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Questions tagged [docplex]

docplex (a.k.a. IBM® Decision Optimization CPLEX® Modeling for Python) is a Python modeling API that provides modules for mathematical programming via CPLEX and constraint programming via CP Optimizer.

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ILP problem using docplex CP Optimizer (Nothing to read from local solver process)

I solve my ILP problem using docplex IBM package for Python under CP Optimizer Model. It's working correctly, and I get the target result; however, when I call the Model.solve() many times. i.e., more than 10000 cycles, in the beginning, everything…
labed AbdelJalil
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My cplex script does not work on python with no error

I have been using Cplex and docplex (on python) on my PC for a long time and it was working fine. But lately when I run my script it starts the engine but it sticks at the beginning for a very long time (24 hours maybe) and then it terminates the…
Sana.Nz
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Converting docplex expression into string

How can I store the text version of a constraint defined as a docplex.mp.linear.LinearExpr variable into a Python string variable?
Omar Shehab
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Docplex: Building expression to get a value from an array

I have an array defined as follows A = [ [10,20], [20,10] ] Now I want to get the entry at a position (i, j). The thing is, j is a CpoFunctionCall object (where i will be an Int), so is not able to be indexed. Is it possible to have the operation…
Stackd
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Understanding DoCPLEX Multi Objective

I am working on Pure LP problem with around 3 Million Constraints and I am currently using objective function with different weights. But to improve run time I am hoping to explore DoCPLEX multi- objective import "ObjectiveSense". Before…
Kartik Kaushik
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DOcplexException: Expecting linear constraint, got: docplex.mp.LogicalOrExpr

I want to write a conditional constraint using docplex. The constraint is: if: y[(i, j,k)] == 1 or y[(j, i,k)] == 1 then: g[i,j,k]==1 I implemented the code in docplex in this way: mdl.add(mdl.if_then(mdl.logical_or(y[(i, j,k)] == 1 ,y[(j,…
Sana.Nz
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DoCPLEX Solving LP Problem Partially at a time

I am working on Linear Programming Problem with 800K Constraints and the problem takes 20 mins to solve but if I solve the problem for half horizon it just takes 1 min. Is there a way in DoCPLEX where I can solve for partial horizon and then use the…
Kartik Kaushik
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MIP Formulation Slow Performance

I am working on a model which is MIP. The model solves very quickly generally, but if I am trying to add IF- THEN constraint to the model the solve time exponentially increases to a point where its not able to get a feasible solution within 2000s. …
Kartik Kaushik
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How to implement a new constraint based on two other constraints on CPLEX?

I am very new to Cplex. I have these two constraints (R is the set of numbers in range 20) : model.add_constraints((model.sum(x[i, j] for j in R2 ) == 2 for i in R),"C1" ) model.add_constraints((x[i, n1-4] ==x[i, n1-2] for i in R…
Ashkan Rezaee
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How to asynchronously abort a solve in docplex?

I have 2 simultaneous solves running using docplex and I want to stop one of the solve as soon as the other one finishes. Is there an way to end one solve?
Kartik Kaushik
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Obtaining different solutions on solving a cplex model many times

I have an MIP model written with docplex and a solution pool written with cplex. My model has billions of solutions in reality. I need to solve this model several times (10 for example) with a certain populate number (10,000 for example) but I need…
Sana.Nz
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DoCPLEX: Kill Solve if one of 2 solves are complete

I am working on DoCplex problem in which I have 2 models. I am using ThreadPoolExecutor() to run the solves parallel. But is it possible to kill one of the solve once one of them is complete? I am using following code: def work(slvr): …
Kartik Kaushik
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Implementing Soft rules on CPLEX

I have a model that I need to add a new constriant to it but I want this rule to be implemented "only" if it is possible. Is there a way to implement this with cplex or docplex ?
Sana.Nz
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DoCplex MILP problem: Running Benders & Branch and Bound Parallel

I am working on MILP model (In DoCplex) and solver reaches the solution faster with Benders Method sometime and sometimes using Branch & Bound. Is there an easy way to run both solve methods parallel without changing variable names (cloning the…
Kartik Kaushik
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Python: Is there a faster way to filter on dataframe in a for loop

I have a for loop over a tuple in python which is index for one dataframe. All the values under the index are then summed over. Example: t3 = time() for row in list_of_index: a=[] if row[-1]!='end': a=df1.loc[row[:7]].to_numpy() …
Kartik Kaushik
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