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Questions tagged [xpress-optimizer]

32 questions
6
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2 answers

using Xpress failed

when I type using Xpress it show me two errors. One is LoadError: XPRESS cannot be loaded. Please run Pkg.build("Xpress") and another is Failed to precompile Xpress [9e70acf3-d6c9-5be6-b5bd-4e2c73e3e054] to…
Jiaming Xu
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1 answer

Trouble with incorporating Xpress solver in Julia

I'm trying to use Xpress solver in Julia-Jump. However, I have trouble to make Julia find the location of my Xpress installation. I'm using a Mac. I downloaded the Xpress, obtained license, put the license in the right folder, added these following…
user496181
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Variables in optimization problem using the python library Xpress

My optimization problem reads an excel file into a dataframe, and is to minimize the total value of all cells (16 x 27 cells). It is 16 vessels that have the opportunity of being retrofitted and reduce emissions by 5% if retrofitted. The…
Felix Dietrichson
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1 answer

How to use XPRESS as solver in Google OR Tools?

Google OR Tools says that it supports FICO XPRESS. Using Python, calling help(pywraplp.Solver.CreateSolver) I see that it supports - XPRESS_LINEAR_PROGRAMMING or XPRESS_LP - XPRESS_MIXED_INTEGER_PROGRAMMING or XPRESS or XPRESS_MIP I do…
jbuddy_13
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1
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1 answer

Invalid constraint using where in xpress optimizer

How can I use a nonlinear function like numpy.where in xpress solver in Python? Is it possible? If not, what other method to use?
Gheouany Saad
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1 answer

How to print results in Mosel

I am attempting to create a mosel model that takes data from an excel file and concerns energy demand for 20 regions. Each region has 3 possible alternatives corresponding to the kind of energy centrals we're considering in the model and a maximum…
Gabriele Errico
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Solving several problems concurrently with multithreaded application and XPRESS solver

I am trying to convert a single threaded application that uses Fico Xpress solver to have it solve several problems concurrently with OpenMP. The licensing method that I am using is limited to 1 process, so a multithreaded program should theorically…
wtf8_decode
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1 answer

Warm start in Pyomo + Xpress

I'm dealing with a big optimization problem. Pyomo is used as a wrapper, xpress is used as a solver. Every run I save the values of variables in order to load these values into variables before solving the problem again. So I want to implement a…
Vladimir
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1 answer

Invalid Constraint when using the addConstraint with the xpress library in python

When running this code import numpy as np import xpress as xp z = np.array([xp.var () for i in range (200)]).reshape (4,5,10) t = np.array([xp.var (vartype = xp.binary) for i in range (200)]).reshape (4,5,10) p =…
Fidel Chan Romero
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1 answer

Formulating MIP with FICO xpress using Pyomo

How do I solve an MIP model with FICO Xpress, via Pyomo? In addition, I want to set parameters of Xpress like miptol and miprelstop. How do I do that in Pyomo?
Tina
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1 answer

Why does my model ignore a linear constraint?

I have an Xpress IVE linear programming model whose objective is to maximise the profit from producing and selling energy for a fictitious company. One of the sources of energy is hydro. There is a reservoir with max capacity, so within the model we…
BobMarley
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1 answer

Dynamic number of indices in Xpress

I want to have a variable where depending on the use cases may have different number of indices. That is in some cases, the variable may be of the form V: array(set of string, set of string) of mpvar, while in some other cases, it may be V:…
Hung H
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1 answer

How to use Xpress NonLInear with Pyomo?

I wrote a dummy nonlinear example with Pyomo: import pyomo.environ as pyo model = pyo.ConcreteModel() model.N = pyo.RangeSet(0, 2) model.x = pyo.Var(model.N, within=pyo.NonNegativeReals, bounds=[5, 1000]) model.objective =…
fontanf
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how to code epsilon constraint model in Xpress

I want to used the ε-constrained method to solve a problem a posteriori and plot the set of Pareto optimal solutions and the Pareto front. I think I've managed to do this as my results look similar to what I achieved with the weighted sum method,…
marsh
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1 answer

Python Xpress get computation time and related statistics

Xpress has some built in logging, including computation time, total memory available and threads used. However, there's quite a bit extraneous information in these logging statements. Is there a method to get this sort of information? What I'm…
jbuddy_13
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