Scippy

SCIP

Solving Constraint Integer Programs

reader_fix.c
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1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2 /* */
3 /* This file is part of the program and library */
4 /* SCIP --- Solving Constraint Integer Programs */
5 /* */
6 /* Copyright (c) 2002-2024 Zuse Institute Berlin (ZIB) */
7 /* */
8 /* Licensed under the Apache License, Version 2.0 (the "License"); */
9 /* you may not use this file except in compliance with the License. */
10 /* You may obtain a copy of the License at */
11 /* */
12 /* http://www.apache.org/licenses/LICENSE-2.0 */
13 /* */
14 /* Unless required by applicable law or agreed to in writing, software */
15 /* distributed under the License is distributed on an "AS IS" BASIS, */
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17 /* See the License for the specific language governing permissions and */
18 /* limitations under the License. */
19 /* */
20 /* You should have received a copy of the Apache-2.0 license */
21 /* along with SCIP; see the file LICENSE. If not visit scipopt.org. */
22 /* */
23 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
24 
25 /**@file reader_fix.c
26  * @ingroup DEFPLUGINS_READER
27  * @brief file reader for variable fixings
28  * @author Tobias Achterberg
29  *
30  * This reader allows to read a file containing fixation values for variables of the current problem. Each line of the
31  * file should have format
32  *
33  * <variable name> <value to fix>
34  *
35  * Note that only a subset of the variables may need to appear in the file. Lines with unknown variable names are
36  * ignored. The writing functionality is currently not supported.
37  *
38  * @note The format is equal to the (not xml) solution format of SCIP.
39  *
40  */
41 
42 /*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
43 
44 #include "scip/pub_fileio.h"
45 #include "scip/pub_message.h"
46 #include "scip/pub_misc.h"
47 #include "scip/pub_reader.h"
48 #include "scip/pub_var.h"
49 #include "scip/reader_fix.h"
50 #include "scip/scip_general.h"
51 #include "scip/scip_message.h"
52 #include "scip/scip_numerics.h"
53 #include "scip/scip_prob.h"
54 #include "scip/scip_reader.h"
55 #include "scip/scip_solve.h"
56 #include "scip/scip_var.h"
57 #include <string.h>
58 
59 #if !defined(_WIN32) && !defined(_WIN64)
60 #include <strings.h> /*lint --e{766}*/ /* needed for strncasecmp() */
61 #endif
62 
63 
64 
65 #define READER_NAME "fixreader"
66 #define READER_DESC "file reader for variable fixings"
67 #define READER_EXTENSION "fix"
68 
69 
70 /*
71  * local methods
72  */
73 
74 /** reads the given solution file */
75 static
77  SCIP* scip, /**< SCIP data structure */
78  const char* filename /**< name of the input file */
79  )
80 {
81  SCIP_RETCODE retcode;
82  SCIP_FILE* file;
83  SCIP_Bool error;
84  SCIP_Bool unknownvariablemessage;
85  int lineno;
86  int nfixed;
87 
88  assert(scip != NULL);
89  assert(filename != NULL);
90 
91  /* open input file */
92  file = SCIPfopen(filename, "r");
93  if( file == NULL )
94  {
95  SCIPerrorMessage("cannot open file <%s> for reading\n", filename);
96  SCIPprintSysError(filename);
97  return SCIP_NOFILE;
98  }
99 
100  /* read the file */
101  error = FALSE;
102  unknownvariablemessage = FALSE;
103  lineno = 0;
104  nfixed = 0;
105  while( !SCIPfeof(file) && !error )
106  {
107  char buffer[SCIP_MAXSTRLEN];
108  char varname[SCIP_MAXSTRLEN];
109  char valuestring[SCIP_MAXSTRLEN];
110  char objstring[SCIP_MAXSTRLEN];
111  char format[SCIP_MAXSTRLEN];
112  SCIP_VAR* var;
113  SCIP_Real value;
114  SCIP_Bool infeasible;
115  SCIP_Bool fixed;
116  int nread;
117 
118  /* get next line */
119  if( SCIPfgets(buffer, (int) sizeof(buffer), file) == NULL )
120  break;
121  lineno++;
122 
123  /* the lines "solution status: ..." and "objective value: ..." may preceed the solution information */
124  if( strncasecmp(buffer, "solution status:", 16) == 0 || strncasecmp(buffer, "objective value:", 16) == 0 )
125  continue;
126 
127  /* parse the line */
128  (void) SCIPsnprintf(format, SCIP_MAXSTRLEN, "%%%ds %%%ds %%%ds\n", SCIP_MAXSTRLEN, SCIP_MAXSTRLEN, SCIP_MAXSTRLEN);
129  nread = sscanf(buffer, format, varname, valuestring, objstring);
130  if( nread < 2 )
131  {
132  SCIPerrorMessage("invalid input line %d in solution file <%s>: <%s>\n", lineno, filename, buffer);
133  error = TRUE;
134  break;
135  }
136 
137  /* find the variable */
138  var = SCIPfindVar(scip, varname);
139  if( var == NULL )
140  {
141  if( !unknownvariablemessage )
142  {
143  SCIPwarningMessage(scip, "unknown variable <%s> in line %d of solution file <%s>\n", varname, lineno, filename);
144  SCIPwarningMessage(scip, " (further unknown variables are ignored)\n");
145  unknownvariablemessage = TRUE;
146  }
147  continue;
148  }
149 
150  /* cast the value */
151  if( strncasecmp(valuestring, "inv", 3) == 0 )
152  continue;
153  else if( strncasecmp(valuestring, "+inf", 4) == 0 || strncasecmp(valuestring, "inf", 3) == 0 )
154  value = SCIPinfinity(scip);
155  else if( strncasecmp(valuestring, "-inf", 4) == 0 )
156  value = -SCIPinfinity(scip);
157  else
158  {
159  /* coverity[secure_coding] */
160  nread = sscanf(valuestring, "%lf", &value);
161  if( nread != 1 )
162  {
163  SCIPerrorMessage("invalid solution value <%s> for variable <%s> in line %d of solution file <%s>\n",
164  valuestring, varname, lineno, filename);
165  error = TRUE;
166  break;
167  }
168  }
169 
170  /* fix the variable */
171  retcode = SCIPfixVar(scip, var, value, &infeasible, &fixed);
172  if( retcode != SCIP_OKAY )
173  {
174  SCIPerrorMessage("Error fixing variable <%s> to value %.15g in line %d of bounds file <%s>\n",
175  varname, value, lineno, filename);
176  error = TRUE;
177  break;
178  }
179  if( infeasible )
180  {
181  SCIPerrorMessage("infeasible solution value of <%s>[%.15g,%.15g] to %.15g in line %d of solution file <%s>\n",
182  varname, SCIPvarGetLbGlobal(var), SCIPvarGetUbGlobal(var), value, lineno, filename);
183  error = TRUE;
184  break;
185  }
186  if( fixed )
187  nfixed++;
188  }
189 
190  /* close input file */
191  SCIPfclose(file);
192 
193  /* display result */
194  SCIPverbMessage(scip, SCIP_VERBLEVEL_NORMAL, NULL, "fixed %d variables from solution file <%s>\n", nfixed, filename);
195 
196  if( error )
197  return SCIP_READERROR;
198  else
199  return SCIP_OKAY;
200 }
201 
202 /*
203  * Callback methods of reader
204  */
205 
206 /** copy method for reader plugins (called when SCIP copies plugins) */
207 static
208 SCIP_DECL_READERCOPY(readerCopyFix)
209 { /*lint --e{715}*/
210  assert(scip != NULL);
211  assert(reader != NULL);
212  assert(strcmp(SCIPreaderGetName(reader), READER_NAME) == 0);
213 
214  /* call inclusion method of reader */
216 
217  return SCIP_OKAY;
218 }
219 
220 /** problem reading method of reader */
221 static
222 SCIP_DECL_READERREAD(readerReadFix)
223 { /*lint --e{715}*/
224  assert(reader != NULL);
225  assert(strcmp(SCIPreaderGetName(reader), READER_NAME) == 0);
226  assert(result != NULL);
227 
228  *result = SCIP_DIDNOTRUN;
229 
231  {
232  SCIPerrorMessage("reading of fixing file is only possible after a problem was created\n");
233  return SCIP_READERROR;
234  }
235 
236  /* free transformed problem, s.t. fixings are applied to the original problem */
238 
239  /* read (partial) solution from fixing file */
240  SCIP_CALL( readSol(scip, filename) );
241 
242  *result = SCIP_SUCCESS;
243 
244  return SCIP_OKAY;
245 }
246 
247 /*
248  * fix file reader specific interface methods
249  */
250 
251 /** includes the fix file reader in SCIP */
253  SCIP* scip /**< SCIP data structure */
254  )
255 {
256  SCIP_READER* reader;
257 
258  /* include reader */
260 
261  /* set non fundamental callbacks via setter functions */
262  SCIP_CALL( SCIPsetReaderCopy(scip, reader, readerCopyFix) );
263  SCIP_CALL( SCIPsetReaderRead(scip, reader, readerReadFix) );
264 
265  return SCIP_OKAY;
266 }
#define READER_EXTENSION
Definition: reader_fix.c:67
#define NULL
Definition: def.h:267
SCIP_STAGE SCIPgetStage(SCIP *scip)
Definition: scip_general.c:380
SCIP_Real SCIPvarGetLbGlobal(SCIP_VAR *var)
Definition: var.c:18079
#define SCIP_MAXSTRLEN
Definition: def.h:288
public solving methods
const char * SCIPreaderGetName(SCIP_READER *reader)
Definition: reader.c:557
#define FALSE
Definition: def.h:94
SCIP_Real SCIPinfinity(SCIP *scip)
int SCIPsnprintf(char *t, int len, const char *s,...)
Definition: misc.c:10877
#define TRUE
Definition: def.h:93
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:63
public methods for problem variables
public methods for SCIP variables
void SCIPwarningMessage(SCIP *scip, const char *formatstr,...)
Definition: scip_message.c:120
static SCIP_DECL_READERREAD(readerReadFix)
Definition: reader_fix.c:222
public methods for numerical tolerances
SCIP_VAR * SCIPfindVar(SCIP *scip, const char *name)
Definition: scip_prob.c:2685
SCIP_FILE * SCIPfopen(const char *path, const char *mode)
Definition: fileio.c:153
SCIP_Real SCIPvarGetUbGlobal(SCIP_VAR *var)
Definition: var.c:18089
SCIP_RETCODE SCIPincludeReaderFix(SCIP *scip)
Definition: reader_fix.c:252
static SCIP_RETCODE readSol(SCIP *scip, const char *filename)
Definition: reader_fix.c:76
#define SCIPerrorMessage
Definition: pub_message.h:64
int SCIPfeof(SCIP_FILE *stream)
Definition: fileio.c:227
struct SCIP_File SCIP_FILE
Definition: pub_fileio.h:43
char * SCIPfgets(char *s, int size, SCIP_FILE *stream)
Definition: fileio.c:200
#define READER_NAME
Definition: reader_fix.c:65
#define SCIP_CALL(x)
Definition: def.h:380
void SCIPverbMessage(SCIP *scip, SCIP_VERBLEVEL msgverblevel, FILE *file, const char *formatstr,...)
Definition: scip_message.c:225
wrapper functions to map file i/o to standard or zlib file i/o
public data structures and miscellaneous methods
SCIP_RETCODE SCIPfreeTransform(SCIP *scip)
Definition: scip_solve.c:3334
#define SCIP_Bool
Definition: def.h:91
SCIP_RETCODE SCIPincludeReaderBasic(SCIP *scip, SCIP_READER **readerptr, const char *name, const char *desc, const char *extension, SCIP_READERDATA *readerdata)
Definition: scip_reader.c:109
void SCIPprintSysError(const char *message)
Definition: misc.c:10769
file reader for variable fixings
SCIP_RETCODE SCIPfixVar(SCIP *scip, SCIP_VAR *var, SCIP_Real fixedval, SCIP_Bool *infeasible, SCIP_Bool *fixed)
Definition: scip_var.c:8278
SCIP_RETCODE SCIPsetReaderCopy(SCIP *scip, SCIP_READER *reader, SCIP_DECL_READERCOPY((*readercopy)))
Definition: scip_reader.c:147
general public methods
public methods for message output
#define SCIP_Real
Definition: def.h:173
public methods for input file readers
public methods for message handling
SCIP_RETCODE SCIPsetReaderRead(SCIP *scip, SCIP_READER *reader, SCIP_DECL_READERREAD((*readerread)))
Definition: scip_reader.c:195
int SCIPfclose(SCIP_FILE *fp)
Definition: fileio.c:232
static SCIP_DECL_READERCOPY(readerCopyFix)
Definition: reader_fix.c:208
public methods for reader plugins
public methods for global and local (sub)problems
#define READER_DESC
Definition: reader_fix.c:66