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Questions tagged [scip]

Software package for solving mixed integer linear and nonlinear programming problems and part of the SCIP Optimization Suite. SCIP is distributed under the Apache 2.0 license and its C source code is available.

Mixed integer programming is the task to optimize a linear functional over a polyhedron, where some or all variables are constrained to be integer. The SCIP Optimization suite offers a branch-and-cut implementation, and a standalone implementation of the Simplex algorithm, called SoPlex, to solve linear programming problems.

Furthermore, SCIP comes with a modelling language ZIMPL that aims to ease the task of formulating mixed integer programming problems, a parallel solver called UG, and an implementation of the branch-and-cut-and-price algorithm called GCG.

The SCIP Optimization suite is one of the fastest implementations whose source code is available. It is written in C, but also offers a C++ interface.

<= 03.11.2022:
  • SCIP is free for academic research and can be licensed for commercial use.
>= 04.11.2022:
  • SCIP (as well as SoPlex) is distributed under the Apache 2.0 license.
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Resetting priorities just before branching or customized branching rule

Given the node where the MIP solver is just about to pick a variable to branch, I would like to suggest a small subset of variables to chose from but leave breaking ties to the solver's heuristics. I have good reasons to believe that this can…
Ali
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compiling dynamic library on Mac: ld: symbol(s) not found for architecture x86_64

I'm working on compiling a SCIP dynamic library. SCIP is implemented in C, and our optimization project is all Java, so we're wanting to use JNA to access it. We've written a C++ wrapper to build the dynamic library, and I'm having issues compiling…
Geoff
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Solving SCIP syntax error

I have a small problem in which gurobi returns an error because Q matrix is not positive semi-definite (PSD). Minimize CAV_TDiff_LK_0_0 + CAV_TDiff_LK_0_1 + 0 TC_l_0_0 + 0 TC_lz1_0_1 Subject To CSTR_T_LK_0_1: CDV_T_EPS_L_0 +…
twfx
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Is it possible to have SCIP and and python-zibopt work under windows?

Recently I want to try some open source solvers instead of CPLEX. I found that PICOS + zibopt may be a good choice. However, I can merely find instruction on how to make zibopt work with python under windows properly. I downloaded the windows…
Zhifan Xu
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(mySQL/scip) How to avoid creating new columns in a database when variables have subscripts

Some background information: We use linear programming (scip/ZIMPL) to solve a optimization problem As a result variables have subscripts in the mathematical formulation Currently using mySQL/HeidiSQL for database/interface Currently we take the…
user4178091
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SCIP write best feasible solution in automated test

Based on steps in http://scip.zib.de/doc/html/TEST.php, I have managed to set up an automated test using SCIP. However, I'd like to write the solution (best feasible solution) to a file, instead of just getting the objective value. Is there anyway…
twfx
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Scip: Maximum time option missing?

I'm using a software based on SCIP (3.0.1). I have a bunch of experiments to execute, and for that I'd like to simply enforce a maximum execution time for SCIP: if you haven't already found the best solution, after x seconds outputs anyway the best…
user4165955
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Getting LP relaxation before SCIPsolve

I would like to use the LP relaxation of the problem before calling SCIPsolve() and I would like to know what is the best/simplest way of doing this. I'm currently creating a SCIP_LPI that I would like to populate with my original problem's data. I…
rocarvaj
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Speeding up Binary Integer programming model

Can anyone give me some tips to make a binary integer programming model faster? I currently have a model that runs well with very small amount of variables but as soon as I increase the number of variables in my model SCIP keeps running without…
migs
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Using SCIP C++ wrapper classes

Can someone please show me how to use the C++ wrapper classes for SCIP? I don't know how the Makefiles in the examples work. I tried simply using the command g++ -Wall example.cpp but when I do this it tells me that scip/scip.h: fatal error:…
migs
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How to pass a graph data structure to the subproblem in SCIP?

I have a question about branch and price in SCIP! I have a heuristic to solve my sub-problem, and the input to this heuristic is a bipartite graph. The structure of this graph is dependent on the variables fixing by branching rule, so it is…
Dani
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Get the Objective function value in SCIP

I am solving an Integer program model with SCIP and I need to store the objective function value. I was wondering how I can get the objective function value after solving the IP model? can someone help me?
Dani
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Computation time of LP Relaxation of an IP higher than optimizing the IP itself

This is a follow up of my previous question on LP Relaxation of a MIP using SCIP. Though I'm able to compute a LP Relaxation solution of my MIP by simply passing the MIP (in CPLEX format) to SoPlex, I observe that the computation time taken by…
Rohit Girdhar
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SCIP unmodified LP-bound

I am using SCIP 3.0.2 with cplex 12.6 as LP-solver. My model requires Column generation. I already implemented it in CPLEX but since CPLEX can only do CG in the root node I am using SCIP to do Branch-and-Price. In CPLEX it turned out to be…
user3611568
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error in running one of the SCIP's example

I have a problem with running the VRP example in the SCIP package, I follow the instruction provided in this link: http://scip.zib.de/doc/html/START.php but when I run "make" inside the created VRP directory, I got the following error: No rule to…
Dani
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