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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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Setting constraints with variables as exponents in PySCIPOpt

I want to solve an MINLP problem with SCIP in Python and therefore use PySCIPOpt. I already introduced the variables, the objective function, and set the constraints (as far as it was possible, given my issue). Within one constraint, there is a…
LukPau
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Is there a way to save the cutting planes from SCIP?

I am working on using SCIP to generate cutting planes for my project. I am doing so using a C++ code directly with default plugins included, modified from scip/examples/MIPsolver/src/cppmain. However the array of cutting planes is not saved. The…
Chia Teck Yan
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Creating several variables/constraints in one shot in SCIP

I have a C++ application that can use indistinctly (vía polymorphism and virtual methods) CPLEX, GUROBI or COIN to solve an LP, and now I'm adding support for SCIP. In the first three solvers I can add several constraints/variables at once, using…
Alvaro Palma Aste
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real gas, 1D pipe flow in Pyomo + SCIP failing through energy equation?

Hi there smart people! I am trying to implement a 1D, steady-state, real gas (compressibility factor) pipe flow model in Python using Pyomo + SCIP. It basically amounts to solving a DAE system. The formulation is an adopted version from chapter 10…
Tobias Triesch
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Best way to obtain the LP relaxation of a MIP using SCIP

I've a C++ app which can use indistinctively CPLEX or COIN, and now I want to add SCIP as a choice. As a part of the functionality, it's required to run the LP relaxation of a MIP problem. In CPLEX or COIN that's simple, I just create the problem…
Alvaro Palma Aste
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How to generate cutting planes for a SAT problem?

I am working on idea which requires me to generate cutting planes for SAT problems. I am using a problem from https://www.cs.ubc.ca/~hoos/SATLIB/benchm.html, qg5-10.cnf from SAT-encoded Quasigroup (or Latin square) instances. I am using the latest…
Chia Teck Yan
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Cplex giving wrong result

I created a sample test.lp file as follows: Maximize y Subject To +x1+100M+3M2+x4-y+A=0 x1-M-M2-10x4>=-20 x1 - 3 M + M2 <= 100 M - 3.5 x4 + M2= 0 A+x1<=140 Bounds x1<= 40 2 <= x4 <= 3 0<=x1 Binary M Integer A End Used all default…
Dr.PB
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Python Mozek optimization - nonlinear constraints

I am comparing SCIP and Mozek with a very simple optimization task, but I had a hard time to understand how to code for Mozek when constraints are nonlinear. For example: from pyscipopt import Model md = Model() x = md.addVar('x', lb=0, ub=5,…
Watchung
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Is there a way to add user data to the nodes in SCIP?

I am trying to add some user information to the nodes of the branch-and-cut tree in SCIP and when branching is performed on the node, I want the child nodes to inherit the same information as the parent. I can access the nodes via an event handler…
sbay
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Performance of SCIP: how many variables and constraints SCIP can deal with, and how much time SCIP will take on solving?

I'm new to SCIP, and I have a large-scale MINLP with about 500,000 integer variables, 500,000 linear constraints, and 100,000 nonlinear constraints. I read a lot of papers about the performance of SCIP, but can't find how many variables and…
Lynn
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How to use SCIPoptSuite with UG(FiberSCIP)?

I an using SCIPoptSuite in my code to solve a MINLP problem, and I would like to test if parallelization inproves the performance or not. However the UG Framework is not built in the SCIPoptSuite installer version, so I wonder if I can compile UG…
ZYberTanC
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How to use Soplex to solve problems with a zero objective function?

I am trying to use Soplex to solve a problem with zero objective function through C++ code, but I face an error. My main code is this: int main(int argc, char* argv[]) { if (argc <= 1 || argc >= 3) /*Anything <=1 or >=3 arguments in command line…
Chia Teck Yan
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Is SCIP safe to call from multiple threads?

We need to solve many different instances of a problem, where each problem is completely separate from the others. Is SCIP (SCIPsolve) safe to call from multiple threads this way? I did find some information on SCIPsolveParallel, but this appears to…
DanZee
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having problems with the tbb library while compiling the papillo package on macOS

I'm trying to install scip via the Scip Optimization Suite. I build scip with Cmake and the Cmake part works just fine. The following error occurs when I do the make command. Undefined symbols for architecture x86_64: …
Lisa Marie
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In pyscipopt, would it be possible to use a function containing an optimization model inside of my main optimization model?

I am using Jupyter Notebook. I have tried defining a function with an optimization model, it seems to work outside of my main model. When I tried using the function on a variable inside my main model, at first the kernel dies, when I have updated…
Denver Pascua
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