFWDIFF.

SCIP_RETCODE SCIPevalExprGradient (SCIP *scip, SCIP_EXPR *expr, SCIP_SOL *sol, SCIP_Longint soltag)
 
SCIP_RETCODE SCIPevalExprHessianDir (SCIP *scip, SCIP_EXPR *expr, SCIP_SOL *sol, SCIP_Longint soltag, SCIP_SOL *direction)
 

Expression Handler Callbacks

 SCIP_DECL_EXPRCURVATURE (SCIPcallExprCurvature)
 
 SCIP_DECL_EXPRMONOTONICITY (SCIPcallExprMonotonicity)
 
SCIP_RETCODE SCIPcallExprEval (SCIP *scip, SCIP_EXPR *expr, SCIP_Real *childrenvalues, SCIP_Real *val)
 
SCIP_RETCODE SCIPcallExprEvalFwdiff (SCIP *scip, SCIP_EXPR *expr, SCIP_Real *childrenvalues, SCIP_Real *direction, SCIP_Real *val, SCIP_Real *dot)
 
 SCIP_DECL_EXPRINTEVAL (SCIPcallExprInteval)
 
 SCIP_DECL_EXPRESTIMATE (SCIPcallExprEstimate)
 
 SCIP_DECL_EXPRINITESTIMATES (SCIPcallExprInitestimates)
 
 SCIP_DECL_EXPRSIMPLIFY (SCIPcallExprSimplify)
 
 SCIP_DECL_EXPRREVERSEPROP (SCIPcallExprReverseprop)
 

Expression Iterator

SCIP_RETCODE SCIPcreateExpriter (SCIP *scip, SCIP_EXPRITER **iterator)
 
void SCIPfreeExpriter (SCIP_EXPRITER **iterator)
 

Quadratic Expressions

SCIP_RETCODE SCIPcheckExprQuadratic (SCIP *scip, SCIP_EXPR *expr, SCIP_Bool *isquadratic)
 
void SCIPfreeExprQuadratic (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_Real SCIPevalExprQuadratic (SCIP *scip, SCIP_EXPR *expr, SCIP_SOL *sol)
 
SCIP_RETCODE SCIPprintExprQuadratic (SCIP *scip, SCIP_EXPR *expr)
 
SCIP_RETCODE SCIPcomputeExprQuadraticCurvature (SCIP *scip, SCIP_EXPR *expr, SCIP_EXPRCURV *curv, SCIP_HASHMAP *assumevarfixed, SCIP_Bool storeeigeninfo)
 

Function Documentation

◆ SCIPexprGetNUses()

int SCIPexprGetNUses ( SCIP_EXPR expr)

gets the number of times the expression is currently captured

Parameters
exprexpression

Definition at line 3788 of file expr.c.

References NULL, and SCIP_Expr::nuses.

Referenced by enforceSP12(), SCIPaddExprNonlinear(), and SCIPaddLinearVarNonlinear().

◆ SCIPexprGetNChildren()

int SCIPexprGetNChildren ( SCIP_EXPR expr)

gives the number of children of an expression

Parameters
exprexpression

Definition at line 3798 of file expr.c.

References SCIP_Expr::nchildren, and NULL.

Referenced by atomic_userexpr::atomic_userexpr(), bilinboundGetX(), bilinearTermsInsertAll(), buildQuadExprMatrix(), checkAndCollectQuadratic(), collectLeafs(), computeEstimatorsTrig(), computeInitialCutsTrig(), computeSymmetryGroup(), constructExpr(), createNlhdlrExprData(), createNlRow(), DECL_CURVCHECK(), detectExpr(), detectMinors(), detectSocNorm(), detectSocQuadraticComplex(), detectSocQuadraticSimple(), doBfsNext(), doReverseTopologicalNext(), enforceSP11(), enforceSP12(), eval(), evalExprInAux(), exprIsMultivarLinear(), exprIsSemicontinuous(), fillGraphByNonlinearConss(), findUnlockedLinearVar(), forbidNonlinearVariablesMultiaggration(), forwardPropExpr(), getBilinearBinaryTerms(), getBinaryProductExpr(), getBinaryProductExprDo(), getExprSize(), getFactorizedBinaryQuadraticExpr(), getFeasiblePointsBilinear(), hashExpr(), intevalBilinear(), isBinaryProduct(), isPackingCons(), nlhdlrExprCreate(), nlhdlrExprGrowChildren(), presolveImplint(), presolveSingleLockedVars(), printRow(), printSOSCons(), propagateLocks(), readConstraints(), readObjective(), replaceBinaryProducts(), reversePropBilinear(), reversePropQueue(), scaleConsSides(), SCIP_DECL_EXPRBWDIFF(), SCIP_DECL_EXPRBWFWDIFF(), SCIP_DECL_EXPRCOMPARE(), SCIP_DECL_EXPRCOPYDATA(), SCIP_DECL_EXPRCURVATURE(), SCIP_DECL_EXPRESTIMATE(), SCIP_DECL_EXPREVAL(), SCIP_DECL_EXPRFWDIFF(), SCIP_DECL_EXPRHASH(), SCIP_DECL_EXPRINITESTIMATES(), SCIP_DECL_EXPRINTEGRALITY(), SCIP_DECL_EXPRINTEVAL(), SCIP_DECL_EXPRMONOTONICITY(), SCIP_DECL_EXPRREVERSEPROP(), SCIP_DECL_EXPRSIMPLIFY(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLRESTIMATE(), SCIP_DECL_NLHDLREVALAUX(), SCIP_DECL_NLHDLRINITSEPA(), SCIP_DECL_NLHDLRREVERSEPROP(), SCIPaddIneqBilinear(), SCIPappendExprSumExpr(), SCIPcomputeExprCurvature(), SCIPcomputeExprIntegrality(), SCIPexprCheckQuadratic(), SCIPexprintCompile(), SCIPisExprVaridx(), SCIPmultiplyByConstantExprSum(), SCIPregisterExprUsageNonlinear(), SCIPtightenExprIntervalNonlinear(), simplifyFactor(), simplifyTerm(), and transformExpr().

◆ SCIPexprGetChildren()

SCIP_EXPR** SCIPexprGetChildren ( SCIP_EXPR expr)

gives the children of an expression (can be NULL if no children)

Parameters
exprexpression

Definition at line 3808 of file expr.c.

References SCIP_Expr::children, and NULL.

Referenced by bilinboundGetX(), bilinearTermsInsertAll(), buildQuadExprMatrix(), checkAndCollectQuadratic(), constructExpr(), createNlhdlrExprData(), createNlRow(), DECL_CURVCHECK(), detectExpr(), detectMinors(), detectSocNorm(), detectSocQuadraticSimple(), doBfsNext(), doReverseTopologicalNext(), enforceSP11(), enforceSP12(), eval(), evalExprInAux(), exprIsMultivarLinear(), exprIsSemicontinuous(), findUnlockedLinearVar(), forbidNonlinearVariablesMultiaggration(), getBilinearBinaryTerms(), getBinaryProductExpr(), getBinaryProductExprDo(), getExprSize(), getFactorizedBinaryQuadraticExpr(), getFeasiblePointsBilinear(), hashExpr(), intevalBilinear(), isBinaryProduct(), isPackingCons(), mergeProductExprlist(), nlhdlrExprGrowChildren(), presolveImplint(), presolveSingleLockedVars(), printRow(), printSOSCons(), readConstraints(), readObjective(), reversePropBilinear(), reversePropQueue(), scaleConsSides(), SCIP_DECL_EXPRBWDIFF(), SCIP_DECL_EXPRBWFWDIFF(), SCIP_DECL_EXPRCOMPARE(), SCIP_DECL_EXPRCURVATURE(), SCIP_DECL_EXPRESTIMATE(), SCIP_DECL_EXPREVAL(), SCIP_DECL_EXPRFWDIFF(), SCIP_DECL_EXPRINITESTIMATES(), SCIP_DECL_EXPRINTEGRALITY(), SCIP_DECL_EXPRINTEVAL(), SCIP_DECL_EXPRMONOTONICITY(), SCIP_DECL_EXPRSIMPLIFY(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLRESTIMATE(), SCIP_DECL_NLHDLREVALAUX(), SCIP_DECL_NLHDLRINITSEPA(), SCIP_DECL_NLHDLRREVERSEPROP(), SCIPaddIneqBilinear(), SCIPcomputeExprCurvature(), SCIPexprCheckQuadratic(), SCIPexprintCompile(), simplifyFactor(), simplifyTerm(), and transformExpr().

◆ SCIPexprGetHdlr()

◆ SCIPexprGetData()

◆ SCIPexprSetData()

void SCIPexprSetData ( SCIP_EXPR expr,
SCIP_EXPRDATA exprdata 
)

sets the expression data of an expression

The pointer to possible old data is overwritten and the freedata-callback is not called before. This function is intended to be used by expression handler only.

Parameters
exprexpression
exprdataexpression data to be set (can be NULL)

Definition at line 3846 of file expr.c.

References SCIP_Expr::exprdata, SCIP_Expr::exprhdlr, and NULL.

Referenced by SCIP_DECL_EXPRFREEDATA(), and SCIPsetIndexExprVaridx().

◆ SCIPexprGetOwnerData()

◆ SCIPexprGetEvalValue()

◆ SCIPexprGetEvalTag()

SCIP_Longint SCIPexprGetEvalTag ( SCIP_EXPR expr)

gives the evaluation tag from the last evaluation, or 0

See also
SCIPevalExpr
Parameters
exprexpression

Definition at line 3885 of file expr.c.

References SCIP_Expr::evaltag, and NULL.

Referenced by addTightEstimatorCuts().

◆ SCIPexprGetDerivative()

SCIP_Real SCIPexprGetDerivative ( SCIP_EXPR expr)

returns the derivative stored in an expression (or SCIP_INVALID if there was an evaluation error)

See also
SCIPevalExprGradient
Parameters
exprexpression

Definition at line 3898 of file expr.c.

References SCIP_Expr::derivative, and NULL.

Referenced by computeGradient(), estimateGradient(), generateCut(), getConsRelViolation(), SCIPaddNlRowGradientBenderscutOpt(), and SCIPgetExprPartialDiffNonlinear().

◆ SCIPexprGetDot()

SCIP_Real SCIPexprGetDot ( SCIP_EXPR expr)

gives the value of directional derivative from the last evaluation of a directional derivative of expression (or SCIP_INVALID if there was an error)

See also
SCIPevalExprHessianDir
Parameters
exprexpression

Definition at line 3912 of file expr.c.

References SCIP_Expr::dot, and NULL.

Referenced by SCIP_DECL_EXPRBWFWDIFF(), and SCIP_DECL_EXPRFWDIFF().

◆ SCIPexprGetBardot()

SCIP_Real SCIPexprGetBardot ( SCIP_EXPR expr)

gives the value of directional derivative from the last evaluation of a directional derivative of derivative of root (or SCIP_INVALID if there was an error)

See also
SCIPevalExprHessianDir
Parameters
exprexpression

Definition at line 3926 of file expr.c.

References SCIP_Expr::bardot, and NULL.

Referenced by SCIPgetExprPartialDiffGradientDirNonlinear().

◆ SCIPexprGetDiffTag()

SCIP_Longint SCIPexprGetDiffTag ( SCIP_EXPR expr)

returns the difftag stored in an expression

can be used to check whether partial derivative value is valid

See also
SCIPevalExprGradient
Parameters
exprexpression

Definition at line 3941 of file expr.c.

References SCIP_Expr::difftag, and NULL.

Referenced by estimateGradient(), getConsRelViolation(), SCIPgetExprPartialDiffGradientDirNonlinear(), and SCIPgetExprPartialDiffNonlinear().

◆ SCIPexprGetActivity()

◆ SCIPexprGetActivityTag()

SCIP_Longint SCIPexprGetActivityTag ( SCIP_EXPR expr)

returns the tag associated with the activity of the expression

It can depend on the owner of the expression how to interpret this tag. SCIPevalExprActivity() compares with stat->domchgcount.

See also
SCIPevalExprActivity
Parameters
exprexpression

Definition at line 3970 of file expr.c.

References SCIP_Expr::activitytag, and NULL.

Referenced by catchVarEvents(), createAuxVar(), deinitSolve(), forwardPropExpr(), presolveRedundantConss(), SCIP_DECL_EXPR_OWNEREVALACTIVITY(), SCIP_DECL_NLHDLRREVERSEPROP(), SCIPgetExprBoundsNonlinear(), and SCIPtightenExprIntervalNonlinear().

◆ SCIPexprSetActivity()

void SCIPexprSetActivity ( SCIP_EXPR expr,
SCIP_INTERVAL  activity,
SCIP_Longint  activitytag 
)

set the activity with tag for an expression

Parameters
exprexpression
activitynew activity
activitytagtag associated with activity

Definition at line 3980 of file expr.c.

References SCIP_Expr::activity, SCIP_Expr::activitytag, and NULL.

Referenced by catchVarEvents(), forwardPropExpr(), and SCIP_DECL_EVENTEXEC().

◆ SCIPexprGetCurvature()

SCIP_EXPRCURV SCIPexprGetCurvature ( SCIP_EXPR expr)

returns the curvature of an expression

Note
Call SCIPcomputeExprCurvature() before calling this function.
Parameters
exprexpression

Definition at line 3996 of file expr.c.

References SCIP_Expr::curvature, and NULL.

Referenced by constructExpr(), createNlhdlrExprData(), DECL_CURVCHECK(), estimateVertexPolyhedral(), SCIP_DECL_NLHDLRESTIMATE(), SCIP_DECL_NLHDLRINITSEPA(), and SCIPcomputeExprCurvature().

◆ SCIPexprSetCurvature()

void SCIPexprSetCurvature ( SCIP_EXPR expr,
SCIP_EXPRCURV  curvature 
)

sets the curvature of an expression

Parameters
exprexpression
curvaturecurvature of the expression

Definition at line 4006 of file expr.c.

References SCIP_Expr::curvature, and NULL.

Referenced by createNlhdlrExprData(), DECL_CURVCHECK(), nlhdlrExprCreate(), SCIP_DECL_NLHDLRDETECT(), and SCIPcomputeExprCurvature().

◆ SCIPexprIsIntegral()

SCIP_Bool SCIPexprIsIntegral ( SCIP_EXPR expr)

returns whether an expression is integral

Parameters
exprexpression

Definition at line 4017 of file expr.c.

References SCIP_Expr::isintegral, and NULL.

Referenced by createAuxVar(), forwardPropExpr(), presolveImplint(), SCIP_DECL_EXPRESTIMATE(), SCIP_DECL_EXPRINITESTIMATES(), SCIP_DECL_EXPRINTEGRALITY(), SCIP_DECL_NLHDLRESTIMATE(), and SCIPtightenExprIntervalNonlinear().

◆ SCIPexprSetIntegrality()

void SCIPexprSetIntegrality ( SCIP_EXPR expr,
SCIP_Bool  isintegral 
)

sets the integrality flag of an expression

Parameters
exprexpression
isintegralintegrality of the expression

Definition at line 4027 of file expr.c.

References SCIP_Expr::isintegral, and NULL.

Referenced by presolveImplint(), and SCIPcomputeExprIntegrality().

◆ SCIPexprGetQuadraticData()

void SCIPexprGetQuadraticData ( SCIP_EXPR expr,
SCIP_Real constant,
int *  nlinexprs,
SCIP_EXPR ***  linexprs,
SCIP_Real **  lincoefs,
int *  nquadexprs,
int *  nbilinexprs,
SCIP_Real **  eigenvalues,
SCIP_Real **  eigenvectors 
)

gives the coefficients and expressions that define a quadratic expression

It can return the constant part, the number, arguments, and coefficients of the purely linear part and the number of quadratic terms and bilinear terms. Note that for arguments that appear in the quadratic part, a linear coefficient is stored with the quadratic term. Use SCIPexprGetQuadraticQuadTerm() and SCIPexprGetQuadraticBilinTerm() to access the data for a quadratic or bilinear term.

It can also return the eigenvalues and the eigenvectors of the matrix \(Q\) when the quadratic is written as \(x^T Q x + b^T x + c^T y + d\), where \(c^T y\) defines the purely linear part. Note, however, that to have access to them one needs to call SCIPcomputeExprQuadraticCurvature() with storeeigeninfo=TRUE. If the eigen information was not stored or it failed to be computed, eigenvalues and eigenvectors will be set to NULL.

This function returns pointers to internal data in linexprs and lincoefs. The user must not change this data.

Parameters
exprquadratic expression
constantbuffer to store constant term, or NULL
nlinexprsbuffer to store number of expressions that appear linearly, or NULL
linexprsbuffer to store pointer to array of expressions that appear linearly, or NULL
lincoefsbuffer to store pointer to array of coefficients of expressions that appear linearly, or NULL
nquadexprsbuffer to store number of expressions in quadratic terms, or NULL
nbilinexprsbuffer to store number of bilinear expressions terms, or NULL
eigenvaluesbuffer to store pointer to array of eigenvalues of Q, or NULL
eigenvectorsbuffer to store pointer to array of eigenvectors of Q, or NULL

Definition at line 4055 of file expr.c.

References SCIP_QuadExpr::constant, SCIP_QuadExpr::eigenvalues, SCIP_QuadExpr::eigenvectors, SCIP_QuadExpr::lincoefs, SCIP_QuadExpr::linexprs, SCIP_QuadExpr::nbilinexprterms, SCIP_QuadExpr::nlinexprs, SCIP_QuadExpr::nquadexprs, NULL, and SCIP_Expr::quaddata.

Referenced by checkConsQuadraticProblem(), computeRestrictionToRay(), computeWRayLinear(), constructLPPos2ConsPosMap(), countBasicVars(), createMIP(), createTcliqueGraph(), DECL_CURVCHECK(), doSeachEcAggr(), findAndStoreEcAggregations(), findVertexAndGetRays(), generateIntercut(), intercutsComputeCommonQuantities(), isCandidate(), isPropagable(), isQuadConsViolated(), nlrowaggrCreate(), presolveAddKKTQuadBilinearTerms(), presolveAddKKTQuadLinearTerms(), presolveAddKKTQuadQuadraticTerms(), printRow(), processNlRow(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLRENFO(), SCIP_DECL_NLHDLREVALAUX(), SCIP_DECL_NLHDLRFREEEXPRDATA(), SCIP_DECL_NLHDLRINTEVAL(), SCIP_DECL_NLHDLRREVERSEPROP(), SCIPevalExprQuadratic(), SCIPevalExprQuadraticAuxNonlinear(), SCIPprintExprQuadratic(), SCIPwriteMps(), searchEcAggrWithCliques(), storeAggrFromMIP(), storeDenseTableauRowsByColumns(), and updateMIP().

◆ SCIPexprGetQuadraticQuadTerm()

void SCIPexprGetQuadraticQuadTerm ( SCIP_EXPR quadexpr,
int  termidx,
SCIP_EXPR **  expr,
SCIP_Real lincoef,
SCIP_Real sqrcoef,
int *  nadjbilin,
int **  adjbilin,
SCIP_EXPR **  sqrexpr 
)

gives the data of a quadratic expression term

For a term \(a \cdot \text{expr}^2 + b \cdot \text{expr} + \sum_i (c_i \cdot \text{expr} \cdot \text{otherexpr}_i)\), returns expr, \(a\), \(b\), the number of summands, and indices of bilinear terms in the quadratic expressions bilinexprterms.

This function returns pointers to internal data in adjbilin. The user must not change this data.

Parameters
quadexprquadratic expression
termidxindex of quadratic term
exprbuffer to store pointer to argument expression (the 'x') of this term, or NULL
lincoefbuffer to store linear coefficient of variable, or NULL
sqrcoefbuffer to store square coefficient of variable, or NULL
nadjbilinbuffer to store number of bilinear terms this variable is involved in, or NULL
adjbilinbuffer to store pointer to indices of associated bilinear terms, or NULL
sqrexprbuffer to store pointer to square expression (the 'x^2') of this term or NULL if no square expression, or NULL

Definition at line 4102 of file expr.c.

References SCIP_QuadExpr_QuadTerm::adjbilin, SCIP_QuadExpr_QuadTerm::expr, SCIP_QuadExpr_QuadTerm::lincoef, SCIP_QuadExpr_QuadTerm::nadjbilin, NULL, SCIP_Expr::quaddata, SCIP_QuadExpr::quadexprterms, SCIP_QuadExpr_QuadTerm::sqrcoef, and SCIP_QuadExpr_QuadTerm::sqrexpr.

Referenced by constructLPPos2ConsPosMap(), countBasicVars(), createMIP(), createTcliqueGraph(), DECL_CURVCHECK(), doSeachEcAggr(), findVertexAndGetRays(), intercutsComputeCommonQuantities(), isCandidate(), isPropagable(), isPropagableTerm(), isQuadConsViolated(), nlrowaggrCreate(), presolveAddKKTQuadLinearTerms(), presolveAddKKTQuadQuadraticTerms(), printRow(), processNlRow(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLREVALAUX(), SCIP_DECL_NLHDLRINTEVAL(), SCIP_DECL_NLHDLRREVERSEPROP(), SCIPevalExprQuadratic(), SCIPevalExprQuadraticAuxNonlinear(), SCIPprintExprQuadratic(), SCIPwriteMps(), searchEcAggrWithCliques(), storeAggrFromMIP(), storeDenseTableauRowsByColumns(), and updateMIP().

◆ SCIPexprGetQuadraticBilinTerm()

void SCIPexprGetQuadraticBilinTerm ( SCIP_EXPR expr,
int  termidx,
SCIP_EXPR **  expr1,
SCIP_EXPR **  expr2,
SCIP_Real coef,
int *  pos2,
SCIP_EXPR **  prodexpr 
)

gives the data of a bilinear expression term

For a term a*expr1*expr2, returns expr1, expr2, a, and the position of the quadratic expression term that uses expr2 in the quadratic expressions quadexprterms.

Parameters
exprquadratic expression
termidxindex of bilinear term
expr1buffer to store first factor, or NULL
expr2buffer to store second factor, or NULL
coefbuffer to coefficient, or NULL
pos2buffer to position of expr2 in quadexprterms array of quadratic expression, or NULL
prodexprbuffer to store pointer to expression that is product if first and second factor, or NULL

Definition at line 4145 of file expr.c.

References SCIP_QuadExpr::bilinexprterms, SCIP_QuadExpr_BilinTerm::coef, SCIP_QuadExpr_BilinTerm::expr1, SCIP_QuadExpr_BilinTerm::expr2, NULL, SCIP_QuadExpr_BilinTerm::pos2, SCIP_QuadExpr_BilinTerm::prodexpr, and SCIP_Expr::quaddata.

Referenced by createMIP(), createTcliqueGraph(), isCandidate(), isQuadConsViolated(), nlrowaggrCreate(), presolveAddKKTQuadBilinearTerms(), printRow(), processNlRow(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLREVALAUX(), SCIP_DECL_NLHDLRINTEVAL(), SCIP_DECL_NLHDLRREVERSEPROP(), SCIPevalExprQuadratic(), SCIPevalExprQuadraticAuxNonlinear(), SCIPprintExprQuadratic(), SCIPwriteMps(), searchEcAggrWithCliques(), storeAggrFromMIP(), and updateMIP().

◆ SCIPexprAreQuadraticExprsVariables()

SCIP_Bool SCIPexprAreQuadraticExprsVariables ( SCIP_EXPR expr)

returns whether all expressions that are used in a quadratic expression are variable expressions

Returns
TRUE iff all linexprs and quadexprterms[.].expr are variable expressions
Parameters
exprquadratic expression

Definition at line 4183 of file expr.c.

References SCIP_QuadExpr::allexprsarevars, NULL, and SCIP_Expr::quaddata.

Referenced by isCandidate(), processNlRow(), SCIP_DECL_NLHDLRDETECT(), and SCIPcheckQuadraticNonlinear().

◆ SCIPgetVarExprVar()

SCIP_VAR* SCIPgetVarExprVar ( SCIP_EXPR expr)

gets the variable of a variable expression

Parameters
exprvariable expression

Definition at line 403 of file expr_var.c.

References EXPRHDLR_NAME, NULL, SCIPexprGetData(), SCIPexprGetHdlr(), and SCIPexprhdlrGetName().

Referenced by addTightEstimatorCuts(), analyzeViolation(), buildQuadExprMatrix(), catchVarEvent(), catchVarEvents(), checkAndCollectQuadratic(), collectBranchingCandidates(), collectLeafs(), computeGradient(), computeOffValues(), computeSymmetryGroup(), createMIP(), createNlRow(), createTcliqueGraph(), detectSocNorm(), detectSocQuadraticSimple(), doSeachEcAggr(), dropVarEvent(), enforceConstraints(), estimateConvexSecant(), estimateGradient(), estimateVertexPolyhedral(), exprIsSemicontinuous(), fillGraphByNonlinearConss(), findUnlockedLinearVar(), forbidNonlinearVariablesMultiaggration(), forwardPropExpr(), generateCut(), getBilinearBinaryTerms(), getBinaryProductExpr(), getBinaryProductExprDo(), isBinaryProduct(), isCandidate(), isPackingCons(), isSingleLockedCand(), nlpAddNlRows(), nlpDelVarPos(), nlrowaggrCreate(), presolveAddKKTQuadBilinearTerms(), presolveAddKKTQuadLinearTerms(), presolveAddKKTQuadQuadraticTerms(), presolveImplint(), presolveRedundantConss(), presolveSingleLockedVars(), printRow(), processNlRow(), propagateLocks(), readConstraints(), readObjective(), registerBranchingCandidates(), registerBranchingCandidatesAllUnfixed(), SCIP_DECL_CONSACTIVE(), SCIP_DECL_CONSGETVARS(), SCIP_DECL_EXPR_MAPEXPR(), SCIP_DECL_EXPR_OWNERCREATE(), SCIP_DECL_EXPR_OWNERFREE(), SCIP_DECL_EXPRCOMPARE(), SCIP_DECL_EXPRCOPYDATA(), SCIP_DECL_EXPREVAL(), SCIP_DECL_EXPRFWDIFF(), SCIP_DECL_EXPRHASH(), SCIP_DECL_EXPRINTEGRALITY(), SCIP_DECL_EXPRINTEVAL(), SCIP_DECL_EXPRPRINT(), SCIP_DECL_EXPRSIMPLIFY(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLRINITSEPA(), SCIP_DECL_VERTEXPOLYFUN(), SCIPaddNlRowGradientBenderscutOpt(), SCIPevalExprQuadratic(), SCIPexprComputeQuadraticCurvature(), SCIPexprDismantle(), SCIPgetExprAuxVarNonlinear(), SCIPisSOCNonlinear(), SCIPnlpGetVarsNonlinearity(), SCIPnlpHasContinuousNonlinearity(), SCIPwriteMps(), and storeVarExprs().

◆ SCIPgetValueExprValue()

◆ SCIPgetCoefsExprSum()

◆ SCIPgetConstantExprSum()

◆ SCIPgetCoefExprProduct()

◆ SCIPgetExponentExprPow()

◆ SCIPexpriterIsInit()

SCIP_Bool SCIPexpriterIsInit ( SCIP_EXPRITER iterator)

returns whether expression iterator is currently initialized

Parameters
iteratorexpression iterator

Definition at line 475 of file expriter.c.

References SCIP_ExprIter::initialized, and NULL.

◆ SCIPexpriterInit()

SCIP_RETCODE SCIPexpriterInit ( SCIP_EXPRITER iterator,
SCIP_EXPR expr,
SCIP_EXPRITER_TYPE  type,
SCIP_Bool  allowrevisit 
)

initializes an expression iterator

Note
If expr is NULL, then iterator will be set into ended-state (SCIPexpriterIsEnd() is TRUE). Useful if following with SCIPexpriterRestartDFS().

If type is DFS, then stopstages will be set to SCIP_EXPRITER_ENTEREXPR. Use SCIPexpriterSetStagesDFS to change this.

Parameters
iteratorexpression iterator
exprexpression of the iterator, can be NULL
typetype of expression iterator
allowrevisitwhether expression are allowed to be visited more than once

Definition at line 491 of file expriter.c.

References SCIP_ExprIter::curr, deinit(), SCIP_ExprIter::dfsstage, ensureStackSize(), SCIP_Stat::exprlastvisitedtag, SCIP_ExprIter::initialized, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, MINBFSSIZE, MINDFSSIZE, SCIP_Stat::nactiveexpriter, NULL, printBacktraces(), SCIP_ExprIter::queue, reverseTopologicalInsert(), SCIP_CALL, SCIP_EXPRITER_BFS, SCIP_EXPRITER_DFS, SCIP_EXPRITER_ENTEREXPR, SCIP_EXPRITER_MAXNACTIVE, SCIP_EXPRITER_RTOPOLOGIC, SCIP_MAXDEPTHLEVEL, SCIP_OKAY, SCIPerrorMessage, SCIPexpriterGetNext(), SCIPqueueClear(), SCIPqueueCreate(), SCIPqueueInsert(), SCIP_ExprIter::stat, SCIP_ExprIter::stopstages, storeBacktrace, SCIP_Stat::subscipdepth, TRUE, and SCIP_ExprIter::visitedtag.

Referenced by addExprViolScoresAuxVars(), addTightEstimatorCuts(), analyzeViolation(), bilinearTermsInsertAll(), canonicalizeConstraints(), collectBranchingCandidates(), collectLeafs(), computeGradient(), computeOffValues(), computeSymmetryGroup(), constructExpr(), createNlhdlrExprData(), deinitSolve(), detectMinors(), detectNlhdlrs(), enforceConstraints(), evalAndDiff(), exprIsNonSmooth(), exprIsSemicontinuous(), fillGraphByNonlinearConss(), forbidNonlinearVariablesMultiaggration(), forwardPropExpr(), generateCut(), initSepa(), nlpAddNlRows(), nlpDelVarPos(), presolveBinaryProducts(), presolveSingleLockedVars(), processNlRow(), propagateLocks(), propConss(), propExprDomains(), registerBranchingCandidates(), SCIP_DECL_CONSACTIVE(), SCIP_DECL_TABLEOUTPUT(), SCIPaddExprsViolScoreNonlinear(), SCIPaddNlRowGradientBenderscutOpt(), SCIPcomputeExprCurvature(), SCIPcomputeExprIntegrality(), SCIPcreateNlpiProblemFromNlRows(), SCIPexprCopy(), SCIPexprDismantle(), SCIPexprEval(), SCIPexprEvalActivity(), SCIPexprEvalGradient(), SCIPexprEvalHessianDir(), SCIPexprintCompile(), SCIPexprPrint(), SCIPexprPrintDot(), SCIPexprRelease(), SCIPexprSimplify(), SCIPgetExprNVars(), SCIPgetExprVarExprs(), SCIPhashExpr(), SCIPmarkExprPropagateNonlinear(), SCIPnlpGetVarsNonlinearity(), SCIPnlpHasContinuousNonlinearity(), SCIPnlpiOracleDelVarSet(), SCIPnlpiOracleGetJacobianSparsity(), SCIPregisterExprUsageNonlinear(), SCIPreplaceCommonSubexpressions(), and updateVariableCounts().

◆ SCIPexpriterRestartDFS()

SCIP_EXPR* SCIPexpriterRestartDFS ( SCIP_EXPRITER iterator,
SCIP_EXPR expr 
)

restarts an already initialized expression iterator in DFS mode

The expression iterator will continue from the given expression, not revisiting expressions that this iterator has already been visited (if initialized with allowrevisit=FALSE) and giving access to the same iterator specified expression data that may have been set already. Also the stop-stages are not reset.

If revisiting is forbidden and given expr has already been visited, then the iterator will behave as on the end of iteration (SCIPexpriterIsEnd() is TRUE). If the enterexpr stage is not one of the stop stages, then the iterator will be moved forward (SCIPexpriterGetNext() is called).

Returns
The current expression.
Parameters
iteratorexpression iterator
exprexpression of the iterator

Definition at line 620 of file expriter.c.

References SCIP_ExprIter::curr, SCIP_ExprIter::dfsstage, SCIP_ExprIter::initialized, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, NULL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_ENTEREXPR, SCIPexpriterGetNext(), SCIP_ExprIter::stopstages, and SCIP_ExprIter::visitedtag.

Referenced by addTightEstimatorCuts(), analyzeViolation(), bilinearTermsInsertAll(), collectBranchingCandidates(), deinitSolve(), detectMinors(), detectNlhdlrs(), enforceConstraint(), forbidNonlinearVariablesMultiaggration(), hashExpr(), initSepa(), propExprDomains(), registerBranchingCandidates(), removeSingleLockedVars(), replaceBinaryProducts(), SCIPaddExprsViolScoreNonlinear(), SCIPnlpHasContinuousNonlinearity(), and SCIPnlpiOracleGetJacobianSparsity().

◆ SCIPexpriterSetStagesDFS()

void SCIPexpriterSetStagesDFS ( SCIP_EXPRITER iterator,
SCIP_EXPRITER_STAGE  stopstages 
)

◆ SCIPexpriterGetCurrent()

◆ SCIPexpriterGetStageDFS()

SCIP_EXPRITER_STAGE SCIPexpriterGetStageDFS ( SCIP_EXPRITER iterator)

gets the current stage that the expression iterator is in when using DFS

If the iterator has finished (SCIPexpriterIsEnd() is TRUE), then the stage is undefined.

Parameters
iteratorexpression iterator

Definition at line 686 of file expriter.c.

References SCIP_ExprIter::dfsstage, SCIP_ExprIter::itertype, NULL, and SCIP_EXPRITER_DFS.

Referenced by computeSymmetryGroup(), fillGraphByNonlinearConss(), forwardPropExpr(), hashExpr(), propagateLocks(), SCIPexprCopy(), SCIPexprDismantle(), SCIPexprEval(), SCIPexprEvalActivity(), SCIPexprPrint(), SCIPexprRelease(), and SCIPexprSimplify().

◆ SCIPexpriterGetChildIdxDFS()

◆ SCIPexpriterGetChildExprDFS()

◆ SCIPexpriterGetParentDFS()

SCIP_EXPR* SCIPexpriterGetParentDFS ( SCIP_EXPRITER iterator)

gives the parent of the current expression of an expression iteration if in DFS mode

Returns
the expression from which the current expression has been accessed
Parameters
iteratorexpression iterator

Definition at line 730 of file expriter.c.

References SCIP_ExprIter::curr, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, NULL, and SCIP_EXPRITER_DFS.

Referenced by computeSymmetryGroup(), fillGraphByNonlinearConss(), and SCIPexprPrint().

◆ SCIPexpriterGetCurrentUserData()

SCIP_EXPRITER_USERDATA SCIPexpriterGetCurrentUserData ( SCIP_EXPRITER iterator)

gives the iterator specific user data of the current expression

Note
The expression iterator mode must be DFS or another mode with allowrevisit=FALSE
Parameters
iteratorexpression iterator

Definition at line 746 of file expriter.c.

References SCIP_ExprIter::curr, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, and NULL.

Referenced by propagateLocks(), and SCIPexprCopy().

◆ SCIPexpriterGetChildUserDataDFS()

SCIP_EXPRITER_USERDATA SCIPexpriterGetChildUserDataDFS ( SCIP_EXPRITER iterator)

gives the iterator specific user data of the current expressions current child

Note
The expression iterator mode must be in DFS mode and stage SCIP_EXPRITER_VISITINGCHILD or SCIP_EXPRITER_VISITEDCHILD
Parameters
iteratorexpression iterator

Definition at line 761 of file expriter.c.

References SCIP_Expr::children, SCIP_ExprIter::curr, SCIP_ExprIter::dfsstage, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, SCIP_Expr::nchildren, NULL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_VISITEDCHILD, and SCIP_EXPRITER_VISITINGCHILD.

Referenced by SCIPexprCopy(), and SCIPexprSimplify().

◆ SCIPexpriterGetExprUserData()

SCIP_EXPRITER_USERDATA SCIPexpriterGetExprUserData ( SCIP_EXPRITER iterator,
SCIP_EXPR expr 
)

gives the iterator specific user data of a given expression

Note
The expression iterator mode must be DFS or another mode with allowrevisit=FALSE
Parameters
iteratorexpression iterator
exprexpression for which to get the userdata of this iterator

Definition at line 780 of file expriter.c.

References SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, and NULL.

Referenced by hashExpr(), SCIP_DECL_HASHKEYVAL(), SCIPexprCopy(), SCIPexprSimplify(), and SCIPhashExpr().

◆ SCIPexpriterSetCurrentUserData()

void SCIPexpriterSetCurrentUserData ( SCIP_EXPRITER iterator,
SCIP_EXPRITER_USERDATA  userdata 
)

sets the iterator specific user data of the current expression for an expression iteration if in DFS mode

Note
The expression iterator mode must be DFS or another mode with allowrevisit=FALSE
Parameters
iteratorexpression iterator
userdatadata to be stored

Definition at line 796 of file expriter.c.

References SCIP_ExprIter::curr, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, and NULL.

Referenced by hashExpr(), propagateLocks(), SCIPexprCopy(), and SCIPexprSimplify().

◆ SCIPexpriterSetExprUserData()

void SCIPexpriterSetExprUserData ( SCIP_EXPRITER iterator,
SCIP_EXPR expr,
SCIP_EXPRITER_USERDATA  userdata 
)

sets the iterator specific user data of a given expression

Note
The expression iterator mode must be DFS or another mode with allowrevisit=FALSE
Parameters
iteratorexpression iterator
exprexpression where to set iterator data
userdatadata to be stored in current child

Definition at line 812 of file expriter.c.

References SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, and NULL.

◆ SCIPexpriterSetChildUserData()

void SCIPexpriterSetChildUserData ( SCIP_EXPRITER iterator,
SCIP_EXPRITER_USERDATA  userdata 
)

sets the iterator specific user data of the current expressions current child

Note
The expression iterator mode must be in DFS mode and stage SCIP_EXPRITER_VISITINGCHILD or SCIP_EXPRITER_VISITEDCHILD
Parameters
iteratorexpression iterator
userdatadata to be stored in current child

Definition at line 828 of file expriter.c.

References SCIP_Expr::children, SCIP_ExprIter::curr, SCIP_ExprIter::dfsstage, SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, SCIP_Expr::nchildren, NULL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_VISITEDCHILD, and SCIP_EXPRITER_VISITINGCHILD.

Referenced by propagateLocks().

◆ SCIPexpriterGetNext()

SCIP_EXPR* SCIPexpriterGetNext ( SCIP_EXPRITER iterator)

moves the iterator to the next expression according to the mode of the expression iterator

Returns
the next expression, if any, and NULL otherwise
Parameters
iteratorexpression iterator

Definition at line 848 of file expriter.c.

References SCIP_ExprIter::curr, SCIP_ExprIter::dfsstage, doBfsNext(), doDfsNext(), doReverseTopologicalNext(), SCIP_Expr::iterdata, SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, NULL, SCIP_EXPRITER_BFS, SCIP_EXPRITER_DFS, SCIP_EXPRITER_MAXNACTIVE, SCIP_EXPRITER_RTOPOLOGIC, SCIP_ExprIter::stopstages, and SCIP_ExprIter::visitedtag.

Referenced by addExprViolScoresAuxVars(), addTightEstimatorCuts(), analyzeViolation(), bilinearTermsInsertAll(), canonicalizeConstraints(), collectBranchingCandidates(), collectLeafs(), computeGradient(), computeOffValues(), computeSymmetryGroup(), constructExpr(), createNlhdlrExprData(), deinitSolve(), detectMinors(), detectNlhdlrs(), enforceConstraint(), evalAndDiff(), exprIsNonSmooth(), exprIsSemicontinuous(), fillGraphByNonlinearConss(), forbidNonlinearVariablesMultiaggration(), forwardPropExpr(), generateCut(), hashExpr(), initSepa(), nlpAddNlRows(), nlpDelVarPos(), processNlRow(), propagateLocks(), propConss(), propExprDomains(), registerBranchingCandidates(), removeSingleLockedVars(), replaceBinaryProducts(), SCIP_DECL_CONSACTIVE(), SCIP_DECL_TABLEOUTPUT(), SCIPaddExprsViolScoreNonlinear(), SCIPaddNlRowGradientBenderscutOpt(), SCIPcomputeExprCurvature(), SCIPcomputeExprIntegrality(), SCIPcreateNlpiProblemFromNlRows(), SCIPexprCopy(), SCIPexprDismantle(), SCIPexprEval(), SCIPexprEvalActivity(), SCIPexprEvalGradient(), SCIPexprEvalHessianDir(), SCIPexprintCompile(), SCIPexpriterInit(), SCIPexpriterRestartDFS(), SCIPexpriterSetStagesDFS(), SCIPexpriterSkipDFS(), SCIPexprPrint(), SCIPexprPrintDot(), SCIPexprRelease(), SCIPexprSimplify(), SCIPgetExprNVars(), SCIPgetExprVarExprs(), SCIPmarkExprPropagateNonlinear(), SCIPnlpGetVarsNonlinearity(), SCIPnlpHasContinuousNonlinearity(), SCIPnlpiOracleDelVarSet(), SCIPnlpiOracleGetJacobianSparsity(), SCIPregisterExprUsageNonlinear(), SCIPreplaceCommonSubexpressions(), and updateVariableCounts().

◆ SCIPexpriterSkipDFS()

SCIP_EXPR* SCIPexpriterSkipDFS ( SCIP_EXPRITER iterator)

moves a DFS iterator to one of the next expressions

Returns
the next expression, if any, and NULL otherwise
Parameters
iteratorexpression iterator

Definition at line 920 of file expriter.c.

References SCIP_ExprIter::curr, SCIP_ExprIter::dfsstage, doDfsNext(), SCIP_ExprIter::iterindex, SCIP_ExprIter::itertype, NULL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_ENTEREXPR, SCIP_EXPRITER_LEAVEEXPR, SCIP_EXPRITER_VISITEDCHILD, SCIP_EXPRITER_VISITINGCHILD, SCIPABORT, SCIPerrorMessage, SCIPexpriterGetNext(), and SCIP_ExprIter::stopstages.

Referenced by constructExpr(), forwardPropExpr(), SCIPexprCopy(), SCIPexprEval(), SCIPexprEvalActivity(), SCIPexprRelease(), and SCIPreplaceCommonSubexpressions().

◆ SCIPexpriterIsEnd()

SCIP_Bool SCIPexpriterIsEnd ( SCIP_EXPRITER iterator)

returns whether the iterator visited all expressions already

Parameters
iteratorexpression iterator

Definition at line 959 of file expriter.c.

References SCIP_ExprIter::curr, and NULL.

Referenced by addExprViolScoresAuxVars(), addTightEstimatorCuts(), analyzeViolation(), bilinearTermsInsertAll(), canonicalizeConstraints(), collectBranchingCandidates(), collectLeafs(), computeGradient(), computeOffValues(), computeSymmetryGroup(), constructExpr(), createNlhdlrExprData(), deinitSolve(), detectMinors(), detectNlhdlrs(), enforceConstraint(), evalAndDiff(), exprIsNonSmooth(), exprIsSemicontinuous(), fillGraphByNonlinearConss(), forbidNonlinearVariablesMultiaggration(), forwardPropExpr(), generateCut(), hashExpr(), initSepa(), nlpAddNlRows(), nlpDelVarPos(), processNlRow(), propagateLocks(), propConss(), propExprDomains(), registerBranchingCandidates(), removeSingleLockedVars(), replaceBinaryProducts(), SCIP_DECL_CONSACTIVE(), SCIP_DECL_TABLEOUTPUT(), SCIPaddExprsViolScoreNonlinear(), SCIPaddNlRowGradientBenderscutOpt(), SCIPcomputeExprCurvature(), SCIPcomputeExprIntegrality(), SCIPcreateNlpiProblemFromNlRows(), SCIPexprCopy(), SCIPexprDismantle(), SCIPexprEval(), SCIPexprEvalActivity(), SCIPexprEvalGradient(), SCIPexprEvalHessianDir(), SCIPexprintCompile(), SCIPexprPrint(), SCIPexprPrintDot(), SCIPexprRelease(), SCIPexprSimplify(), SCIPgetExprNVars(), SCIPgetExprVarExprs(), SCIPmarkExprPropagateNonlinear(), SCIPnlpGetVarsNonlinearity(), SCIPnlpHasContinuousNonlinearity(), SCIPnlpiOracleDelVarSet(), SCIPnlpiOracleGetJacobianSparsity(), SCIPregisterExprUsageNonlinear(), SCIPreplaceCommonSubexpressions(), and updateVariableCounts().

◆ SCIPexprcurvAdd()

SCIP_EXPRCURV SCIPexprcurvAdd ( SCIP_EXPRCURV  curv1,
SCIP_EXPRCURV  curv2 
)

gives curvature for a sum of two functions with given curvature

Parameters
curv1curvature of first summand
curv2curvature of second summand

Definition at line 43 of file exprcurv.c.

◆ SCIPexprcurvNegate()

SCIP_EXPRCURV SCIPexprcurvNegate ( SCIP_EXPRCURV  curvature)

gives the curvature for the negation of a function with given curvature

Parameters
curvaturecurvature of function

Definition at line 52 of file exprcurv.c.

References SCIP_EXPRCURV_CONCAVE, SCIP_EXPRCURV_CONVEX, SCIP_EXPRCURV_LINEAR, SCIP_EXPRCURV_UNKNOWN, SCIPABORT, and SCIPerrorMessage.

Referenced by SCIP_DECL_EXPRCURVATURE(), SCIPexprcurvMonomial(), SCIPexprcurvMonomialInv(), and SCIPexprcurvMultiply().

◆ SCIPexprcurvMultiply()

SCIP_EXPRCURV SCIPexprcurvMultiply ( SCIP_Real  factor,
SCIP_EXPRCURV  curvature 
)

gives curvature for a functions with given curvature multiplied by a constant factor

Parameters
factorconstant factor
curvaturecurvature of other factor

Definition at line 78 of file exprcurv.c.

References SCIP_EXPRCURV_LINEAR, and SCIPexprcurvNegate().

Referenced by DECL_CURVCHECK(), SCIP_DECL_EXPRCURVATURE(), and SCIPexprcurvMonomial().

◆ SCIPexprcurvPower()

SCIP_EXPRCURV SCIPexprcurvPower ( SCIP_INTERVAL  basebounds,
SCIP_EXPRCURV  basecurv,
SCIP_Real  exponent 
)

gives curvature for base^exponent for given bounds and curvature of base-function and constant exponent

Parameters
baseboundsbounds on base function
basecurvcurvature of base function
exponentexponent

Definition at line 91 of file exprcurv.c.

References EPSISINT, SCIP_Interval::inf, SCIP_Bool, SCIP_EXPRCURV_CONCAVE, SCIP_EXPRCURV_CONVEX, SCIP_EXPRCURV_LINEAR, SCIP_EXPRCURV_UNKNOWN, SCIP_Real, SCIPexprcurvPower(), SCIPintervalSetBounds(), and SCIP_Interval::sup.

Referenced by SCIPexprcurvMonomial(), and SCIPexprcurvPower().

◆ SCIPexprcurvPowerInv()

SCIP_EXPRCURV SCIPexprcurvPowerInv ( SCIP_INTERVAL  basebounds,
SCIP_Real  exponent,
SCIP_EXPRCURV  powercurv 
)

gives required curvature for base so that base^exponent has given curvature under given bounds on base and constant exponent

returns curvature unknown if expected curvature cannot be obtained

Parameters
baseboundsbounds on base function
exponentexponent, must not be 0
powercurvexpected curvature for power

Definition at line 199 of file exprcurv.c.

References EPSISINT, SCIP_Interval::inf, SCIP_Bool, SCIP_EXPRCURV_CONCAVE, SCIP_EXPRCURV_CONVEX, SCIP_EXPRCURV_LINEAR, SCIP_EXPRCURV_UNKNOWN, SCIP_Real, SCIPexprcurvPowerInv(), SCIPintervalSetBounds(), and SCIP_Interval::sup.

Referenced by SCIP_DECL_EXPRCURVATURE(), SCIPexprcurvMonomialInv(), and SCIPexprcurvPowerInv().

◆ SCIPexprcurvMonomial()

SCIP_EXPRCURV SCIPexprcurvMonomial ( int  nfactors,
SCIP_Real exponents,
int *  factoridxs,
SCIP_EXPRCURV factorcurv,
SCIP_INTERVAL factorbounds 
)

gives curvature for a monomial with given curvatures and bounds for each factor

See Maranas and Floudas, Finding All Solutions of Nonlinearly Constrained Systems of Equations, JOGO 7, 1995 for the categorization in the case that all factors are linear.

Exponents can also be negative or rational.

Parameters
nfactorsnumber of factors in monomial
exponentsexponents in monomial, or NULL if all 1.0
factoridxsindices of factors (but not exponents), or NULL if identity mapping
factorcurvcurvature of each factor
factorboundsbounds of each factor

Definition at line 321 of file exprcurv.c.

References EPSGE, EPSISINT, EPSLE, FALSE, SCIP_Interval::inf, NULL, SCIP_Bool, SCIP_EXPRCURV_CONCAVE, SCIP_EXPRCURV_CONVEX, SCIP_EXPRCURV_LINEAR, SCIP_EXPRCURV_UNKNOWN, SCIP_Real, SCIPexprcurvMultiply(), SCIPexprcurvNegate(), SCIPexprcurvPower(), SCIP_Interval::sup, and TRUE.

◆ SCIPexprcurvMonomialInv()

SCIP_Bool SCIPexprcurvMonomialInv ( SCIP_EXPRCURV  monomialcurv,
int  nfactors,
SCIP_Real exponents,
SCIP_INTERVAL factorbounds,
SCIP_EXPRCURV factorcurv 
)

for a monomial with given bounds for each factor, gives condition on the curvature of each factor, so that monomial has a requested curvature, if possible

Returns
whether monomialcurv can be achieved
Parameters
monomialcurvdesired curvature
nfactorsnumber of factors in monomial
exponentsexponents in monomial, or NULL if all 1.0
factorboundsbounds of each factor
factorcurvbuffer to store required curvature of each factor

Definition at line 447 of file exprcurv.c.

References EPSGE, EPSISINT, EPSLE, FALSE, SCIP_Interval::inf, NULL, SCIP_EXPRCURV_CONCAVE, SCIP_EXPRCURV_CONVEX, SCIP_EXPRCURV_LINEAR, SCIP_EXPRCURV_UNKNOWN, SCIP_Real, SCIPexprcurvNegate(), SCIPexprcurvPowerInv(), SCIP_Interval::sup, and TRUE.

Referenced by DECL_CURVCHECK().

◆ SCIPexprcurvGetName()

const char* SCIPexprcurvGetName ( SCIP_EXPRCURV  curv)

gives name as string for a curvature

Parameters
curvcurvature

Definition at line 576 of file exprcurv.c.

References curvnames, and SCIP_EXPRCURV_LINEAR.

Referenced by createNlhdlrExprData(), and DECL_CURVCHECK().

◆ SCIPcreateExpr()

SCIP_RETCODE SCIPcreateExpr ( SCIP scip,
SCIP_EXPR **  expr,
SCIP_EXPRHDLR exprhdlr,
SCIP_EXPRDATA exprdata,
int  nchildren,
SCIP_EXPR **  children,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

creates and captures an expression with given expression data and children

Parameters
scipSCIP data structure
exprpointer where to store expression
exprhdlrexpression handler
exprdataexpression data (expression assumes ownership)
nchildrennumber of children
childrenchildren (can be NULL if nchildren is 0)
ownercreatedatadata to pass to ownercreate

Definition at line 964 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprCreate(), and Scip::set.

Referenced by SCIPcreateExpr2(), SCIPcreateExprAbs(), SCIPcreateExprCos(), SCIPcreateExprEntropy(), SCIPcreateExprErf(), SCIPcreateExprExp(), SCIPcreateExprLog(), SCIPcreateExprPow(), SCIPcreateExprProduct(), SCIPcreateExprSignpower(), SCIPcreateExprSin(), SCIPcreateExprSum(), SCIPcreateExprValue(), SCIPcreateExprVar(), and SCIPcreateExprVaridx().

◆ SCIPcreateExpr2()

SCIP_RETCODE SCIPcreateExpr2 ( SCIP scip,
SCIP_EXPR **  expr,
SCIP_EXPRHDLR exprhdlr,
SCIP_EXPRDATA exprdata,
SCIP_EXPR child1,
SCIP_EXPR child2,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

creates and captures an expression with given expression data and up to two children

Parameters
scipSCIP data structure
exprpointer where to store expression
exprhdlrexpression handler
exprdataexpression data
child1first child (can be NULL)
child2second child (can be NULL)
ownercreatedatadata to pass to ownercreate

Definition at line 985 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, and SCIPcreateExpr().

◆ SCIPcreateExprQuadratic()

SCIP_RETCODE SCIPcreateExprQuadratic ( SCIP scip,
SCIP_EXPR **  expr,
int  nlinvars,
SCIP_VAR **  linvars,
SCIP_Real lincoefs,
int  nquadterms,
SCIP_VAR **  quadvars1,
SCIP_VAR **  quadvars2,
SCIP_Real quadcoefs,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

creates and captures an expression representing a quadratic function

Parameters
scipSCIP data structure
exprpointer where to store expression
nlinvarsnumber of linear terms
linvarsarray with variables in linear part
lincoefsarray with coefficients of variables in linear part
nquadtermsnumber of quadratic terms
quadvars1array with first variables in quadratic terms
quadvars2array with second variables in quadratic terms
quadcoefsarray with coefficients of quadratic terms
ownercreatedatadata to pass to ownercreate

Definition at line 1023 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPallocBufferArray, SCIPcreateExprPow(), SCIPcreateExprProduct(), SCIPcreateExprSum(), SCIPcreateExprVar(), SCIPfreeBufferArray, and SCIPreleaseExpr().

Referenced by createConstraint(), readExpression(), and SCIPcreateConsQuadraticNonlinear().

◆ SCIPcreateExprMonomial()

SCIP_RETCODE SCIPcreateExprMonomial ( SCIP scip,
SCIP_EXPR **  expr,
int  nfactors,
SCIP_VAR **  vars,
SCIP_Real exponents,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

creates and captures an expression representing a monomial

Note
In deviation from the actual definition of monomials, we also allow for negative and rational exponents. So this function actually creates an expression for a signomial that has exactly one term.
Parameters
scipSCIP data structure
exprpointer where to store expression
nfactorsnumber of factors in monomial
varsvariables in the monomial
exponentsexponent in each factor, or NULL if all 1.0
ownercreatedatadata to pass to ownercreate

Definition at line 1131 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPallocBufferArray, SCIPcreateExprPow(), SCIPcreateExprProduct(), SCIPcreateExprValue(), SCIPcreateExprVar(), SCIPfreeBufferArray, and SCIPreleaseExpr().

Referenced by readPolynomial().

◆ SCIPappendExprChild()

SCIP_RETCODE SCIPappendExprChild ( SCIP scip,
SCIP_EXPR expr,
SCIP_EXPR child 
)

appends child to the children list of expr

Attention
Only use if you really know what you are doing. The expression handler of the expression needs to be able to handle an increase in the number of children.
Parameters
scipSCIP data structure
exprexpression
childexpression to be appended

Definition at line 1220 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprAppendChild(), and Scip::set.

Referenced by DECL_CURVCHECK(), nlhdlrExprGrowChildren(), parseTerm(), SCIP_DECL_EXPRSIMPLIFY(), SCIPappendExprSumExpr(), and simplifyTerm().

◆ SCIPreplaceExprChild()

SCIP_RETCODE SCIPreplaceExprChild ( SCIP scip,
SCIP_EXPR expr,
int  childidx,
SCIP_EXPR newchild 
)

overwrites/replaces a child of an expressions

The old child is released and the newchild is captured, unless they are the same (=same pointer).

Parameters
scipSCIP data structure
exprexpression which is going to replace a child
childidxindex of child being replaced
newchildthe new child

Definition at line 1238 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprReplaceChild(), Scip::set, and Scip::stat.

Referenced by collectLeafs(), replaceBinaryProducts(), SCIP_DECL_CONSACTIVE(), SCIPreplaceCommonSubexpressions(), and simplifyTerm().

◆ SCIPremoveExprChildren()

SCIP_RETCODE SCIPremoveExprChildren ( SCIP scip,
SCIP_EXPR expr 
)

remove all children of expr

Attention
Only use if you really know what you are doing. The expression handler of the expression needs to be able to handle the removal of all children.
Parameters
scipSCIP data structure
exprexpression

Definition at line 1257 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprRemoveChildren(), Scip::set, and Scip::stat.

Referenced by constructExpr().

◆ SCIPduplicateExpr()

SCIP_RETCODE SCIPduplicateExpr ( SCIP scip,
SCIP_EXPR expr,
SCIP_EXPR **  copyexpr,
SCIP_DECL_EXPR_MAPEXPR((*mapexpr))  ,
void *  mapexprdata,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

duplicates the given expression and its children

Parameters
scipSCIP data structure
exproriginal expression
copyexprbuffer to store duplicate of expr
mapexprdatadata of expression mapping function
ownercreatedatadata to pass to ownercreate

Definition at line 1271 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprCopy(), Scip::set, and Scip::stat.

Referenced by createCons(), SCIP_DECL_CONSTRANS(), SCIP_DECL_EXPRSIMPLIFY(), SCIPaddExprNonlinear(), SCIPaddNlpiProblemNlRows(), SCIPchgExprNonlinear(), and SCIPcreateNlpiProblemFromNlRows().

◆ SCIPduplicateExprShallow()

SCIP_RETCODE SCIPduplicateExprShallow ( SCIP scip,
SCIP_EXPR expr,
SCIP_EXPR **  copyexpr,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

duplicates the given expression, but reuses its children

Parameters
scipSCIP data structure
exproriginal expression
copyexprbuffer to store (shallow) duplicate of expr
ownercreatedatadata to pass to ownercreate

Definition at line 1291 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprDuplicateShallow(), and Scip::set.

Referenced by nlhdlrExprCreate().

◆ SCIPcopyExpr()

SCIP_RETCODE SCIPcopyExpr ( SCIP sourcescip,
SCIP targetscip,
SCIP_EXPR expr,
SCIP_EXPR **  copyexpr,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata,
SCIP_HASHMAP varmap,
SCIP_HASHMAP consmap,
SCIP_Bool  global,
SCIP_Bool valid 
)

copies an expression including children to use in a (possibly different) SCIP instance

Parameters
sourcescipsource SCIP data structure
targetsciptarget SCIP data structure
exproriginal expression
copyexprbuffer to store duplicate of expr
ownercreatedatadata to pass to ownercreate
varmapa SCIP_HASHMAP mapping variables of the source SCIP to the corresponding variables of the target SCIP, or NULL
consmapa hashmap to store the mapping of source constraints to the corresponding target constraints, or NULL
globalcreate a global or a local copy?
validpointer to store whether all checked or enforced constraints were validly copied

Definition at line 1308 of file scip_expr.c.

References COPY_MAPEXPR_DATA::consmap, COPY_MAPEXPR_DATA::global, Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprCopy(), Scip::set, Scip::stat, TRUE, COPY_MAPEXPR_DATA::valid, and COPY_MAPEXPR_DATA::varmap.

Referenced by SCIP_DECL_CONSCOPY().

◆ SCIPparseExpr()

SCIP_RETCODE SCIPparseExpr ( SCIP scip,
SCIP_EXPR **  expr,
const char *  exprstr,
const char **  finalpos,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

creates an expression from a string

We specify the grammar that defines the syntax of an expression. Loosely speaking, a Base will be any "block", a Factor is a Base to a power, a Term is a product of Factors and an Expression is a sum of Terms.

The actual definition:

Expression -> ["+" | "-"] Term { ("+" | "-" | "number *") ] Term }
Term       -> Factor { ("*" | "/" ) Factor }
Factor     -> Base [ "^" "number" | "^(" "number" ")" ]
Base       -> "number" | "<varname>" | "(" Expression ")" | Op "(" OpExpression ")

where [a|b] means a or b or none, (a|b) means a or b, {a} means 0 or more a.

Note that Op and OpExpression are undefined. Op corresponds to the name of an expression handler and OpExpression to whatever string the expression handler accepts (through its parse method).

Parameters
scipSCIP data structure
exprpointer to store the expr parsed
exprstrstring with the expr to parse
finalposbuffer to store the position of exprstr where we finished reading, or NULL if not of interest
ownercreatedatadata to pass to ownercreate

Definition at line 1370 of file scip_expr.c.

References NULL, parseExpr(), SCIP_CALL, SCIPblkmem(), SCIPgetNVars(), SCIPhashmapCreate(), and SCIPhashmapFree().

Referenced by SCIP_DECL_CONSPARSE(), and SCIP_DECL_EXPRPARSE().

◆ SCIPcaptureExpr()

void SCIPcaptureExpr ( SCIP_EXPR expr)

◆ SCIPreleaseExpr()

SCIP_RETCODE SCIPreleaseExpr ( SCIP scip,
SCIP_EXPR **  expr 
)

releases an expression (decrements usage count and possibly frees expression)

Parameters
scipSCIP data structure
exprpointer to expression to be released

Definition at line 1407 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprRelease(), Scip::set, and Scip::stat.

Referenced by addNlrow(), addRegularScholtes(), AMPLProblemHandler::LinearExprHandler::AddTerm(), buildSimplifiedProduct(), canonicalizeConstraints(), checkSymmetriesAreSymmetries(), AMPLProblemHandler::cleanup(), collectLeafs(), computeOffValues(), constructExpr(), createConstraint(), createNlRow(), createSOCExpression(), enforceSP10(), enforceSP11(), enforceSP12(), exprdataFree(), freeConstraint(), freeExprNode(), freeVarExprs(), getBinaryProductExpr(), getFactorizedBinaryQuadraticExpr(), mergeProductExprlist(), nlhdlrExprGrowChildren(), AMPLProblemHandler::OnBinary(), AMPLProblemHandler::OnHeader(), AMPLProblemHandler::OnUnary(), parseBase(), parseExpr(), parseFactor(), parseTerm(), presolveBinaryProducts(), readConstraints(), readExpression(), readObjective(), readPolynomial(), replaceBinaryProducts(), scaleConsSides(), SCIP_DECL_CONSACTIVE(), SCIP_DECL_CONSCOPY(), SCIP_DECL_CONSDELETE(), SCIP_DECL_CONSINITSOL(), SCIP_DECL_CONSPARSE(), SCIP_DECL_CONSTRANS(), SCIP_DECL_EXPRPARSE(), SCIP_DECL_EXPRSIMPLIFY(), SCIP_DECL_NLHDLRDETECT(), SCIP_DECL_NLHDLRFREEEXPRDATA(), SCIP_DECL_READERREAD(), SCIPaddBilinTermQuadratic(), SCIPaddExprNonlinear(), SCIPaddLinearVarNonlinear(), SCIPaddNlpiProblemNlRows(), SCIPaddQuadVarQuadratic(), SCIPaddSquareCoefQuadratic(), SCIPchgExprNonlinear(), SCIPcreateConsBasicSignpowerNonlinear(), SCIPcreateConsBasicSOC(), SCIPcreateConsBasicSOCNonlinear(), SCIPcreateConsQuadraticNonlinear(), SCIPcreateConsSOC(), SCIPcreateExprMonomial(), SCIPcreateExprQuadratic(), SCIPcreateNlpiProblemFromNlRows(), SCIPhasExprCurvature(), SCIPnlpiOracleChgExpr(), SCIPnlpiOracleDelVarSet(), SCIPreplaceCommonSubexpressions(), setQuadraticObj(), setupProblem(), and simplifyTerm().

◆ SCIPisExprVar()

SCIP_Bool SCIPisExprVar ( SCIP scip,
SCIP_EXPR expr 
)

returns whether an expression is a variable expression

Parameters
scipSCIP data structure
exprexpression

Definition at line 1421 of file scip_expr.c.

References NULL, SCIPexprIsVar(), and Scip::set.

Referenced by analyzeViolation(), buildQuadExprMatrix(), catchVarEvent(), catchVarEvents(), checkAndCollectQuadratic(), collectLeafs(), computeGradient(), computeOffValues(), computeSymmetryGroup(), constructExpr(), createAuxVar(), createNlRow(), detectSocNorm(), detectSocQuadraticSimple(), doSeachEcAggr(), dropVarEvent(), exprIsSemicontinuous(), fillGraphByNonlinearConss(), findUnlockedLinearVar(), forbidNonlinearVariablesMultiaggration(), forwardPropExpr(), generateCut(), isBinaryProduct(), isCandidate(), isPackingCons(), isSingleLockedCand(), nlrowaggrCreate(), presolveAddKKTQuadBilinearTerms(), presolveAddKKTQuadLinearTerms(), presolveAddKKTQuadQuadraticTerms(), presolveImplint(), presolveRedundantConss(), presolveSingleLockedVars(), printRow(), processNlRow(), propagateLocks(), readConstraints(), readObjective(), removeSingleLockedVars(), SCIP_DECL_CONSACTIVE(), SCIP_DECL_EVENTEXEC(), SCIP_DECL_EXPR_MAPEXPR(), SCIP_DECL_EXPR_OWNERCREATE(), SCIP_DECL_EXPR_OWNERFREE(), SCIP_DECL_EXPRSIMPLIFY(), SCIP_DECL_NLHDLRDETECT(), SCIPaddExprsViolScoreNonlinear(), SCIPaddExprViolScoreNonlinear(), SCIPaddNlRowGradientBenderscutOpt(), SCIPexprintCompile(), SCIPgetExprPartialDiffGradientDirNonlinear(), SCIPgetExprPartialDiffNonlinear(), SCIPisSOCNonlinear(), SCIPmarkExprPropagateNonlinear(), SCIPregisterExprUsageNonlinear(), and SCIPwriteMps().

◆ SCIPisExprValue()

◆ SCIPisExprSum()

◆ SCIPisExprProduct()

◆ SCIPisExprPower()

◆ SCIPprintExpr()

◆ SCIPprintExprDotInit()

SCIP_RETCODE SCIPprintExprDotInit ( SCIP scip,
SCIP_EXPRPRINTDATA **  printdata,
FILE *  file,
SCIP_EXPRPRINT_WHAT  whattoprint 
)

initializes printing of expressions in dot format to a give FILE* pointer

Parameters
scipSCIP data structure
printdatabuffer to store dot printing data
filefile to print to, or NULL for stdout
whattoprintinfo on what to print for each expression

Definition at line 1491 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprPrintDotInit(), Scip::set, and Scip::stat.

Referenced by SCIPshowExpr().

◆ SCIPprintExprDotInit2()

SCIP_RETCODE SCIPprintExprDotInit2 ( SCIP scip,
SCIP_EXPRPRINTDATA **  printdata,
const char *  filename,
SCIP_EXPRPRINT_WHAT  whattoprint 
)

initializes printing of expressions in dot format to a file with given filename

Parameters
scipSCIP data structure
printdatabuffer to store dot printing data
filenamename of file to print to
whattoprintinfo on what to print for each expression

Definition at line 1507 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprPrintDotInit2(), Scip::set, and Scip::stat.

◆ SCIPprintExprDot()

SCIP_RETCODE SCIPprintExprDot ( SCIP scip,
SCIP_EXPRPRINTDATA printdata,
SCIP_EXPR expr 
)

main part of printing an expression in dot format

Parameters
scipSCIP data structure
printdatadata as initialized by SCIPprintExprDotInit()
exprexpression to be printed

Definition at line 1523 of file scip_expr.c.

References Scip::messagehdlr, NULL, SCIP_CALL, SCIP_OKAY, SCIPexprPrintDot(), and Scip::set.

Referenced by SCIPshowExpr().

◆ SCIPprintExprDotFinal()

SCIP_RETCODE SCIPprintExprDotFinal ( SCIP scip,
SCIP_EXPRPRINTDATA **  printdata 
)

finishes printing of expressions in dot format

Parameters
scipSCIP data structure
printdatabuffer where dot printing data has been stored

Definition at line 1537 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprPrintDotFinal(), Scip::set, and Scip::stat.

Referenced by SCIPshowExpr().

◆ SCIPshowExpr()

SCIP_RETCODE SCIPshowExpr ( SCIP scip,
SCIP_EXPR expr 
)

shows a single expression by use of dot and gv

This function is meant for debugging purposes. It's signature is kept as simple as possible to make it easily callable from gdb, for example.

It prints the expression into a temporary file in dot format, then calls dot to create a postscript file, then calls ghostview (gv) to show the file. SCIP will hold until ghostscript is closed.

Parameters
scipSCIP data structure
exprexpression to be printed

Definition at line 1559 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_ERROR, SCIP_EXPRPRINT_ALL, SCIP_FILECREATEERROR, SCIP_OKAY, SCIPerrorMessage, SCIPprintExprDot(), SCIPprintExprDotFinal(), and SCIPprintExprDotInit().

◆ SCIPdismantleExpr()

SCIP_RETCODE SCIPdismantleExpr ( SCIP scip,
FILE *  file,
SCIP_EXPR expr 
)

prints structure of an expression a la Maple's dismantle

Parameters
scipSCIP data structure
filefile to print to, or NULL for stdout
exprexpression to dismantle

Definition at line 1596 of file scip_expr.c.

References Scip::mem, Scip::messagehdlr, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprDismantle(), Scip::set, and Scip::stat.

Referenced by detectSocQuadraticComplex(), and SCIP_DECL_EXPRESTIMATE().

◆ SCIPevalExpr()

SCIP_RETCODE SCIPevalExpr ( SCIP scip,
SCIP_EXPR expr,
SCIP_SOL sol,
SCIP_Longint  soltag 
)

evaluate an expression in a point

Iterates over expressions to also evaluate children, if necessary. Value can be received via SCIPexprGetEvalValue(). If an evaluation error (division by zero, ...) occurs, this value will be set to SCIP_INVALID.

If a nonzero soltag is passed, then only (sub)expressions are reevaluated that have a different solution tag. If a soltag of 0 is passed, then subexpressions are always reevaluated. The tag is stored together with the value and can be received via SCIPexprGetEvalTag().

Parameters
scipSCIP data structure
exprexpression to be evaluated
solsolution to be evaluated
soltagtag that uniquely identifies the solution (with its values), or 0.

Definition at line 1623 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprEval(), Scip::set, and Scip::stat.

Referenced by addTightEstimatorCuts(), computeOffValues(), computeViolation(), enforceExpr(), estimateConvexSecant(), initSepa(), SCIP_DECL_NLHDLREVALAUX(), SCIP_DECL_VERTEXPOLYFUN(), SCIPexprintEval(), and SCIPgetExprAbsOrigViolationNonlinear().

◆ SCIPgetExprNewSoltag()

SCIP_Longint SCIPgetExprNewSoltag ( SCIP scip)

returns a previously unused solution tag for expression evaluation

Parameters
scipSCIP data structure

Definition at line 1640 of file scip_expr.c.

References SCIP_Stat::exprlastsoltag, NULL, and Scip::stat.

Referenced by addTightEstimatorCuts(), consEnfo(), consSepa(), SCIP_DECL_CONSCHECK(), and SCIP_DECL_CONSENFOPS().

◆ SCIPevalExprGradient()

SCIP_RETCODE SCIPevalExprGradient ( SCIP scip,
SCIP_EXPR expr,
SCIP_SOL sol,
SCIP_Longint  soltag 
)

evaluates gradient of an expression for a given point

Initiates an expression walk to also evaluate children, if necessary. Value can be received via SCIPgetExprPartialDiffNonlinear(). If an error (division by zero, ...) occurs, this value will be set to SCIP_INVALID.

Parameters
scipSCIP data structure
exprexpression to be differentiated
solsolution to be evaluated (NULL for the current LP solution)
soltagtag that uniquely identifies the solution (with its values), or 0.

Definition at line 1656 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprEvalGradient(), Scip::set, and Scip::stat.

Referenced by computeGradient(), estimateGradient(), generateCut(), getConsRelViolation(), and SCIPaddNlRowGradientBenderscutOpt().

◆ SCIPevalExprHessianDir()

SCIP_RETCODE SCIPevalExprHessianDir ( SCIP scip,
SCIP_EXPR expr,
SCIP_SOL sol,
SCIP_Longint  soltag,
SCIP_SOL direction 
)

evaluates Hessian-vector product of an expression for a given point and direction

Evaluates children, if necessary. Value can be received via SCIPgetExprPartialDiffGradientDirNonlinear(). If an error (division by zero, ...) occurs, this value will be set to SCIP_INVALID.

Parameters
scipSCIP data structure
exprexpression to be differentiated
solsolution to be evaluated (NULL for the current LP solution)
soltagtag that uniquely identifies the solution (with its values), or 0.
directiondirection

Definition at line 1678 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprEvalHessianDir(), Scip::set, and Scip::stat.

◆ SCIPevalExprActivity()

SCIP_RETCODE SCIPevalExprActivity ( SCIP scip,
SCIP_EXPR expr 
)

possibly reevaluates and then returns the activity of the expression

Reevaluate activity if currently stored is no longer uptodate (some bound was changed since last evaluation).

The owner of the expression may overwrite the methods used to evaluate the activity, including whether the local or global domain of variables is used. By default (no owner, or owner doesn't overwrite activity evaluation), the local domain of variables is used.

Note
If expression is set to be integral, then activities are tightened to integral values. Thus, ensure that the integrality information is valid (if set to TRUE; the default (FALSE) is always ok).
Parameters
scipSCIP data structure
exprexpression

Definition at line 1706 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprEvalActivity(), Scip::set, and Scip::stat.

Referenced by checkSubproblemConvexity(), DECL_CURVCHECK(), deinitSolve(), detectSocQuadraticComplex(), detectSocQuadraticSimple(), estimateBivariateQuotient(), estimateUnivariateQuotient(), initSepa(), SCIP_DECL_EXPRCURVATURE(), SCIP_DECL_EXPRMONOTONICITY(), SCIP_DECL_NLHDLRESTIMATE(), SCIP_DECL_NLHDLRINITSEPA(), SCIPregisterExprUsageNonlinear(), and tryFillNlhdlrExprDataQuad().

◆ SCIPcompareExpr()

int SCIPcompareExpr ( SCIP scip,
SCIP_EXPR expr1,
SCIP_EXPR expr2 
)

compare expressions

Returns
-1, 0 or 1 if expr1 <, =, > expr2, respectively
Note
The given expressions are assumed to be simplified.
Parameters
scipSCIP data structure
expr1first expression
expr2second expression

Definition at line 1723 of file scip_expr.c.

References NULL, SCIPexprCompare(), and Scip::set.

Referenced by checkSymmetriesAreSymmetries(), DECL_CURVCHECK(), enforceSP11(), mergeProductExprlist(), SCIP_DECL_EXPRCOMPARE(), SCIP_DECL_EXPRSIMPLIFY(), and SCIP_DECL_SORTINDCOMP().

◆ SCIPhashExpr()

SCIP_RETCODE SCIPhashExpr ( SCIP scip,
SCIP_EXPR expr,
unsigned int *  hashval 
)

compute the hash value of an expression

Parameters
scipSCIP data structure
exprexpression
hashvalpointer to store the hash value

Definition at line 1735 of file scip_expr.c.

References SCIP_Mem::buffer, FALSE, hashExpr(), Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_LEAVEEXPR, SCIP_OKAY, SCIPexpriterCreate(), SCIPexpriterFree(), SCIPexpriterGetExprUserData(), SCIPexpriterInit(), SCIPexpriterSetStagesDFS(), Scip::set, Scip::stat, and SCIP_EXPRITER_USERDATA::uintval.

◆ SCIPsimplifyExpr()

SCIP_RETCODE SCIPsimplifyExpr ( SCIP scip,
SCIP_EXPR rootexpr,
SCIP_EXPR **  simplified,
SCIP_Bool changed,
SCIP_Bool infeasible,
SCIP_DECL_EXPR_OWNERCREATE((*ownercreate))  ,
void *  ownercreatedata 
)

simplifies an expression

This is largely inspired by Joel Cohen's Computer algebra and symbolic computation: Mathematical methods, in particular Chapter 3. The other fountain of inspiration are the simplifying methods of expr.c in SCIP 7.

Note: The things to keep in mind when adding simplification rules are the following. I will be using the product expressions (see expr_product.c) as an example. There are mainly 3 parts of the simplification process. You need to decide at which stage the simplification rule makes sense.

  1. Simplify each factor (simplifyFactor()): At this stage we got the children of the product expression. At this point, each child is simplified when viewed as a stand-alone expression, but not necessarily when viewed as child of a product expression. Rules like SP2, SP7, etc are enforced at this point.
  2. Multiply the factors (mergeProductExprlist()): At this point rules like SP4, SP5 and SP14 are enforced.
  3. Build the actual simplified product expression (buildSimplifiedProduct()): At this point rules like SP10, SP11, etc are enforced.

During steps 1 and 2 do not forget to set the flag changed to TRUE when something actually changes.

Definition of simplified expressions

An expression is simplified if it

  • is a value expression
  • is a var expression
  • is a product expression such that
    • SP1: every child is simplified
    • SP2: no child is a product
    • SP4: no two children are the same expression (those should be multiplied)
    • SP5: the children are sorted [commutative rule]
    • SP7: no child is a value
    • SP8: its coefficient is 1.0 (otherwise should be written as sum)
    • SP10: it has at least two children
    • TODO?: at most one child is an abs
    • SP11: no two children are expr*log(expr) (TODO: we could handle more complicated stuff like \(xy\log(x) \to - y * \mathrm{entropy}(x)\), but I am not sure this should happen at the simplification level; similar for \((xy) \log(xy)\), which currently simplifies to \(xy \log(xy)\))
    • SP12: if it has two children, then neither of them is a sum (expand sums)
    • SP13: no child is a sum with a single term
    • SP14: at most one child is an exp
  • is a power expression such that
    • POW1: exponent is not 0
    • POW2: exponent is not 1
    • POW3: its child is not a value
    • POW4: its child is simplified
    • POW5: if exponent is integer, its child is not a product
    • POW6: if exponent is integer, its child is not a sum with a single term ( \((2x)^2 \to 4x^2\))
    • POW7: if exponent is 2, its child is not a sum (expand sums)
    • POW8: its child is not a power unless \((x^n)^m\) with \(nm\) being integer and \(n\) or \(m\) fractional and \(n\) not being even integer
    • POW9: its child is not a sum with a single term with a positive coefficient: \((25x)^{0.5} \to 5 x^{0.5}\)
    • POW10: its child is not a binary variable: \(b^e, e > 0 \to b\); \(b^e, e < 0 \to b := 1\)
    • POW11: its child is not an exponential: \(\exp(\text{expr})^e \to \exp(e\cdot\text{expr})\)
  • is a signedpower expression such that

    • SPOW1: exponent is not 0
    • SPOW2: exponent is not 1
    • SPOW3: its child is not a value
    • SPOW4: its child is simplified
    • SPOW5: (TODO) do we want to distribute signpowers over products like we do for powers?
    • SPOW6: exponent is not an odd integer: (signpow odd expr) -> (pow odd expr)
    • SPOW8: if exponent is integer, its child is not a power
    • SPOW9: its child is not a sum with a single term: \(\mathrm{signpow}(25x,0.5) \to 5\mathrm{signpow}(x,0.5)\)
    • SPOW10: its child is not a binary variable: \(\mathrm{signpow}(b,e), e > 0 \to b\); \(\mathrm{signpow}(b,e), e < 0 \to b := 1\)
    • SPOW11: its child is not an exponential: \(\mathrm{signpow}(\exp(\text{expr}),e) \to \exp(e\cdot\text{expr})\)
    • TODO: what happens when child is another signed power?
    • TODO: if child ≥ 0 -> transform to normal power; if child < 0 -> transform to - normal power

    TODO: Some of these criteria are too restrictive for signed powers; for example, the exponent does not need to be an integer for signedpower to distribute over a product (SPOW5, SPOW6, SPOW8). Others can also be improved.

  • is a sum expression such that
    • SS1: every child is simplified
    • SS2: no child is a sum
    • SS3: no child is a value (values should go in the constant of the sum)
    • SS4: no two children are the same expression (those should be summed up)
    • SS5: the children are sorted [commutative rule]
    • SS6: it has at least one child
    • SS7: if it consists of a single child, then either constant is != 0.0 or coef != 1
    • SS8: no child has coefficient 0
    • SS9: if a child c is a product that has an exponential expression as one of its factors, then the coefficient of c is +/-1.0
    • SS10: if a child c is an exponential, then the coefficient of c is +/-1.0
  • it is a function with simplified arguments, but not all of them can be values
  • TODO? a logarithm doesn't have a product as a child
  • TODO? the exponent of an exponential is always 1
Ordering Rules (see SCIPexprCompare())
These rules define a total order on simplified expressions. There are two groups of rules, when comparing equal type expressions and different type expressions.

Equal type expressions:

  • OR1: u,v value expressions: u < v ⇔ val(u) < val(v)
  • OR2: u,v var expressions: u < v ⇔ SCIPvarGetIndex(var(u)) < SCIPvarGetIndex(var(v))
  • OR3: u,v are both sum or product expression: < is a lexicographical order on the terms
  • OR4: u,v are both pow: u < v ⇔ base(u) < base(v) or, base(u) = base(v) and expo(u) < expo(v)
  • OR5: u,v are \(u = f(u_1, ..., u_n), v = f(v_1, ..., v_m)\): u < v ⇔ For the first k such that \(u_k \neq v_k\), \(u_k < v_k\), or if such a \(k\) doesn't exist, then \(n < m\).

Different type expressions:

  • OR6: u value, v other: u < v always
  • OR7: u sum, v var or func: u < v ⇔ u < 0+v; In other words, if \(u = \sum_{i=1}^n \alpha_i u_i\), then u < v ⇔ \(u_n\) < v or if \(u_n\) = v and \(\alpha_n\) < 1.
  • OR8: u product, v pow, sum, var or func: u < v ⇔ u < 1*v; In other words, if \(u = \prod_{i=1}^n u_i\), then u < v ⇔ \(u_n\) < v. Note: since this applies only to simplified expressions, the form of the product is correct. Simplified products do not have constant coefficients.
  • OR9: u pow, v sum, var or func: u < v ⇔ u < v^1
  • OR10: u var, v func: u < v always
  • OR11: u func, v other type of func: u < v ⇔ name(type(u)) < name(type(v))
  • OR12: none of the rules apply: u < v ⇔ ! v < u

Examples:

  • x < x^2 ?: x is var and x^2 power, so none applies (OR12). Hence, we try to answer x^2 < x ?: x^2 < x ⇔ x < x or if x = x and 2 < 1 ⇔ 2 < 1 ⇔ False. So x < x^2 is True.
  • x < x^-1 –OR12→ ~(x^-1 < x) –OR9→ ~(x^-1 < x^1) –OR4→ ~(x < x or -1 < 1) → ~True → False
  • x*y < x –OR8→ x*y < 1*x –OR3→ y < x –OR2→ False
  • x*y < y –OR8→ x*y < 1*y –OR3→ y < x –OR2→ False
Algorithm

The recursive version of the algorithm is

EXPR simplify(expr)
   for c in 1..expr->nchildren
      expr->children[c] = simplify(expr->children[c])
   end
   return expr->exprhdlr->simplify(expr)
end

Important: Whatever is returned by a simplify callback has to be simplified. Also, all children of the given expression are already simplified.

Parameters
scipSCIP data structure
rootexprexpression to be simplified
simplifiedbuffer to store simplified expression
changedbuffer to store if rootexpr actually changed
infeasiblebuffer to store whether infeasibility has been detected
ownercreatedatadata to pass to ownercreate

Definition at line 1762 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprSimplify(), Scip::set, and Scip::stat.

Referenced by canonicalizeConstraints(), checkSymmetriesAreSymmetries(), and SCIP_DECL_CONSACTIVE().

◆ SCIPreplaceCommonSubexpressions()

SCIP_RETCODE SCIPreplaceCommonSubexpressions ( SCIP scip,
SCIP_EXPR **  exprs,
int  nexprs,
SCIP_Bool replacedroot 
)

replaces common sub-expressions in a given expression graph by using a hash key for each expression

The algorithm consists of two steps:

  1. traverse through all given expressions and compute for each of them a (not necessarily unique) hash
  2. initialize an empty hash table and traverse through all expression; check for each of them if we can find a structural equivalent expression in the hash table; if yes we replace the expression by the expression inside the hash table, otherwise we add it to the hash table
Note
the hash keys of the expressions are used for the hashing inside the hash table; to compute if two expressions (with the same hash) are structurally the same we use the function SCIPexprCompare().
Parameters
scipSCIP data structure
exprsexpressions (possibly replaced by equivalent on output)
nexprstotal number of expressions
replacedrootbuffer to store whether any root expression (expression in exprs) was replaced

Definition at line 1793 of file scip_expr.c.

References SCIP_Mem::buffer, FALSE, findEqualExpr(), hashExpr(), COMMONSUBEXPR_HASH_DATA::hashiterator, Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_LEAVEEXPR, SCIP_EXPRITER_VISITINGCHILD, SCIP_OKAY, SCIPcreateExpriter(), SCIPdebugMsg, SCIPexprCapture(), SCIPexprCompare(), SCIPexpriterFree(), SCIPexpriterGetChildExprDFS(), SCIPexpriterGetChildIdxDFS(), SCIPexpriterGetCurrent(), SCIPexpriterGetNext(), SCIPexpriterInit(), SCIPexpriterIsEnd(), SCIPexpriterSetStagesDFS(), SCIPexpriterSkipDFS(), SCIPmultihashCreate(), SCIPmultihashFree(), SCIPreleaseExpr(), SCIPreplaceExprChild(), Scip::set, COMMONSUBEXPR_HASH_DATA::set, and TRUE.

Referenced by canonicalizeConstraints().

◆ SCIPcomputeExprCurvature()

SCIP_RETCODE SCIPcomputeExprCurvature ( SCIP scip,
SCIP_EXPR expr 
)

computes the curvature of a given expression and all its subexpressions

Note
this function also evaluates all subexpressions w.r.t. current variable bounds
this function relies on information from the curvature callback of expression handlers only, consider using function SCIPhasExprCurvature() of the convex-nlhdlr instead, as that uses more information to deduce convexity
Parameters
scipSCIP data structure
exprexpression

Definition at line 1908 of file scip_expr.c.

References FALSE, Scip::mem, NULL, SCIP_Mem::probmem, SCIP_Bool, SCIP_CALL, SCIP_EXPRCURV_CONCAVE, SCIP_EXPRCURV_CONVEX, SCIP_EXPRCURV_LINEAR, SCIP_EXPRCURV_UNKNOWN, SCIP_EXPRITER_DFS, SCIP_EXPRITER_LEAVEEXPR, SCIP_OKAY, SCIPallocBufferArray, SCIPcalcMemGrowSize(), SCIPexprGetChildren(), SCIPexprGetCurvature(), SCIPexprGetHdlr(), SCIPexprGetNChildren(), SCIPexprhdlrCurvatureExpr(), SCIPexprhdlrHasCurvature(), SCIPexpriterCreate(), SCIPexpriterFree(), SCIPexpriterGetCurrent(), SCIPexpriterGetNext(), SCIPexpriterInit(), SCIPexpriterIsEnd(), SCIPexpriterSetStagesDFS(), SCIPexprSetCurvature(), SCIPfreeBufferArray, SCIPreallocBufferArray, Scip::set, and Scip::stat.

◆ SCIPcomputeExprIntegrality()

SCIP_RETCODE SCIPcomputeExprIntegrality ( SCIP scip,
SCIP_EXPR expr 
)

computes integrality information of a given expression and all its subexpressions

The integrality information can be accessed via SCIPexprIsIntegral().

Parameters
scipSCIP data structure
exprexpression

Definition at line 1988 of file scip_expr.c.

References FALSE, Scip::mem, NULL, SCIP_Mem::probmem, SCIP_Bool, SCIP_CALL, SCIP_EXPRITER_DFS, SCIP_EXPRITER_LEAVEEXPR, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprGetNChildren(), SCIPexprhdlrIntegralityExpr(), SCIPexpriterCreate(), SCIPexpriterFree(), SCIPexpriterGetCurrent(), SCIPexpriterGetNext(), SCIPexpriterInit(), SCIPexpriterIsEnd(), SCIPexpriterSetStagesDFS(), SCIPexprSetIntegrality(), Scip::set, and Scip::stat.

Referenced by collectLeafs(), and detectNlhdlrs().

◆ SCIPgetExprNVars()

SCIP_RETCODE SCIPgetExprNVars ( SCIP scip,
SCIP_EXPR expr,
int *  nvars 
)

returns the total number of variable expressions in an expression

The function counts variable expressions in common sub-expressions only once, but counts variables appearing in several variable expressions multiple times.

Parameters
scipSCIP data structure
exprexpression
nvarsbuffer to store the total number of variables

Definition at line 2031 of file scip_expr.c.

References FALSE, Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_EXPRITER_DFS, SCIP_OKAY, SCIPexprIsVar(), SCIPexpriterCreate(), SCIPexpriterFree(), SCIPexpriterGetNext(), SCIPexpriterInit(), SCIPexpriterIsEnd(), Scip::set, and Scip::stat.

Referenced by SCIP_DECL_NLHDLRDETECT().

◆ SCIPgetExprVarExprs()

SCIP_RETCODE SCIPgetExprVarExprs ( SCIP scip,
SCIP_EXPR expr,
SCIP_EXPR **  varexprs,
int *  nvarexprs 
)

returns all variable expressions contained in a given expression

The array to store all variable expressions needs to be at least of size the number of unique variable expressions in the expression which is given by SCIPgetExprNVars().

If every variable is represented by only one variable expression (common subexpression have been removed) then SCIPgetExprNVars() can be bounded by SCIPgetNTotalVars(). If, in addition, non-active variables have been removed from the expression, e.g., by simplifying, then SCIPgetExprNVars() can be bounded by SCIPgetNVars().

Note
function captures variable expressions
Parameters
scipSCIP data structure
exprexpression
varexprsarray to store all variable expressions
nvarexprsbuffer to store the total number of variable expressions

Definition at line 2069 of file scip_expr.c.

References FALSE, Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_EXPRITER_DFS, SCIP_OKAY, SCIPcaptureExpr(), SCIPexprIsVar(), SCIPexpriterCreate(), SCIPexpriterFree(), SCIPexpriterGetNext(), SCIPexpriterInit(), SCIPexpriterIsEnd(), Scip::set, and Scip::stat.

Referenced by computeOffValues(), SCIP_DECL_NLHDLRDETECT(), and storeVarExprs().

◆ SCIP_DECL_EXPRCURVATURE()

SCIP_DECL_EXPRCURVATURE ( SCIPcallExprCurvature  )

calls the curvature callback for an expression

See also
SCIP_DECL_EXPRCURVATURE

Returns unknown curvature if callback not implemented.

Definition at line 2115 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrCurvatureExpr(), and Scip::set.

◆ SCIP_DECL_EXPRMONOTONICITY()

SCIP_DECL_EXPRMONOTONICITY ( SCIPcallExprMonotonicity  )

calls the monotonicity callback for an expression

See also
SCIP_DECL_EXPRMONOTONICITY

Returns unknown monotonicity if callback not implemented.

Definition at line 2130 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrMonotonicityExpr(), and Scip::set.

◆ SCIPcallExprEval()

SCIP_RETCODE SCIPcallExprEval ( SCIP scip,
SCIP_EXPR expr,
SCIP_Real childrenvalues,
SCIP_Real val 
)

calls the eval callback for an expression with given values for children

Does not iterates over expressions, but requires values for children to be given. Value is not stored in expression, but returned in val. If an evaluation error (division by zero, ...) occurs, this value will be set to SCIP_INVALID.

Parameters
scipSCIP data structure
exprexpression to be evaluated
childrenvaluesvalues for children
valbuffer to store evaluated value

Definition at line 2146 of file scip_expr.c.

References SCIP_Mem::buffer, Scip::mem, NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrEvalExpr(), and Scip::set.

Referenced by atomic_userexpr::atomic_userexpr(), and evalExprInAux().

◆ SCIPcallExprEvalFwdiff()

SCIP_RETCODE SCIPcallExprEvalFwdiff ( SCIP scip,
SCIP_EXPR expr,
SCIP_Real childrenvalues,
SCIP_Real direction,
SCIP_Real val,
SCIP_Real dot 
)

calls the eval and fwdiff callback of an expression with given values for children

Does not iterates over expressions, but requires values for children and direction to be given.

Value is not stored in expression, but returned in val. If an evaluation error (division by zero, ...) occurs, this value will be set to SCIP_INVALID.

Direction is not stored in expression, but returned in dot. If an differentiation error (division by zero, ...) occurs, this value will be set to SCIP_INVALID.

Parameters
scipSCIP data structure
exprexpression to be evaluated
childrenvaluesvalues for children
directiondirection in which to differentiate
valbuffer to store evaluated value
dotbuffer to store derivative value

Definition at line 2173 of file scip_expr.c.

References SCIP_Mem::buffer, Scip::mem, NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrEvalFwDiffExpr(), and Scip::set.

Referenced by atomic_userexpr::atomic_userexpr().

◆ SCIP_DECL_EXPRINTEVAL()

SCIP_DECL_EXPRINTEVAL ( SCIPcallExprInteval  )

calls the interval evaluation callback for an expression

See also
SCIP_DECL_EXPRINTEVAL

Returns entire interval if callback not implemented.

Definition at line 2197 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrIntEvalExpr(), and Scip::set.

◆ SCIP_DECL_EXPRESTIMATE()

SCIP_DECL_EXPRESTIMATE ( SCIPcallExprEstimate  )

calls the estimate callback for an expression

See also
SCIP_DECL_EXPRESTIMATE

Returns without success if callback not implemented.

Definition at line 2213 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrEstimateExpr(), and Scip::set.

◆ SCIP_DECL_EXPRINITESTIMATES()

SCIP_DECL_EXPRINITESTIMATES ( SCIPcallExprInitestimates  )

calls the initial estimators callback for an expression

See also
SCIP_DECL_EXPRINITESTIMATES

Returns no estimators if callback not implemented.

Definition at line 2230 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrInitEstimatesExpr(), and Scip::set.

◆ SCIP_DECL_EXPRSIMPLIFY()

SCIP_DECL_EXPRSIMPLIFY ( SCIPcallExprSimplify  )

calls the simplify callback for an expression

See also
SCIP_DECL_EXPRSIMPLIFY

Returns unmodified expression if simplify callback not implemented.

Does not simplify descendants (children, etc). Use SCIPsimplifyExpr() for that.

Definition at line 2248 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrSimplifyExpr(), and Scip::set.

◆ SCIP_DECL_EXPRREVERSEPROP()

SCIP_DECL_EXPRREVERSEPROP ( SCIPcallExprReverseprop  )

calls the reverse propagation callback for an expression

See also
SCIP_DECL_EXPRREVERSEPROP

Returns unmodified childrenbounds if reverseprop callback not implemented.

calls the reverse propagation callback for an expression

See also
SCIP_DECL_EXPRREVERSEPROP

Returns unmodified childrenbounds if reverseprop callback not implemented.

Definition at line 2266 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIPexprGetHdlr(), SCIPexprhdlrReversePropExpr(), and Scip::set.

◆ SCIPcreateExpriter()

◆ SCIPfreeExpriter()

◆ SCIPcheckExprQuadratic()

SCIP_RETCODE SCIPcheckExprQuadratic ( SCIP scip,
SCIP_EXPR expr,
SCIP_Bool isquadratic 
)

checks whether an expression is quadratic

An expression is quadratic if it is either a square (of some expression), a product (of two expressions), or a sum of terms where at least one is a square or a product.

Use SCIPexprGetQuadraticData() to get data about the representation as quadratic.

Parameters
scipSCIP data structure
exprexpression
isquadraticbuffer to store result

Definition at line 2326 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprCheckQuadratic(), and Scip::set.

Referenced by DECL_CURVCHECK(), isCandidate(), processNlRow(), SCIP_DECL_NLHDLRDETECT(), and SCIPcheckQuadraticNonlinear().

◆ SCIPfreeExprQuadratic()

void SCIPfreeExprQuadratic ( SCIP scip,
SCIP_EXPR expr 
)

frees information on quadratic representation of an expression

Before doing changes to an expression, it can be useful to call this function.

Parameters
scipSCIP data structure
exprexpression

Definition at line 2344 of file scip_expr.c.

References Scip::mem, NULL, SCIP_Mem::probmem, and SCIPexprFreeQuadratic().

Referenced by deinitSolve().

◆ SCIPevalExprQuadratic()

SCIP_Real SCIPevalExprQuadratic ( SCIP scip,
SCIP_EXPR expr,
SCIP_SOL sol 
)

evaluates quadratic term in a solution

Note
This requires that every expressiion used in the quadratic data is a variable expression.

evaluates quadratic term in a solution

Note
This requires that every expression used in the quadratic data is a variable expression.
Parameters
scipSCIP data structure
exprquadratic expression
solsolution to evaluate, or NULL for LP solution

Definition at line 2359 of file scip_expr.c.

References NULL, SCIP_Real, SCIPexprGetQuadraticBilinTerm(), SCIPexprGetQuadraticData(), SCIPexprGetQuadraticQuadTerm(), SCIPexprIsVar(), SCIPgetSolVal(), SCIPgetVarExprVar(), and Scip::set.

◆ SCIPprintExprQuadratic()

SCIP_RETCODE SCIPprintExprQuadratic ( SCIP scip,
SCIP_EXPR expr 
)

prints quadratic expression

Parameters
scipSCIP data structure
exprquadratic expression

Definition at line 2419 of file scip_expr.c.

References NULL, SCIP_CALL, SCIP_OKAY, SCIP_Real, SCIPexprGetQuadraticBilinTerm(), SCIPexprGetQuadraticData(), SCIPexprGetQuadraticQuadTerm(), SCIPinfoMessage(), and SCIPprintExpr().

Referenced by SCIP_DECL_NLHDLRDETECT().

◆ SCIPcomputeExprQuadraticCurvature()

SCIP_RETCODE SCIPcomputeExprQuadraticCurvature ( SCIP scip,
SCIP_EXPR expr,
SCIP_EXPRCURV curv,
SCIP_HASHMAP assumevarfixed,
SCIP_Bool  storeeigeninfo 
)

checks the curvature of the quadratic expression

For this, it builds the matrix Q of quadratic coefficients and computes its eigenvalues using LAPACK. If Q is

  • semidefinite positive -> curv is set to convex,
  • semidefinite negative -> curv is set to concave,
  • otherwise -> curv is set to unknown.

If assumevarfixed is given and some expressions in quadratic terms correspond to variables present in this hashmap, then the corresponding rows and columns are ignored in the matrix Q.

Parameters
scipSCIP data structure
exprquadratic expression
curvpointer to store the curvature of quadratics
assumevarfixedhashmap containing variables that should be assumed to be fixed, or NULL
storeeigeninfowhether the eigenvalues and eigenvectors should be stored

Definition at line 2535 of file scip_expr.c.

References SCIP_Mem::buffer, Scip::mem, Scip::messagehdlr, NULL, SCIP_Mem::probmem, SCIP_CALL, SCIP_OKAY, SCIPexprComputeQuadraticCurvature(), and Scip::set.

Referenced by DECL_CURVCHECK(), and SCIP_DECL_NLHDLRDETECT().