1 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ 2 /* */ 3 /* This file is part of the program and library */ 4 /* SCIP --- Solving Constraint Integer Programs */ 5 /* */ 6 /* Copyright (c) 2002-2023 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, */ 16 /* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */ 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 76 SCIP_RETCODE readSol( 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 */ 215 SCIP_CALL( SCIPincludeReaderFix(scip) ); 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; 229 230 if( SCIPgetStage(scip) < SCIP_STAGE_PROBLEM ) 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 */ 237 SCIP_CALL( SCIPfreeTransform(scip) ); 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 */ 252 SCIP_RETCODE SCIPincludeReaderFix( 253 SCIP* scip /**< SCIP data structure */ 254 ) 255 { 256 SCIP_READER* reader; 257 258 /* include reader */ 259 SCIP_CALL( SCIPincludeReaderBasic(scip, &reader, READER_NAME, READER_DESC, READER_EXTENSION, NULL) ); 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 } 267