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--></style></head><body lang=DE><div class=WordSection1><p class=MsoNormal>Dear Scip Team,</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>For a Controller I am solving a non-convex Mixed Integer Nonlinear Program (MINLP) </p><p class=MsoNormal>in Matlab via the Opti Toolbox with the solver SCIP. </p><p class=MsoNormal>Depending on a choosen Horizon it can contain from 8 to 8000 binary variables, </p><p class=MsoNormal>16-16000 continous variables, 12-12000 equality constraints, 20-20000 inequality constraints,</p><p class=MsoNormal>24-24000 box constraints and 0 nonlinear constraints.</p><p class=MsoNormal>Due to some insight of the model I can construct an initial feasible vector x0</p><p class=MsoNormal>to start the Optimization. The problem is that the solver does not use the initial feasible </p><p class=MsoNormal>vector for an initial guess in the optimization.</p><p class=MsoNormal>It starts with an initial primal bound of NaN and a Gap of Infinity.</p><p class=MsoNormal>Due to this problem I cannot give the solver for example a warmstart solution.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Is it somehow possible to give the scip solver an initial guess for the</p><p class=MsoNormal>optimization problem and respectively an initial primal bound before solving? </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I have attached the result log of the problem below, if it helps to understand my question.</p><p class=MsoNormal>In the above given example I specified the limit of solutions to 1.</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>presolving:</p><p class=MsoNormal>(round 1, fast) 703 del vars, 1507 del conss, 0 add conss, 208 chg bounds, 0 chg sides, 100 chg coeffs, 0 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 2, fast) 704 del vars, 1607 del conss, 0 add conss, 377 chg bounds, 0 chg sides, 100 chg coeffs, 0 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 3, fast) 704 del vars, 1607 del conss, 198 add conss, 377 chg bounds, 0 chg sides, 100 chg coeffs, 0 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 4, fast) 704 del vars, 1607 del conss, 198 add conss, 773 chg bounds, 0 chg sides, 100 chg coeffs, 1 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 5, fast) 704 del vars, 1607 del conss, 396 add conss, 773 chg bounds, 0 chg sides, 100 chg coeffs, 1 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 6, fast) 704 del vars, 1607 del conss, 396 add conss, 773 chg bounds, 0 chg sides, 100 chg coeffs, 199 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 7, fast) 704 del vars, 1607 del conss, 495 add conss, 773 chg bounds, 0 chg sides, 100 chg coeffs, 298 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 8, exhaustive) 704 del vars, 1706 del conss, 891 add conss, 773 chg bounds, 0 chg sides, 100 chg coeffs, 298 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 9, fast) 704 del vars, 1706 del conss, 891 add conss, 1070 chg bounds, 0 chg sides, 100 chg coeffs, 298 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 10, exhaustive) 704 del vars, 1706 del conss, 891 add conss, 1070 chg bounds, 0 chg sides, 100 chg coeffs, 1294 upgd conss, 200 impls, 398 clqs</p><p class=MsoNormal>(round 11, exhaustive) 704 del vars, 2300 del conss, 1089 add conss, 1070 chg bounds, 0 chg sides, 100 chg coeffs, 1294 upgd conss, 589 impls, 398 clqs</p><p class=MsoNormal>(round 12, exhaustive) 704 del vars, 2300 del conss, 1089 add conss, 1070 chg bounds, 0 chg sides, 100 chg coeffs, 1494 upgd conss, 589 impls, 398 clqs</p><p class=MsoNormal> (1.8s) probing cycle finished: starting next cycle</p><p class=MsoNormal>(round 13, exhaustive) 704 del vars, 2300 del conss, 1089 add conss, 1209 chg bounds, 0 chg sides, 100 chg coeffs, 1494 upgd conss, 1149 impls, 688 clqs</p><p class=MsoNormal>(round 14, fast) 704 del vars, 2300 del conss, 1089 add conss, 1209 chg bounds, 39 chg sides, 139 chg coeffs, 1494 upgd conss, 1149 impls, 688 clqs</p><p class=MsoNormal> (1.9s) probing: 49/600 (8.2) - 0 fixings, 0 aggregations, 839 implications, 139 bound changes</p><p class=MsoNormal> (1.9s) probing aborted: 50/50 successive totally useless probings</p><p class=MsoNormal>presolving (15 rounds: 15 fast, 6 medium, 6 exhaustive):</p><p class=MsoNormal>704 deleted vars, 2300 deleted constraints, 1089 added constraints, 1209 tightened bounds, 0 added holes, 39 changed sides, 139 changed coefficients</p><p class=MsoNormal>1149 implications, 688 cliques</p><p class=MsoNormal>presolved problem has 2093 variables (600 bin, 0 int, 0 impl, 1493 cont) and 1893 constraints</p><p class=MsoNormal> 297 constraints of type <soc></p><p class=MsoNormal> 600 constraints of type <varbound></p><p class=MsoNormal> 2 constraints of type <setppc></p><p class=MsoNormal> 198 constraints of type <and></p><p class=MsoNormal> 399 constraints of type <linear></p><p class=MsoNormal> 199 constraints of type <quadratic></p><p class=MsoNormal> 198 constraints of type <nonlinear></p><p class=MsoNormal>Presolving Time: 1.91</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>******************************************************************************</p><p class=MsoNormal>This program contains Ipopt, a library for large-scale nonlinear optimization.</p><p class=MsoNormal>Ipopt is released as open source code under the Eclipse Public License (EPL).</p><p class=MsoNormal> For more information visit http://projects.coin-or.org/Ipopt</p><p class=MsoNormal>******************************************************************************</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons |cols |rows |cuts |confs|strbr| dualbound | primalbound | gap </p><p class=MsoNormal> 2.4s| 1 | 0 | 3490 | - | 27M| 0 | 84 |2093 |1893 |2093 |2393 | 0 | 0 | 0 |-6.537019e+00 | -- | Inf </p><p class=MsoNormal> 2.5s| 1 | 0 | 3947 | - | 28M| 0 | 84 |2093 |1894 |2093 |2393 | 0 | 0 | 0 |-6.537019e+00 | -- | Inf </p><p class=MsoNormal> 2.5s| 1 | 0 | 4465 | - | 29M| 0 | 29 |2093 |1894 |2093 |2718 | 325 | 0 | 0 |-6.512983e+00 | -- | Inf </p><p class=MsoNormal> 2.6s| 1 | 0 | 4645 | - | 30M| 0 | 33 |2093 |1894 |2093 |2859 | 466 | 0 | 0 |-6.512907e+00 | -- | Inf </p><p class=MsoNormal> 2.6s| 1 | 0 | 5109 | - | 30M| 0 | 30 |2093 |1894 |2093 |2996 | 603 | 0 | 0 |-6.512515e+00 | -- | Inf </p><p class=MsoNormal> 2.7s| 1 | 0 | 6191 | - | 30M| 0 | 42 |2093 |1894 |2093 |3138 | 745 | 0 | 0 |-6.459440e+00 | -- | Inf </p><p class=MsoNormal> 2.8s| 1 | 0 | 8127 | - | 31M| 0 | 36 |2093 |1894 |2093 |3322 | 929 | 0 | 0 |-6.392400e+00 | -- | Inf </p><p class=MsoNormal> 2.9s| 1 | 0 | 9371 | - | 32M| 0 | 42 |2093 |1894 |2093 |3461 |1068 | 0 | 0 |-6.352951e+00 | -- | Inf </p><p class=MsoNormal> 3.1s| 1 | 0 | 10677 | - | 32M| 0 | 38 |2093 |1894 |2093 |3598 |1205 | 0 | 0 |-6.347719e+00 | -- | Inf </p><p class=MsoNormal> 3.1s| 1 | 0 | 10791 | - | 33M| 0 | 27 |2093 |1894 |2093 |3702 |1309 | 0 | 0 |-6.345305e+00 | -- | Inf </p><p class=MsoNormal> 3.2s| 1 | 0 | 10904 | - | 33M| 0 | 27 |2093 |1894 |2093 |3804 |1411 | 0 | 0 |-6.344332e+00 | -- | Inf </p><p class=MsoNormal> 3.2s| 1 | 0 | 11033 | - | 34M| 0 | 26 |2093 |1894 |2087 |3055 |1523 | 0 | 0 |-6.343795e+00 | -- | Inf </p><p class=MsoNormal> 3.3s| 1 | 0 | 11152 | - | 34M| 0 | 26 |2093 |1894 |2087 |3157 |1625 | 0 | 0 |-6.342783e+00 | -- | Inf </p><p class=MsoNormal> 3.3s| 1 | 0 | 11248 | - | 34M| 0 | 22 |2093 |1894 |2087 |3232 |1700 | 0 | 0 |-6.342678e+00 | -- | Inf </p><p class=MsoNormal> 3.4s| 1 | 0 | 11323 | - | 35M| 0 | 22 |2093 |1894 |2087 |3283 |1751 | 0 | 0 |-6.342664e+00 | -- | Inf </p><p class=MsoNormal> time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons |cols |rows |cuts |confs|strbr| dualbound | primalbound | gap </p><p class=MsoNormal> 3.4s| 1 | 0 | 11378 | - | 35M| 0 | 22 |2093 |1894 |2087 |3339 |1807 | 0 | 0 |-6.342662e+00 | -- | Inf </p><p class=MsoNormal> 3.4s| 1 | 0 | 11441 | - | 35M| 0 | 22 |2093 |1894 |2087 |2854 |1858 | 0 | 0 |-6.342651e+00 | -- | Inf </p><p class=MsoNormal> 3.5s| 1 | 0 | 11520 | - | 36M| 0 | 22 |2093 |1894 |2087 |2878 |1882 | 0 | 0 |-6.342549e+00 | -- | Inf </p><p class=MsoNormal> 3.5s| 1 | 0 | 11551 | - | 36M| 0 | 22 |2093 |1894 |2087 |2897 |1901 | 0 | 0 |-6.342548e+00 | -- | Inf </p><p class=MsoNormal> 3.5s| 1 | 0 | 11568 | - | 36M| 0 | 22 |2093 |1894 |2087 |2907 |1911 | 0 | 0 |-6.342548e+00 | -- | Inf </p><p class=MsoNormal> 3.5s| 1 | 0 | 11592 | - | 36M| 0 | 20 |2093 |1894 |2087 |2911 |1915 | 0 | 0 |-6.342545e+00 | -- | Inf </p><p class=MsoNormal> 3.6s| 1 | 0 | 11600 | - | 37M| 0 | 20 |2093 |1894 |2087 |2914 |1918 | 0 | 0 |-6.342545e+00 | -- | Inf </p><p class=MsoNormal> 3.6s| 1 | 0 | 11601 | - | 37M| 0 | 20 |2093 |1894 |2087 |2299 |1919 | 0 | 0 |-6.342545e+00 | -- | Inf </p><p class=MsoNormal> 3.6s| 1 | 0 | 11603 | - | 37M| 0 | 20 |2093 |1894 |2087 |2302 |1922 | 0 | 0 |-6.342545e+00 | -- | Inf </p><p class=MsoNormal> 10.9s| 1 | 2 | 11649 | - | 37M| 0 | 17 |2093 |1895 |2087 |2302 |1922 | 0 | 19 |-6.342545e+00 | -- | Inf </p><p class=MsoNormal>z17.6s| 5 | 6 | 12165 | 584.0 | 37M| 4 | 8 |2093 |1895 |2087 |2192 |2358 | 0 | 60 |-6.342545e+00 |-6.325721e+00 | 0.27</p><p class=MsoNormal>SCIP Status : solving was interrupted [solution limit reached]</p><p class=MsoNormal>Solving Time (sec) : 17.64</p><p class=MsoNormal>Solving Nodes : 5</p><p class=MsoNormal>Primal Bound : -6.32572075532809e+00 (1 solutions)</p><p class=MsoNormal>Dual Bound : -6.34254542284478e+00</p><p class=MsoNormal>Gap : 0.27 </p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Kind regards</p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Stephanos P.</p></div></body></html>