Questions tagged [pulp]
Questions relevant to the PuLP modelling framework in Python
76
questions
3
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2
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820
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How do I turn off preprocessing in pulp?
There is an inbuilt preprocessing in CBC solver which affects the optimality of my solution. I get the optimal output by turning this off at the command prompt. How do I turn this off using pulp?
- 119
0
votes
0
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35
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Binary variable taking floating values in multi trip VRP with TW
I am trying to solve a multi trip VRP with time windows in pulp (minimizing total distance travelled). The code is providing optimal results for multi trip VRP without time window constraints (however ...
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1
answer
94
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How to write conditional constraints and sum the result in Linear Programming in Python?
I want to use the sum of a series of linear expressions as objective and constraints. These linear expressions are chosen to be included or not based on some conditions. I can achieve it in Excel ...
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0
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58
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Need help for the python scheduling code
I'm working on a Python application using PuLP for optimization, and I'm having trouble ensuring that only one material is produced on a given day.
The constraint prob += pulp.lpSum(production_flag[m][...
0
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1
answer
108
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Ensure complete cycle in binary succession matrix LP [PuLP]
I have a set of orders N, for which i have to determine an optimal sequence. I wrap this decision within a binary matrix x[i][j], meaning whether i is succeeded by j.
For example
[[0 1 0 0]
[0 0 1 0]
[...
CommunityBot
- 1
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votes
1
answer
78
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PULP: Optimization Assignment of Bicycle production per month
Q1. If bicycles of types A and H are produced, then bicycles of type C can be produced with 20% shorter working hours, while selling profit of bicycles type H can be 20% higher.
Q2: If bicycles of ...
- 5,894
0
votes
2
answers
117
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Extracting a sequence as a decision variable from a matrix (PuLP)
I am solving a sequencing problem x[i][j], i.e. a binary matrix indicating that product i is followed by ...
CommunityBot
- 1
1
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1
answer
134
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Unique values constraint in Pulp
Can we directly model following constraint in pulp
x != y
as following:
...
- 2,865
0
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1
answer
74
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Issue with Mathematical Model Using PuLP Library
I'm working on a pulp python code for the MS-RCPSP (multi-skilled resource-constrained project scheduling problem), I need to update the code to address a specific scenario: when an activity requires ...
- 3,513
0
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0
answers
33
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Shipment Allocation using Pulp
I am trying to create a model where each shipment must be allocated to a route to minimize the freight cost. I am a complete newbie at LP Optimization.
Explanation of dataset:
Every destination (D1,...
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0
votes
1
answer
92
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Pulp Optimization with Decision Variable as Boundary
I am currently working on a linear programming problem using the Pulp library in Python. The problem involves optimizing the capacity of a battery, which is represented as a decision variable in my ...
- 1,895
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0
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194
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Detect presolve status in pulp model
I am running a model using pulp CBC and have few constraints in the model that may make the model infeasible if wrong input is given to the model.
I can see while my model runs that in case of ...
- 1,895
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1
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259
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PuLP is ignoring constraints, and setting everything to 0 for minimization problem
I have a multi-objective optimization problem I am trying to solve with competing objectives. I am trying to model a network of industrial businesses which can share wastewater rather than sending it ...
- 484
1
vote
1
answer
301
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Creating a decision variable that is the sum of other variables in PuLP
I'm trying to represent the following problem with PuLP:
A car factory needs to maximize profit with an X amount of car models. Each car model has an individual profit and a manufacturing limit, and ...
CommunityBot
- 1
3
votes
1
answer
369
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Warm starting a LP problem with PuLP and Gurobi
I have a set of many similar linear programs (LP). All these LPs have the same objective function, and almost all constraints are the same. The only difference is for one linear constraint $f(x)=a_{i}$...
- 1,703
1
vote
2
answers
591
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PuLp is ignoring all of the constraints given to it
I am trying to solve a portfolio optimization problem using PuLP where given a dictionary of stock tickers and their returns for the day, returns a set of weights for each stock such that portfolio ...
- 2,865
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1
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182
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applying a piecewise linearized equation in pulp
The background is I'm building a toy rent vs. buy mortgage calculator. I am an experienced software engineer but my math skills are 20 years behind me and I admit to being very lost.
I've been using ...
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3
votes
2
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291
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Binary Integer Programming Problem - Enforce Zeros on Certain Groups
I'm working on a binary integer programming problem using pulp. I have a vector X = [x_1, x_2, x_3, . . . , x_n]. I have enforced a number of simple constraints. I ...
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3
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1
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225
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Assignment Problem - Students and teachers
I ran across this problem at work and I'm sure that we can optimize it with OR.
I have $n(T) = 4$ teachers and $n(S) = 7$ students that should have a weekly individual class.
If a student $s$ has a ...
- 484
2
votes
1
answer
125
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How to linearize the multiplication by a binary decision variable?
I am currently optimizing a hydrogen production chain.
I am optimizing the production regime, and the size of the required wind, solar and the electrolyser.
For every hour of the year, the production ...
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1
vote
2
answers
259
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Efficient ways to do pairwise/multiplicative variables in integer linear programming on PuLP / Python
I'm trying to formulate an LP that is in essence a variant of the sudoku problem, and I've repurposed the code from https://coin-or.github.io/pulp/CaseStudies/a_sudoku_problem.html.
The differences ...
- 3,513
0
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3
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243
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Using PULP to model machines in a factory
Complete revision:
I have all 4 machines that can run in positive and negative directions which results in 2 outputs:
$ P_1 = \begin{cases}
-390 \le P_1 \le -300 & \text{for neg mode}\\
0 &...
- 484
1
vote
3
answers
99
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PuLP ensure first and last choice
I have an assignment problem where I have $N$ locations and $M$ dates for each location, and the goal is to choose $K$ location-date pairs that maximize revenue. There are a number of constraints, for ...
- 33.6k
2
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3
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Any Idea why PuLP is ignoring binary variables?
When I solve the following code, the binaries for the lines_selection variable is not respected by PuLP. Can anyone please point me out to the reason why this could ...
- 3,513
-2
votes
1
answer
75
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Mixed Integer programming - Problem modelling coincidence restriction in scheduling match problem
I am trying to model and solve a problem for maximize audience of matches that must be scheduled in different slots (I am using python PulP library). Below I explain the problem and the model process ...
- 119
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2
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Pulp problem gets the right objective value but fails to find the minimal solution
I converted an excel solver problem to Pulp. However, while the pulp program calculates the objective function value correctly, it doesn't arrive at the right answer. I can't figure out what is wrong ...
- 39
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1
answer
519
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Understanding reduced costs and dual values
I have a headache regarding calculating the reduced costs of a linear program. I am using Pulp for modelling and CBC for solving.
What I do is, I model a linear programming problem based on a rhs ...
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3
votes
1
answer
442
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Multi period inventory / reordering MILP in PULP
I'm trying to optimize reorder quantities for $n$ products over $m$ periods in PuLP. The total reorder quantity should fill a container. I've never worked with multiple periods before, and I can't get ...
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1
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512
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How to save log file from pulp , log including algorithms used by the solver?
How to save log file from pulp , log including algorithms used by the solver ?
while this is printed in the python IDE console, looking to save it as a txt file .
- 1,726
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0
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305
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Problem of optimal solution generated with Pulp
I'm trying to use Pulp to solve VRP problem. Here is the model:
...
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-1
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1
answer
174
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Modeling a problem with python pulp transportation problem
I am trying to solve the following problem.
How to build a deterministic optimization model for the following fc
we have $x_1,x_2,...,x_365$ are the order shipped from an FC to a customer for 365 days
...
3
votes
2
answers
314
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Simple Integer Optimization Problem: docplex CP model works but equivalent PuLP+CBC model is infeasible?
I have an integer optimization problem with one constraint per decision variable and no objective function. It can be coded and solved using docplex, however I am ...
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2
votes
1
answer
106
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Split variables into groups, each constrained to hold a specific number of variables, while optimizing group sums towards specific values
I have a number of variables each assigned an integer value. I need to split these variables in three groups with a predefined number of variables going into each group while optimizing towards ...
- 40.1k
3
votes
2
answers
190
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Find all pivots that the simplex algorithm visited, i.e., the intermediate solutions, using Python
For my research, I am interested in finding the trajectory outlined by the pivots along the way of optimizing an LP problem, but I only know how to use Python PuLP to obtain the optimal solution. Is ...
- 1,895
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votes
2
answers
145
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Inventory Continuity Equation
I have to minimize the inventory remaining at end of the period(28 days). Each item would perish after a fixed number of days and we can order items only on certain weekdays(M,T,S,S). Demand is ...
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6
votes
1
answer
4k
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How to call HiGHS solver from python PuLP MIP?
I have a large MIP built with PuLP in python, and want to utilize the HiGHS Solver. However, PuLP does not have the option to use HiGHS as a solver. One option I am aware of would be to use PuLP to ...
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1
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317
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PULP : Constraint violation - multiple of expected value
I am developing a linear programming model in PULP that sends material from Origin Facilities to Transfer and Final Treatment Facilities. The objective function is based on summing the transport and ...
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0
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172
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Profit Optimization in Python with Difficult Constraints to Maximize Net Revenue
I am currently trying to work on this problem that determines the best constraints on how to place these 'bids'- please see the second column in the screenshot:
The ask at hand is to uncover a model ...
- 1,895
4
votes
1
answer
743
views
Subtour elimination implementation (DFJ) using Python (PULP). While loop never exits
The simple test problem I'm trying to implement is
\begin{align}
\min &\quad c_{ij}x_{ij} \\
\text{s.t} &\quad \\
&\quad \sum_{j\in N}x_{ij} = 1, \quad i\in N\\
&\quad \sum_{i\...
- 2,673
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1
answer
2k
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How to formulate cumulative sum of LpVariable in Pulp Python
I have a Multiple product LP optimization problem in which the product(B1,B2,D) will be received in variable quantity with respect to date column.
The Optimizer should LP variable Output as Assy Out ...
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-1
votes
1
answer
223
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I'm trying to solve an OR problem written using pulp framework , with gurobi, in Linux , but I'm not able to solve it
I'm trying to solve an OR problem written using pulp framework , with gurobi, in Linux , but I'm not able to solve it . In windows,I use this command to use gurobi ,
...
- 3,469
2
votes
2
answers
474
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Find the list with the fewest elements whose cumulative sum reaches threshold
I have a question with which I am stuck and would be very grateful for help:
I have multiple lists of non-negative numerical values (all of the same length)
I want to find the list with the lowest <...
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2
votes
1
answer
2k
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Defining Objective Function in PuLP
I have a binary variable $X_{ijk}$ which I have defined as the following :
...
- 1,572
6
votes
1
answer
955
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Python "Coffee Shop Scheduling Problem" - Scheduling Lunches/Breaks
I'm working on an employee scheduling program in python. Having never done this before, I've been researching different libraries that can be used to accomplish the task.
Unfortunately, none of the ...
- 1,895
3
votes
2
answers
704
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Designing a multi-commodity network flow optimizer
I'm trying to solve multi commodity multi source network flow optimization problem using Python-PuLP. Here is how my problem looks like:
The numbers on the arcs represent the order of priority a ...
- 40.1k
4
votes
2
answers
788
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Python Pulp - LpMinimize Not Returning Expected Output - Scheduling Problem
I'm working on my first pulp model and something isn't going quite right. It looks like it's close, but for some reason it is not respecting one of my constraints...
It's a scheduling problem and I am ...
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1
vote
1
answer
2k
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Pulp Python - How to define a constraint with different indexes of variables
I am new to modeling LP with Pulp in Python and I need some help with defining a constraint with multiple variables with different indexes. Please see below.
The constraint is defined on A, B, C ...
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2
votes
1
answer
711
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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 ...
- 1,895
3
votes
1
answer
4k
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Complicated constraint with logical operators in PuLP
I have an optimization problem that I am trying to solve with PuLP.
All the variables are Booleans.
The variables that are "selected" will be true, all others false.
Objective function is ...
- 33.6k
5
votes
1
answer
151
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How to transfer an optimization problem written with GUROBI (in python) in a grammar that can be readily solved with another solver?
Trying to use an opensource optimization tool in python (having used only gurobi for years) I see that the whole code (representing the optimization problem in pythonic language) must be written ...
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