Scippy

SCIP

Solving Constraint Integer Programs

Coding style guidelines

We follow the following coding style guidelines and recommend them for all developers.

Spacing:

  • Indentation is 3 spaces. No tabs anywhere in the code.
  • Every opening parenthesis requires an additional indentation of 3 spaces.

    SCIP_CALL( SCIPaddBoolParam(scip, "branching/relpscost/storesemiinitcosts",
    "should strong branching result be considered for pseudo costs if the other direction was infeasible?",
    &branchruledata->storesemiinitcosts, TRUE, DEFAULT_STORESEMIINITCOSTS,
    NULL, NULL) );

    (Source: src/scip/branch_relpscost.c)

  • Spaces around all operators.
  • Spaces around the arguments inside an if/for/while-statement, as well as inside macros (e.g., SCIP_CALL).
  • No spaces between control structure keywords like "if", "for", "while", "switch" and the corresponding brackets.
  • No spaces between a function name and the parenthesis in both the definition and function calls.
  • Braces are on a new line and not indented.
  • Braces in if/for-statements should only be omitted if they enclose a single line.

    for( v = 0; v < nandvars; v++ )
    {
    /* don't rely on the and conshdlr removing fixed variables
    * @todo fix the and conshdlr in that respect
    */
    {
    SCIP_CALL( binvarGetActiveProbindex(scip, andvars[v], &probindex) );
    if( probindex >= 0 )
    nlcount[probindex]++;
    }
    }

    (Source: src/scip/branch_relpscost.c)

  • In function declarations, every parameter is on a new line. The name of the parameter starts at column 26, the comment starts at column 46 (if column-count starts with 1).
  • Maximal line length is 120 characters.
  • Always only one declaration in a line.
  • Variable names should be all lower case.

    /** counts number of nonlinear constraints in which each variable appears */
    static
    SCIP* scip, /**< SCIP data structure */
    int* nlcount, /**< pointer to array for storing count values */
    int nlcountsize, /**< buffer for storing length of nlcount array */
    int* nlcountmax /**< buffer for storing maximum value in nlcount array */
    )
    {
    SCIP_CONSHDLR* andconshdlr;
    SCIP_VAR** vars;
    int nvars;
    int i;

    (Source: src/scip/branch_relpscost.c)

  • Blank lines are inserted where it improves readability.
  • Multiple blank lines are used to structure the code where single blank lines are insufficient, e.g., between differrent sections of the code.

    /** execution method of primal heuristic */
    static
    SCIP_DECL_HEUREXEC(heurExecXyz)
    { /*lint --e{715}*/
    SCIPerrorMessage("method of xyz primal heuristic not implemented yet\n");
    SCIPABORT(); /*lint --e{527}*/
    return SCIP_OKAY;
    }
    /*
    * primal heuristic specific interface methods
    */
    /** creates the xyz primal heuristic and includes it in SCIP */
    SCIP_RETCODE SCIPincludeHeurXyz(
    SCIP* scip /**< SCIP data structure */
    )
    {
    SCIP_HEURDATA* heurdata;
    SCIP_HEUR* heur;
    /* create xyz primal heuristic data */
    heurdata = NULL;
    heur = NULL;

    (Source: src/scip/heur_xyz.c)

Naming:

Documentation:

  • Document functions, parameters, and variables in a doxygen conformed way.
  • Please do not leave code in comments that has been commented out, don't use #if 0. Instead put the code within defines #ifdef SCIP_DISABLED_CODE and add an explanation.
  • Todos need double stars to be registered by doxygen.
  • When documenting methods, the first brief description starts with lower case and is separated by semi-colons, if necessary The longer description starts capitalized and consists of complete sentences. If the documentation consists of multiple lines, the comment end must be on a new line.

    /** copies directed graph structure
    *
    * The copying procedure uses the memory of the passed SCIP instance. The user must ensure that the digraph lives
    * as most as long as the SCIP instance.
    *
    * @note The data in nodedata is copied verbatim. This possibly has to be adapted by the user.
    */
    SCIP* scip, /**< SCIP data structure */
    SCIP_DIGRAPH** targetdigraph, /**< pointer to store the copied directed graph */
    SCIP_DIGRAPH* sourcedigraph /**< source directed graph */
    );

    (Source: src/scip/scip_datastructures.h)

Customize (x)emacs

If you are using (x)emacs, you can use the following customization for the c++-mode. These settings satisfy the coding guidelines of SCIP.

(add-hook 'c++-mode-hook
(function
(lambda ()
;; SCIP customizations for c-mode and c++-mode
(setq-default c-basic-offset 3)
(c-set-offset 'substatement-open 0)
(c-set-offset 'statement-case-open 0)
(c-set-offset 'brace-list-open '-)
(c-set-offset 'inextern-lang '0)
(c-set-offset 'arglist-intro '+)
(c-set-offset 'arglist-cont 0)
(c-set-offset 'arglist-cont-nonempty '+)
(c-set-offset 'arglist-close '+)
(set-variable 'fill-column 120)
;; this will make sure spaces are used instead of tabs
(setq tab-width 8 indent-tabs-mode nil)
)))

Customize eclipse

Eclipse user can use the profile below. This profile does not match the SCIP coding guideline completely.

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<profiles version="1">
<profile kind="CodeFormatterProfile" name="scip" version="1">
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<setting id="org.eclipse.cdt.core.formatter.insert_new_line_in_empty_block" value="insert"/>
<setting id="org.eclipse.cdt.core.formatter.lineSplit" value="124"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_before_comma_in_base_types" value="do not insert"/>
<setting id="org.eclipse.cdt.core.formatter.keep_else_statement_on_same_line" value="false"/>
<setting id="org.eclipse.cdt.core.formatter.indent_switchstatements_compare_to_switch" value="false"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_after_opening_brace_in_array_initializer" value="insert"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_before_comma_in_method_declaration_parameters" value="do not insert"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_after_opening_paren_in_if" value="insert"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_after_opening_paren_in_exception_specification" value="do not insert"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_after_comma_in_base_types" value="insert"/>
<setting id="org.eclipse.cdt.core.formatter.indent_body_declarations_compare_to_access_specifier" value="true"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_before_closing_paren_in_method_declaration" value="do not insert"/>
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<setting id="org.eclipse.cdt.core.formatter.alignment_for_expressions_in_array_initializer" value="16"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_after_comma_in_declarator_list" value="insert"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_before_opening_brace_in_method_declaration" value="insert"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_before_opening_paren_in_while" value="do not insert"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_after_opening_bracket" value="do not insert"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_after_opening_angle_bracket_in_template_parameters" value="do not insert"/>
<setting id="org.eclipse.cdt.core.formatter.continuation_indentation" value="1"/>
<setting id="org.eclipse.cdt.core.formatter.alignment_for_expression_list" value="0"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_after_opening_paren_in_method_declaration" value="do not insert"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_before_comma_in_template_parameters" value="do not insert"/>
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<setting id="org.eclipse.cdt.core.formatter.insert_space_after_binary_operator" value="insert"/>
<setting id="org.eclipse.cdt.core.formatter.alignment_for_conditional_expression" value="16"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_between_empty_parens_in_method_invocation" value="do not insert"/>
<setting id="org.eclipse.cdt.core.formatter.insert_space_before_comma_in_array_initializer" value="do not insert"/>
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</profiles>