Questions tagged [pulp]
Questions relevant to the PuLP modelling framework in Python
63
questions
2
votes
1
answer
306
views
Representing Date Variables in Pulp
I am working on an optimisation problem that involves minimising shipping demurrage. I am struggling to model how to represent the difference, (x-y) between dates where the ship is ready to be loaded ...
- 327
2
votes
1
answer
515
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Pulp Python: How to formulate a time-based variable for shipping demurrage
I am working on a shipping optimisation problem that aims to minimise demurrage charges as a result of low/insufficient inventory.
I have daily vessel requirement (sales) data in the format ...
- 327
1
vote
2
answers
1k
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Pulp: slack variable to identify & measure extent infeasible in supply problem
I am currently modelling a supply problem that attempts to optimise a rail schedule which moves products from a production plant, to a warehouse to satisfy sales.
The model is working fine (thanks in ...
- 327
3
votes
0
answers
97
views
Constraint equivalence in PuLP
I'm working on an optimization problem in PuLP and I have to enforce a daily minimum of shifts and a daily maximum of assigned shifts. I have the following constraints to ensure each day has a minimum ...
- 101
3
votes
1
answer
765
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How to set these constraints in a linear optimization problem (PuLP)?
I am trying to implement an employee (nurse) scheduling problem and seek some advice on how to implement a specific constraint.The problem is as follows: There is a set of employees and days (both ...
- 101
2
votes
1
answer
615
views
How to enforce this specific constraint in PuLP?
I am trying to implement an employee (nurse) scheduling problem and seek some advice on how to implement a specific constraint.The problem is as follows: There is a set of employees and days (both ...
- 101
13
votes
2
answers
603
views
"Out of the box" Mixed Integer Programming Heuristics
I currently have a complex Mixed Integer Program (a sort of vehicle routing problem variant, with multiple vehicle types and without assigned pickup -> delivery routes, among other complications) ...
- 131
4
votes
1
answer
780
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PuLP Transport Problem - How to add outcomes of decision variables together
I am working on a rail scheduling problem that moves product from a production plant to a storage facility to satisfy demand. I am new to PuLP so finding this difficult to understand why this isn't ...
- 327
6
votes
1
answer
569
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Advanced Heuristics for MIP vehicle routing problem in PuLP
I am currently trying to speed up an MIP. An approach I was considering was to implement a cut callback heuristic with PuLP (one which rounds relaxed integer variables greater than .9 to 1). ...
- 63
7
votes
0
answers
147
views
Why does PuLP call copy for addition and how can I avoid it?
Using a for loop to append terms to an expression seems to be much faster than summing a group of terms all at once. Constructing the expression using a for loop uses __iadd__, which does not include ...
- 261
11
votes
1
answer
1k
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Change coefficient in PuLP
Once a model is implemented in PuLP, how do you change a coefficient (e.g., $a_{ij}$, $b_i$ or $c_j$) of a program of the from $\min\{c^{\top}x: Ax=b, x\geq0\}$?
Specifically:
How to update ...
- 1,345
8
votes
1
answer
1k
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Read an LP/MPS file in the PuLP
I was trying to read a MPS file by using the PuLP package in the Python, but I can't find any related documents on it. Does ...
- 8,382
10
votes
1
answer
13k
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How do I access the value of a variable in PuLP?
In Python's PuLP package, how can I get the value of a decision variable?
For example, if I declare a variable—
...
- 13.1k