
Christian Perau
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Recent activity by Christian Perau-
Warm start LP with barrier
AnsweredI am working with very large models that I solve iteratively changing some coefficients or RHS values between the iterations. Due to memory consumption I always need to construct and deconstrcut th...
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Using -1 for lazy value gives wrong result
AnsweredHello, I recently integrated lazy constraints into my model. I just tried out some parametrization and especially the value for the Lazy attribute of the constraints I want to specify as such (in ...
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Convert presolved model to original model
AnsweredI am working with rather big models. After the presolve (during the ordering) I notice the highest peak in memory usage. Due to this peak I often have to reduce the Threads parameter and therefore ...
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Objective value does not equal X * obj
AnsweredRecently I encountered that (in some of my models) the variable values seem to be incorrectly stored into my data. When I try the following int i, error;double total_obj_by_hand=0, total_obj_by_gur...
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Model infeasible after using GRBfixmodel
AnsweredAfter using the GRBfixmodel function my MILP is reported to be infeasible since the upper bound of some variables that are zero in the optimal solution is set to a (small) negative value instead of...
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Out of memory though memory is not exceeded
Awaiting user inputI am trying to solve a MILP using Bender's decomposition. Since there are many binary decision variables in the master, I need a lot of iterations. In the first iterations everything works just fin...
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Modelling squared euclidean distance in objective function (C-API)
AnsweredI want to implement the following objective function in the C-API: min (x²-1) + (y²-1) As far as I see it in the documentation I would need to reformulate the objective function to min x²-2x+1 + y²...
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ValueError using model.addMConstr since gurobipy 11.0.0
AnsweredSince updating to gurobipy I receive an ValueError when I try to use addMConstr if I include constraint names. Here is a minimal reproducible example: import gurobipy as gpfrom gurobipy import GRBi...
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using cmake -H. -Bbuild fails
AnsweredHi, I am trying to use CMake to use gurobi in C like described in https://support.gurobi.com/hc/en-us/articles/360039499751-How-do-I-use-CMake-to-build-Gurobi-C-C-projects-. However, when I try to ...
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Reduce memory usage of gurobipy Model
AnsweredHello, I am working with quite large linear models and finding myself with problems regarding memory usage. Building the model I observe a huge increase in memory consumption when I use model.addMV...