Scippy

SCIP

Solving Constraint Integer Programs

spring.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, */
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 spring.c
26 * @brief Coil Compression Spring Design model
27 * @author Stefan Vigerske
28 *
29 * This example shows how to setup quadratic and nonlinear constraints in SCIP when using SCIP as callable library.
30 * The example implements a model for the design of a coil compression spring as it can be found in the GAMS model library:
31 * https://www.gams.com/latest/gamslib_ml/libhtml/gamslib_spring.html
32 *
33 * The task is to find a minimum volume of a wire for the production of a coil compression spring.
34 *
35 * Original model source:
36 * @par
37 * E. Sangren@n
38 * Nonlinear Integer and Discrete Programming in Mechanical Design Optimization@n
39 * Journal of Mechanical Design, Trans. ASME 112 (1990), 223-229
40 */
41
42/*--+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
43
44#define _USE_MATH_DEFINES /* to get M_PI, etc, on Windows */
45
46/* workaround if standard makefiles aren't used */
47#if !defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < 600
48#undef _XOPEN_SOURCE
49#define _XOPEN_SOURCE 600
50#endif
51
52#include <stdio.h>
53#include <math.h>
54
55#include "scip/scip.h"
56#include "scip/scipdefplugins.h"
57
58/* Model parameters */
59
60/** number of possible wire types */
61#define nwires 11
62
63/** diameters of available diameters (in) */
64static const SCIP_Real diameters[] = { 0.207, 0.225, 0.244, 0.263, 0.283, 0.307, 0.331, 0.362, 0.394, 0.4375, 0.500 };
65
66/** preload (lb) */
67static const SCIP_Real preload = 300;
68
69/** maximal working load (lb) */
70static const SCIP_Real maxworkload = 1000;
71
72/** maximal deflection (in) */
73static const SCIP_Real maxdeflect = 6;
74
75/** deflection from preload (in) */
76static const SCIP_Real deflectpreload = 1.25;
77
78/** maximal free length of spring (in) */
79static const SCIP_Real maxfreelen = 14.0;
80
81/** maximal coil diameter (in) */
82static const SCIP_Real maxcoildiam = 3.0;
83
84/** maximal shear stress */
85static const SCIP_Real maxshearstress = 189000.0;
86
87/** shear modulus of material */
88static const SCIP_Real shearmod = 11500000.0;
89
90
91/** sets up problem */
92static
93SCIP_RETCODE setupProblem(
94 SCIP* scip /**< SCIP data structure */
95 )
96{
97 SCIP_VAR* coil; /* coil diameter */
98 SCIP_VAR* wire; /* wire diameter */
99 SCIP_VAR* defl; /* deflection */
100 SCIP_VAR* ncoils; /* number of coils (integer) */
101 SCIP_VAR* const1; /* a constant */
102 SCIP_VAR* const2; /* another constant */
103 SCIP_VAR* volume; /* total volume */
104 SCIP_VAR* y[nwires]; /* wire choice (binary) */
105
106 SCIP_EXPR* coilexpr;
107 SCIP_EXPR* wireexpr;
108 SCIP_EXPR* deflexpr;
109 SCIP_EXPR* ncoilsexpr;
110 SCIP_EXPR* const1expr;
111 SCIP_EXPR* const2expr;
112 SCIP_EXPR* volumeexpr;
113
114 SCIP_CONS* voldef;
115 SCIP_CONS* defconst1;
116 SCIP_CONS* defconst2;
117 SCIP_CONS* shear;
118 SCIP_CONS* defdefl;
119 SCIP_CONS* freel;
120 SCIP_CONS* coilwidth;
121 SCIP_CONS* defwire;
122 SCIP_CONS* selectwire;
123
124 char name[SCIP_MAXSTRLEN];
125 int i;
126
127 /* create empty problem */
128 SCIP_CALL( SCIPcreateProbBasic(scip, "spring") );
129
130 /* create variables */
131 SCIP_CALL( SCIPcreateVarBasic(scip, &coil, "coildiam", 0.0, SCIPinfinity(scip), 0.0, SCIP_VARTYPE_CONTINUOUS) );
132 SCIP_CALL( SCIPcreateVarBasic(scip, &wire, "wirediam", 0.0, SCIPinfinity(scip), 0.0, SCIP_VARTYPE_CONTINUOUS) );
133 SCIP_CALL( SCIPcreateVarBasic(scip, &defl, "deflection", 0.0, SCIPinfinity(scip), 0.0, SCIP_VARTYPE_CONTINUOUS) );
134 SCIP_CALL( SCIPcreateVarBasic(scip, &ncoils, "ncoils", 0.0, SCIPinfinity(scip), 0.0, SCIP_VARTYPE_INTEGER) );
135 SCIP_CALL( SCIPcreateVarBasic(scip, &const1, "const1", 0.0, SCIPinfinity(scip), 0.0, SCIP_VARTYPE_CONTINUOUS) );
136 SCIP_CALL( SCIPcreateVarBasic(scip, &const2, "const2", 0.0, SCIPinfinity(scip), 0.0, SCIP_VARTYPE_CONTINUOUS) );
137 SCIP_CALL( SCIPcreateVarBasic(scip, &volume, "volume", 0.0, SCIPinfinity(scip), 1.0, SCIP_VARTYPE_CONTINUOUS) );
138 for( i = 0; i < nwires; ++i )
139 {
140 (void) SCIPsnprintf(name, SCIP_MAXSTRLEN, "wire%d", i+1);
141 SCIP_CALL( SCIPcreateVarBasic(scip, &y[i], name, 0.0, 1.0, 0.0, SCIP_VARTYPE_BINARY) );
142 }
143
144 /* set nonstandard variable bounds */
145 SCIP_CALL( SCIPchgVarLb(scip, defl, deflectpreload / (maxworkload - preload)) );
146 SCIP_CALL( SCIPchgVarUb(scip, defl, maxdeflect / preload) );
147
148 /* add variables to problem */
149 SCIP_CALL( SCIPaddVar(scip, coil) );
150 SCIP_CALL( SCIPaddVar(scip, wire) );
151 SCIP_CALL( SCIPaddVar(scip, defl) );
152 SCIP_CALL( SCIPaddVar(scip, ncoils) );
153 SCIP_CALL( SCIPaddVar(scip, const1) );
154 SCIP_CALL( SCIPaddVar(scip, const2) );
155 SCIP_CALL( SCIPaddVar(scip, volume) );
156 for( i = 0; i < nwires; ++i )
157 {
158 SCIP_CALL( SCIPaddVar(scip, y[i]) );
159 }
160
161 /* create variable expressions */
162 SCIP_CALL( SCIPcreateExprVar(scip, &coilexpr, coil, NULL, NULL) );
163 SCIP_CALL( SCIPcreateExprVar(scip, &wireexpr, wire, NULL, NULL) );
164 SCIP_CALL( SCIPcreateExprVar(scip, &deflexpr, defl, NULL, NULL) );
165 SCIP_CALL( SCIPcreateExprVar(scip, &ncoilsexpr, ncoils, NULL, NULL) );
166 SCIP_CALL( SCIPcreateExprVar(scip, &const1expr, const1, NULL, NULL) );
167 SCIP_CALL( SCIPcreateExprVar(scip, &const2expr, const2, NULL, NULL) );
168 SCIP_CALL( SCIPcreateExprVar(scip, &volumeexpr, volume, NULL, NULL) );
169
170 /* nonlinear constraint voldef: PI/2 * (ncoils+2)*coil*wire^2 - volume == 0 */
171 {
172 SCIP_EXPR* exprs[3];
173 SCIP_EXPR* powexpr;
174 SCIP_EXPR* prodexpr;
175 SCIP_EXPR* sumexpr;
176 SCIP_EXPR* expr;
177 SCIP_Real coefs[2];
178
179 /* create wire^2 */
180 SCIP_CALL( SCIPcreateExprPow(scip, &powexpr, wireexpr, 2.0, NULL, NULL) );
181
182 /* create (ncoils+2) */
183 SCIP_CALL( SCIPcreateExprSum(scip, &sumexpr, 1, &ncoilsexpr, NULL, 2.0, NULL, NULL) );
184
185 /* create (ncoils+2)*coil*wire^2 */
186 exprs[0] = sumexpr;
187 exprs[1] = coilexpr;
188 exprs[2] = powexpr;
189 SCIP_CALL( SCIPcreateExprProduct(scip, &prodexpr, 3, exprs, 1.0, NULL, NULL) );
190
191 /* create PI/2 * (ncoils+2)*coil*wire^2 - volume */
192 exprs[0] = prodexpr;
193 coefs[0] = M_PI_2;
194 exprs[1] = volumeexpr;
195 coefs[1] = -1.0;
196 SCIP_CALL( SCIPcreateExprSum(scip, &expr, 2, exprs, coefs, 0.0, NULL, NULL) );
197
198 /* create nonlinear constraint */
199 SCIP_CALL( SCIPcreateConsBasicNonlinear(scip, &voldef, "voldef", expr, 0.0, 0.0) );
200
201 /* release expressions */
202 SCIP_CALL( SCIPreleaseExpr(scip, &expr) );
203 SCIP_CALL( SCIPreleaseExpr(scip, &prodexpr) );
204 SCIP_CALL( SCIPreleaseExpr(scip, &sumexpr) );
205 SCIP_CALL( SCIPreleaseExpr(scip, &powexpr) );
206 }
207
208 /* nonlinear constraint defconst1: coil / wire - const1 == 0.0 */
209 {
210 SCIP_EXPR* exprs[2];
211 SCIP_EXPR* powexpr;
212 SCIP_EXPR* prodexpr;
213 SCIP_EXPR* sumexpr;
214 SCIP_Real coefs[2];
215
216 /* create 1 / wire */
217 SCIP_CALL( SCIPcreateExprPow(scip, &powexpr, wireexpr, -1.0, NULL, NULL) );
218
219 /* create coil / wire */
220 exprs[0] = coilexpr;
221 exprs[1] = powexpr;
222 SCIP_CALL( SCIPcreateExprProduct(scip, &prodexpr, 2, exprs, 1.0, NULL, NULL) );
223
224 /* create coil / wire - const1 */
225 exprs[0] = prodexpr;
226 coefs[0] = 1.0;
227 exprs[1] = const1expr;
228 coefs[1] = -1.0;
229 SCIP_CALL( SCIPcreateExprSum(scip, &sumexpr, 2, exprs, coefs, 0.0, NULL, NULL) );
230
231 /* create nonlinear constraint */
232 SCIP_CALL( SCIPcreateConsBasicNonlinear(scip, &defconst1, "defconst1", sumexpr, 0.0, 0.0) );
233
234 /* release expressions */
235 SCIP_CALL( SCIPreleaseExpr(scip, &sumexpr) );
236 SCIP_CALL( SCIPreleaseExpr(scip, &prodexpr) );
237 SCIP_CALL( SCIPreleaseExpr(scip, &powexpr) );
238 }
239
240 /* nonlinear constraint defconst2: (4.0 * const1 - 1.0) / (4.0 * const1 - 4.0) + 0.615 / const1 - const2 == 0.0 */
241 {
242 SCIP_EXPR* exprs[3];
243 SCIP_EXPR* sumexpr1;
244 SCIP_EXPR* sumexpr2;
245 SCIP_EXPR* powexpr1;
246 SCIP_EXPR* powexpr2;
247 SCIP_EXPR* prodexpr;
248 SCIP_EXPR* expr;
249 SCIP_Real coefs[3];
250
251 /* create (4.0 * const1 - 1.0) */
252 coefs[0] = 4.0;
253 SCIP_CALL( SCIPcreateExprSum(scip, &sumexpr1, 1, &const1expr, coefs, -1.0, NULL, NULL) );
254
255 /* create (4.0 * const1 - 4.0) */
256 coefs[0] = 4.0;
257 SCIP_CALL( SCIPcreateExprSum(scip, &sumexpr2, 1, &const1expr, coefs, -4.0, NULL, NULL) );
258
259 /* create 1 / (4.0 * const1 - 4.0) */
260 SCIP_CALL( SCIPcreateExprPow(scip, &powexpr1, sumexpr2, -1.0, NULL, NULL) );
261
262 /* create (4.0 * const1 - 1.0) / (4.0 * const1 - 4.0) */
263 exprs[0] = sumexpr1;
264 exprs[1] = powexpr1;
265 SCIP_CALL( SCIPcreateExprProduct(scip, &prodexpr, 2, exprs, 1.0, NULL, NULL) );
266
267 /* create 1 / const1 */
268 SCIP_CALL( SCIPcreateExprPow(scip, &powexpr2, const1expr, -1.0, NULL, NULL) );
269
270 /* create (4.0 * const1 - 1.0) / (4.0 * const1 - 4.0) + 0.615 / const1 - const2 */
271 exprs[0] = prodexpr;
272 coefs[0] = 1.0;
273 exprs[1] = powexpr2;
274 coefs[1] = 0.615;
275 exprs[2] = const2expr;
276 coefs[2] = -1.0;
277 SCIP_CALL( SCIPcreateExprSum(scip, &expr, 3, exprs, coefs, 0.0, NULL, NULL) );
278
279 /* create nonlinear constraint */
280 SCIP_CALL( SCIPcreateConsBasicNonlinear(scip, &defconst2, "defconst2", expr, 0.0, 0.0) );
281
282 /* release expressions */
283 SCIP_CALL( SCIPreleaseExpr(scip, &expr) );
284 SCIP_CALL( SCIPreleaseExpr(scip, &powexpr2) );
285 SCIP_CALL( SCIPreleaseExpr(scip, &prodexpr) );
286 SCIP_CALL( SCIPreleaseExpr(scip, &powexpr1) );
287 SCIP_CALL( SCIPreleaseExpr(scip, &sumexpr2) );
288 SCIP_CALL( SCIPreleaseExpr(scip, &sumexpr1) );
289 }
290
291 /* quadratic constraint shear: 8.0*maxworkload/PI * const1 * const2 - maxshearstress * wire^2 <= 0.0 */
292 {
293 SCIP_VAR* quadvars1[2] = {const1, wire};
294 SCIP_VAR* quadvars2[2] = {const2, wire};
295 SCIP_Real quadcoefs[2] = {8.0 * maxworkload / M_PI, -maxshearstress};
296
297 /* create empty quadratic constraint with right-hand-side 0.0 */
298 SCIP_CALL( SCIPcreateConsQuadraticNonlinear(scip, &shear, "shear", 0, NULL, NULL, 2, quadvars1, quadvars2, quadcoefs,
299 -SCIPinfinity(scip), 0.0, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE, FALSE) );
300 }
301
302 /* nonlinear constraint defdefl: 8.0/shearmod * ncoils * const1^3 / wire - defl == 0.0 */
303 {
304 SCIP_EXPR* exprs[3];
305 SCIP_EXPR* prodexpr;
306 SCIP_EXPR* powexpr1;
307 SCIP_EXPR* powexpr2;
308 SCIP_EXPR* expr;
309 SCIP_Real coefs[3];
310
311 /* create const1^3 */
312 SCIP_CALL( SCIPcreateExprPow(scip, &powexpr1, const1expr, 3.0, NULL, NULL) );
313
314 /* create 1 / wire */
315 SCIP_CALL( SCIPcreateExprPow(scip, &powexpr2, wireexpr, -1.0, NULL, NULL) );
316
317 /* create ncoils * const1^3 / wire */
318 exprs[0] = ncoilsexpr;
319 exprs[1] = powexpr1;
320 exprs[2] = powexpr2;
321 SCIP_CALL( SCIPcreateExprProduct(scip, &prodexpr, 3, exprs, 1.0, NULL, NULL) );
322
323 /* create 8.0/shearmod * ncoils * const1^3 / wire - defl */
324 exprs[0] = prodexpr;
325 coefs[0] = 8.0 / shearmod;
326 exprs[1] = deflexpr;
327 coefs[1] = -1.0;
328 SCIP_CALL( SCIPcreateExprSum(scip, &expr, 2, exprs, coefs, 0.0, NULL, NULL) );
329
330 /* create nonlinear constraint */
331 SCIP_CALL( SCIPcreateConsBasicNonlinear(scip, &defdefl, "defdefl", expr, 0.0, 0.0) );
332
333 /* release expressions */
334 SCIP_CALL( SCIPreleaseExpr(scip, &expr) );
335 SCIP_CALL( SCIPreleaseExpr(scip, &prodexpr) );
336 SCIP_CALL( SCIPreleaseExpr(scip, &powexpr2) );
337 SCIP_CALL( SCIPreleaseExpr(scip, &powexpr1) );
338 }
339
340 /* quadratic constraint freel: maxworkload * defl + 1.05 * ncoils * wire + 2.1 * wire <= maxfreelen */
341 {
342 SCIP_VAR* linvars[2] = {defl, wire};
343 SCIP_Real lincoefs[2] = {maxworkload, 2.1};
344 SCIP_Real one05 = 1.05;
345
346 /* create quadratic constraint maxworkload * defl + 1.05 * ncoils * wire <= maxfreelen */
347 SCIP_CALL( SCIPcreateConsQuadraticNonlinear(scip, &freel, "freel", 2, linvars, lincoefs, 1, &ncoils, &wire, &one05,
348 -SCIPinfinity(scip), maxfreelen, TRUE, TRUE, TRUE, TRUE, TRUE, FALSE, FALSE,
349 FALSE, FALSE) );
350 }
351
352 /* linear constraint coilwidth: coil + wire <= maxcoildiam */
353 {
354 /* create empty linear constraint with right-hand-side maxcoildiam */
355 SCIP_CALL( SCIPcreateConsBasicLinear(scip, &coilwidth, "coilwidth", 0, NULL, NULL, -SCIPinfinity(scip), maxcoildiam) );
356
357 /* add linear term coil + wire */
358 SCIP_CALL( SCIPaddCoefLinear(scip, coilwidth, coil, 1.0) );
359 SCIP_CALL( SCIPaddCoefLinear(scip, coilwidth, wire, 1.0) );
360 }
361
362 /* linear constraint defwire: sum_i b[i]*y[i] - wire == 0.0 */
363 {
364 /* create linear constraint sum_i b[i]*y[i] == 0.0 */
365 SCIP_CALL( SCIPcreateConsBasicLinear(scip, &defwire, "defwire", nwires, y, (SCIP_Real*)diameters, 0.0, 0.0) );
366
367 /* add term -wire */
368 SCIP_CALL( SCIPaddCoefLinear(scip, defwire, wire, -1.0) );
369 }
370
371 /* specialized linear constraint selectwire: sum_i y[i] == 1.0 */
372 {
373 SCIP_CALL( SCIPcreateConsBasicSetpart(scip, &selectwire, "selectwire", nwires, y) );
374 }
375
376 /* add constraints to problem */
377 SCIP_CALL( SCIPaddCons(scip, voldef) );
378 SCIP_CALL( SCIPaddCons(scip, defconst1) );
379 SCIP_CALL( SCIPaddCons(scip, defconst2) );
380 SCIP_CALL( SCIPaddCons(scip, shear) );
381 SCIP_CALL( SCIPaddCons(scip, defdefl) );
382 SCIP_CALL( SCIPaddCons(scip, freel) );
383 SCIP_CALL( SCIPaddCons(scip, coilwidth) );
384 SCIP_CALL( SCIPaddCons(scip, defwire) );
385 SCIP_CALL( SCIPaddCons(scip, selectwire) );
386
387 /* release variable expressions */
388 SCIP_CALL( SCIPreleaseExpr(scip, &volumeexpr) );
389 SCIP_CALL( SCIPreleaseExpr(scip, &const2expr) );
390 SCIP_CALL( SCIPreleaseExpr(scip, &const1expr) );
391 SCIP_CALL( SCIPreleaseExpr(scip, &ncoilsexpr) );
392 SCIP_CALL( SCIPreleaseExpr(scip, &deflexpr) );
393 SCIP_CALL( SCIPreleaseExpr(scip, &wireexpr) );
394 SCIP_CALL( SCIPreleaseExpr(scip, &coilexpr) );
395
396 /* release variables and constraints
397 * the problem has them captured, and we do not require them anymore
398 */
399 SCIP_CALL( SCIPreleaseVar(scip, &coil) );
400 SCIP_CALL( SCIPreleaseVar(scip, &wire) );
401 SCIP_CALL( SCIPreleaseVar(scip, &defl) );
402 SCIP_CALL( SCIPreleaseVar(scip, &ncoils) );
403 SCIP_CALL( SCIPreleaseVar(scip, &const1) );
404 SCIP_CALL( SCIPreleaseVar(scip, &const2) );
405 SCIP_CALL( SCIPreleaseVar(scip, &volume) );
406 for( i = 0; i < nwires; ++i )
407 {
408 SCIP_CALL( SCIPreleaseVar(scip, &y[i]) );
409 }
410
411 SCIP_CALL( SCIPreleaseCons(scip, &voldef) );
412 SCIP_CALL( SCIPreleaseCons(scip, &defconst1) );
413 SCIP_CALL( SCIPreleaseCons(scip, &defconst2) );
414 SCIP_CALL( SCIPreleaseCons(scip, &shear) );
415 SCIP_CALL( SCIPreleaseCons(scip, &defdefl) );
416 SCIP_CALL( SCIPreleaseCons(scip, &freel) );
417 SCIP_CALL( SCIPreleaseCons(scip, &coilwidth) );
418 SCIP_CALL( SCIPreleaseCons(scip, &defwire) );
419 SCIP_CALL( SCIPreleaseCons(scip, &selectwire) );
420
421 return SCIP_OKAY;
422}
423
424/** runs spring example */
425static
426SCIP_RETCODE runSpring(void)
427{
428 SCIP* scip;
429
430 SCIP_CALL( SCIPcreate(&scip) );
431 SCIP_CALL( SCIPincludeDefaultPlugins(scip) );
432
433 SCIPinfoMessage(scip, NULL, "\n");
434 SCIPinfoMessage(scip, NULL, "************************************************\n");
435 SCIPinfoMessage(scip, NULL, "* Running Coil Compression Spring Design Model *\n");
436 SCIPinfoMessage(scip, NULL, "************************************************\n");
437 SCIPinfoMessage(scip, NULL, "\n");
438
439 SCIP_CALL( setupProblem(scip) );
440
441 SCIPinfoMessage(scip, NULL, "Original problem:\n");
442 SCIP_CALL( SCIPprintOrigProblem(scip, NULL, "cip", FALSE) );
443
444 SCIPinfoMessage(scip, NULL, "\n");
445 SCIP_CALL( SCIPpresolve(scip) );
446
447 /* SCIPinfoMessage(scip, NULL, "Reformulated problem:\n");
448 SCIP_CALL( SCIPprintTransProblem(scip, NULL, "cip", FALSE) );
449 */
450
451 SCIPinfoMessage(scip, NULL, "\nSolving...\n");
452 SCIP_CALL( SCIPsolve(scip) );
453
454 if( SCIPgetNSols(scip) > 0 )
455 {
456 SCIPinfoMessage(scip, NULL, "\nSolution:\n");
457 SCIP_CALL( SCIPprintSol(scip, SCIPgetBestSol(scip), NULL, FALSE) );
458 }
459
460 SCIP_CALL( SCIPfree(&scip) );
461
462 return SCIP_OKAY;
463}
464
465
466/** main method starting SCIP */
467int main(
468 int argc, /**< number of arguments from the shell */
469 char** argv /**< array of shell arguments */
470 )
471{ /*lint --e{715}*/
472 SCIP_RETCODE retcode;
473
474 retcode = runSpring();
475
476 /* evaluate return code of the SCIP process */
477 if( retcode != SCIP_OKAY )
478 {
479 /* write error back trace */
480 SCIPprintError(retcode);
481 return -1;
482 }
483
484 return 0;
485}
y
SCIP_VAR ** y
Definition: circlepacking.c:64
NULL
#define NULL
Definition: def.h:267
SCIP_MAXSTRLEN
#define SCIP_MAXSTRLEN
Definition: def.h:288
SCIP_Real
#define SCIP_Real
Definition: def.h:173
TRUE
#define TRUE
Definition: def.h:93
FALSE
#define FALSE
Definition: def.h:94
SCIP_CALL
#define SCIP_CALL(x)
Definition: def.h:374
SCIPcreateConsBasicSetpart
SCIP_RETCODE SCIPcreateConsBasicSetpart(SCIP *scip, SCIP_CONS **cons, const char *name, int nvars, SCIP_VAR **vars)
Definition: cons_setppc.c:9391
SCIPaddCoefLinear
SCIP_RETCODE SCIPaddCoefLinear(SCIP *scip, SCIP_CONS *cons, SCIP_VAR *var, SCIP_Real val)
Definition: cons_linear.c:18207
SCIPcreateConsBasicLinear
SCIP_RETCODE SCIPcreateConsBasicLinear(SCIP *scip, SCIP_CONS **cons, const char *name, int nvars, SCIP_VAR **vars, SCIP_Real *vals, SCIP_Real lhs, SCIP_Real rhs)
Definition: cons_linear.c:18055
SCIPcreateConsBasicNonlinear
SCIP_RETCODE SCIPcreateConsBasicNonlinear(SCIP *scip, SCIP_CONS **cons, const char *name, SCIP_EXPR *expr, SCIP_Real lhs, SCIP_Real rhs)
Definition: cons_nonlinear.c:12718
SCIPcreateConsQuadraticNonlinear
SCIP_RETCODE SCIPcreateConsQuadraticNonlinear(SCIP *scip, SCIP_CONS **cons, const char *name, int nlinvars, SCIP_VAR **linvars, SCIP_Real *lincoefs, int nquadterms, SCIP_VAR **quadvars1, SCIP_VAR **quadvars2, SCIP_Real *quadcoefs, SCIP_Real lhs, SCIP_Real rhs, SCIP_Bool initial, SCIP_Bool separate, SCIP_Bool enforce, SCIP_Bool check, SCIP_Bool propagate, SCIP_Bool local, SCIP_Bool modifiable, SCIP_Bool dynamic, SCIP_Bool removable)
Definition: cons_nonlinear.c:12737
SCIPcreateExprVar
SCIP_RETCODE SCIPcreateExprVar(SCIP *scip, SCIP_EXPR **expr, SCIP_VAR *var, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
Definition: expr_var.c:390
SCIPcreateExprProduct
SCIP_RETCODE SCIPcreateExprProduct(SCIP *scip, SCIP_EXPR **expr, int nchildren, SCIP_EXPR **children, SCIP_Real coefficient, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
Definition: expr_product.c:2275
SCIPcreateExprSum
SCIP_RETCODE SCIPcreateExprSum(SCIP *scip, SCIP_EXPR **expr, int nchildren, SCIP_EXPR **children, SCIP_Real *coefficients, SCIP_Real constant, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
Definition: expr_sum.c:1114
SCIPcreateExprPow
SCIP_RETCODE SCIPcreateExprPow(SCIP *scip, SCIP_EXPR **expr, SCIP_EXPR *child, SCIP_Real exponent, SCIP_DECL_EXPR_OWNERCREATE((*ownercreate)), void *ownercreatedata)
Definition: expr_pow.c:3193
SCIPfree
SCIP_RETCODE SCIPfree(SCIP **scip)
Definition: scip_general.c:339
SCIPcreate
SCIP_RETCODE SCIPcreate(SCIP **scip)
Definition: scip_general.c:307
SCIPaddVar
SCIP_RETCODE SCIPaddVar(SCIP *scip, SCIP_VAR *var)
Definition: scip_prob.c:1668
SCIPaddCons
SCIP_RETCODE SCIPaddCons(SCIP *scip, SCIP_CONS *cons)
Definition: scip_prob.c:2770
SCIPcreateProbBasic
SCIP_RETCODE SCIPcreateProbBasic(SCIP *scip, const char *name)
Definition: scip_prob.c:180
SCIPinfoMessage
void SCIPinfoMessage(SCIP *scip, FILE *file, const char *formatstr,...)
Definition: scip_message.c:208
SCIPprintError
void SCIPprintError(SCIP_RETCODE retcode)
Definition: scip_general.c:221
SCIPreleaseCons
SCIP_RETCODE SCIPreleaseCons(SCIP *scip, SCIP_CONS **cons)
Definition: scip_cons.c:1174
SCIPreleaseExpr
SCIP_RETCODE SCIPreleaseExpr(SCIP *scip, SCIP_EXPR **expr)
Definition: scip_expr.c:1417
SCIPgetBestSol
SCIP_SOL * SCIPgetBestSol(SCIP *scip)
Definition: scip_sol.c:2169
SCIPprintSol
SCIP_RETCODE SCIPprintSol(SCIP *scip, SCIP_SOL *sol, FILE *file, SCIP_Bool printzeros)
Definition: scip_sol.c:1631
SCIPgetNSols
int SCIPgetNSols(SCIP *scip)
Definition: scip_sol.c:2070
SCIPpresolve
SCIP_RETCODE SCIPpresolve(SCIP *scip)
Definition: scip_solve.c:2328
SCIPsolve
SCIP_RETCODE SCIPsolve(SCIP *scip)
Definition: scip_solve.c:2498
SCIPprintOrigProblem
SCIP_RETCODE SCIPprintOrigProblem(SCIP *scip, FILE *file, const char *extension, SCIP_Bool genericnames)
Definition: scip_solvingstats.c:2371
SCIPinfinity
SCIP_Real SCIPinfinity(SCIP *scip)
Definition: scip_numerics.c:510
SCIPchgVarLb
SCIP_RETCODE SCIPchgVarLb(SCIP *scip, SCIP_VAR *var, SCIP_Real newbound)
Definition: scip_var.c:4676
SCIPchgVarUb
SCIP_RETCODE SCIPchgVarUb(SCIP *scip, SCIP_VAR *var, SCIP_Real newbound)
Definition: scip_var.c:4766
SCIPreleaseVar
SCIP_RETCODE SCIPreleaseVar(SCIP *scip, SCIP_VAR **var)
Definition: scip_var.c:1248
SCIPcreateVarBasic
SCIP_RETCODE SCIPcreateVarBasic(SCIP *scip, SCIP_VAR **var, const char *name, SCIP_Real lb, SCIP_Real ub, SCIP_Real obj, SCIP_VARTYPE vartype)
Definition: scip_var.c:194
SCIPsnprintf
int SCIPsnprintf(char *t, int len, const char *s,...)
Definition: misc.c:10877
M_PI
#define M_PI
Definition: pricer_rpa.c:97
scip.h
SCIP callable library.
SCIPincludeDefaultPlugins
SCIP_RETCODE SCIPincludeDefaultPlugins(SCIP *scip)
Definition: scipdefplugins.c:37
scipdefplugins.h
default SCIP plugins
setupProblem
static SCIP_RETCODE setupProblem(SCIP *scip)
Definition: spring.c:93
diameters
static const SCIP_Real diameters[]
Definition: spring.c:64
maxworkload
static const SCIP_Real maxworkload
Definition: spring.c:70
runSpring
static SCIP_RETCODE runSpring(void)
Definition: spring.c:426
main
int main(int argc, char **argv)
Definition: spring.c:467
nwires
#define nwires
Definition: spring.c:61
maxfreelen
static const SCIP_Real maxfreelen
Definition: spring.c:79
maxcoildiam
static const SCIP_Real maxcoildiam
Definition: spring.c:82
maxshearstress
static const SCIP_Real maxshearstress
Definition: spring.c:85
shearmod
static const SCIP_Real shearmod
Definition: spring.c:88
deflectpreload
static const SCIP_Real deflectpreload
Definition: spring.c:76
maxdeflect
static const SCIP_Real maxdeflect
Definition: spring.c:73
preload
static const SCIP_Real preload
Definition: spring.c:67
SCIP_Cons
Definition: struct_cons.h:47
SCIP_Expr
Definition: struct_expr.h:106
SCIP_Var
Definition: struct_var.h:208
SCIP_OKAY
@ SCIP_OKAY
Definition: type_retcode.h:42
SCIP_RETCODE
enum SCIP_Retcode SCIP_RETCODE
Definition: type_retcode.h:63
SCIP_VARTYPE_INTEGER
@ SCIP_VARTYPE_INTEGER
Definition: type_var.h:63
SCIP_VARTYPE_CONTINUOUS
@ SCIP_VARTYPE_CONTINUOUS
Definition: type_var.h:71
SCIP_VARTYPE_BINARY
@ SCIP_VARTYPE_BINARY
Definition: type_var.h:62