Newest Questions
4,614 questions
1
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20
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HiGHS solver not returning binary results
I am using HiGHS with the ompr R package for modeling. I just had to re-install ompr and HiGHS. A model I made last week, with all binary variables, is now returning non-binary results for the ...
- 815
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17
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Is this a scientifically accurate way of describing what my heuristic does?
I am developing a heuristic approach for my thesis, I am in fact more of an imposter in the area and have some concerns regarding what I aim to show. I will first explain what my heuristic does: The ...
- 33
0
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31
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Property of the optimal solution of an optimization problem
$m \geq 2, n \geq 2 .[m]=\{1,2, \ldots, m\} \text { and }[n]=\{1,2, \ldots, n\}.$
Vectors $c$ $\in \mathbb{R}_{++}^{m}$(strictly positive), $w$ $\in \mathbb{R}_{++}^{n}$ and $\sum_{i \in[n]} w_{i}=1$....
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3
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43
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Proving the non-negativity of the optimal solution of a constrained quadratic programming
I have the following quadratic problem:
$\max$ $a^Tx+0.5x^TAx$
$s.t: 1^Tx=1$
in which $a=[a_1, a_2,\dots,a_n]$ is a non-negative vector, and $1^T=[1,1,\dots, 1]$. The Hessian matrix $A$ has ...
0
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36
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+50
How to show and prove the gapped C1-Property
This is a re-up. I have a scheduling problem which I solve with Column Generation (no Branch-n-Price). There I have the patients $i$, the doctors $j$ and the days $k$. While trying around, I noticed ...
- 39
-1
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1
answer
34
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Using CPLEX in the Julia environment of Google Colaboratory
I have a multi-stage mixed-integer stochastic global supply chain optimization problem formulation and want to solve its stage-wise problem instances using the CPLEX solver within the SDDiP algorithm ...
2
votes
1
answer
60
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Reference request - Multi-objective discrete optimization
I'm looking for references to do a review of research on solving discrete optimization problems with multiple objectives. Ideally a recent book / survey papers summarizing latest advances would be ...
- 29
-1
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21
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Correct literature category for therapist-patient assignment with fixed arrivals and no no-shows
I'm currently setting up a model, but I'm having a hard time categorizing the topic in the 'correct' area of scientific literature, as I think it can fall under several categories. Specifically, it is ...
- 29
1
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0
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87
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Is this recursive formula for the inventory lot problem correct?
I was discussing the following problem and its naive dp solution with a friend recently
and we had a disagreement whether the dp formula presented below solves or not the problem.
The friend insisted ...
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2
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answers
76
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Best/Easiest library for doing optimization in a computer graphics application
We have a graphics application (actually, it's a virtual reality app), where we need to solve a non-linear optimization problem at least once per rendering loop. So, we are looking for a library that ...
- 121
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44
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A set Counting Problem
Consider three positive integers $W, u (<W), v (<W)$ and all $u$-sized subsets of $[W]=\{1,2,...,W\}$. I have to make a collection $\mathcal{L}$ of $v$-sized subsets of $[W]$. with the following ...
-1
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0
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57
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Benders decomposition with binary variable in subproblem
I am currently trying to use benders decomposition solving an MILP problem. But there is a binary variable in my subproblem, which I cannot split to master problem. Is there any way to deal with? I ...
1
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0
answers
74
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CPLEX doesn't respect the LazyConstraintCallback I added
I am trying to imitate the following code to implement some lazy cut myself.
https://github.com/IBMDecisionOptimization/docplex-examples/blob/master/examples/mp/callbacks/cut_callback.py
Here is my ...
- 11
2
votes
1
answer
83
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Optimized Python package for Tabu Search?
I’ve been searching for a Python package that implements Tabu Search but haven’t found any that seem popular or actively maintained. Most libraries I’ve come across seem like individual efforts, with ...
- 51
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44
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Subtour elimination in the case of multiple visits
I have two type of nodes: $S$ for multiple visits and $C$ for a single visit. I'm trying to avoid the case of subtour. With the formula $(A)$, I could handle some cases but still can not avoid the ...
- 193