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.
Questions tagged [docplex]
316 questions
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Maximize revenue with deadline
Given three interval variables say
a = mdl.interval_var(name='a',start=(0,10),end=(0,10),size=5) #have revenue of 10
b = mdl.interval_var(name='b',start=(0,10),end=(0,10),size=5) #have revenue of 5
c =…
william007
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Docplex ! Interrupt the execution
I execute a program in cplex python (docplex), it has arrived at a gap 48% with 41 solutions. it's already been 2 days, I ask if I can interrupt it and have a result without restarting the execution with limit gap.
Nada.M
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CPU Time Limit does not work in docplex api in python
I have set up docplex api in python and I am trying to run an optimization models. Based on IBM documentation, a CPU time limit can be set for the problem using the following command:
mdl.solve(TimeLimit=60)
However, this attribute does not work…
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DOCPLEX Activate and deactivate constraints
I am trying to iterate through a MIP model with my own branching algorithm. So at each iterations, I am assigning all the binaries a value (0 or 1). Based on the results, I change how I assign the values. As an efficiency step, I have defined all…
Abilash
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DOcplexException: Expression xx cannot be used as divider of xxx
I am new to CPLEX and I was trying to find an example where the decision variable is in the denominator of the objective function but couldn't. My optimisation problem;
I have tried the following on Python3;
from docplex.mp.model import…
S.Perera
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Checking for feasibility and unsatisfied constraints in Docplex CP solutions
When I create an mp model in docplex I can check whether or not a solution is feasible and can show the unsatisfied constraints for infeasible solutions:
from docplex.cp.model import CpoModel
from docplex.mp.model import Model
mp_model =…
Finn
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How to obtain the total number of cuts in docplex?
I'm trying to obtain the total number of cuts from a solved docplex model, so basically the sum of the following output:
Implied bound cuts applied: 7
Flow cuts applied: 10
Mixed integer rounding cuts applied: 7
Zero-half cuts applied: 2
Lift…
Anonymous
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Docplex, large number of iterations ( ItCnt = 1.25e+08)
When running the cplex model "docplex(python)", I noticed that the CPLEX repeats the same gap value several times (more than 300 times). without any improvement and with a large number of nodes left to explore (even if the problem is not big enough,…
Nada.M
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Get the value of resource used
Given the code below (example from:https://www.ibm.com/docs/en/icos/20.1.0?topic=f-pulse)
from docplex.cp.model import CpoModel, INTERVAL_MAX
import docplex.cp.utils_visu as visu
mdl =…
william007
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How do I implement presence_of(x) => absence_of(y)
I'm trying to solve a scheduling problem in Python using docplex.cp.
In my problem I have a constraint that states that if a given optional interval variable is present, then some other optional interval variable must be absent.
I have tried…
Momafa
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docplex shift end in step_at_end method
I am solving a scheduling problem in python using docplex where I am assigning start/end to workorder intervals. I also have a cumul function for stock that the workorders produce/consume. I am using step_at_end method to add produced quantity to…
RMat
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docplex - set an interval_var's size as a function of another variable
In IBM's docplex optimization library, can you set an interval_var's size parameter as a function of another variable? Meaning, say for this example I wanted to make the task size dependent on the skill level of the worker. If the worker has a skill…
conv3d
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transfer CPLEX mathematical model from C++ to Python
I have programmed my mathematical model in C++ using CPLEX，now I want to transfer it to Python using docplex.mp.model
I met some problems in adding constraints. In C++，I am used to add constraints like this
for (j = NumD; j < NumDC; j++)
{
…
neal 123
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Single-source and multi-destination problem in CPLEX/Docplex?
Can we use the CPLEX/Docplex for single-source and multi-destination problem in a network? For example, routing a vehicle from a source to visit multiple destinations in a single trip minimizing the overall travel time.
bsha
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Examples in docplex to use the user cut callback method technology
Please can you provide an example of how this can used in a python notebook environment with docplex. I see examples with java on ATSP problem. The point is I do not know how to create these cuts upfront. Given a LP root node, I can generate the…
pudu39
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