All Questions
19 questions
0
votes
0
answers
69
views
How to define this complex labor rule as a constraint in MIP?
Im trying to define a complex labor rule as constraints in a MIP, solved with CPLEX.
My key decision variable is a binary x(i,j) indicating if shift i is assigned to employee j.
The labor rule is as ...
2
votes
1
answer
246
views
How to set Gurobi to stop after the objective value reaches a certain threshold in Julia?
I am trying to run a minimization problem for an MIP using Gurobi in Julia. I would like it to stop after it has found a solution that is below a certain threshold that I have set. I have found ways ...
- 21
0
votes
1
answer
380
views
How to clone a cplex object in Java?
I am solving a problem in Java using the CPLEX library. I use a class "Model" to create a CPLEX object, and add to it variables, objective function and multiple constraints. This is the ...
0
votes
1
answer
288
views
Why does CPLEX set unrelated variables as 1?
I have been working on a combinatorial optimization problem which can be modeled as an integer linear programming. I implemented it as a c++ project in visual studio 2017 and CPLEX1271. Since there ...
- 361
0
votes
1
answer
52
views
How can I make a variation limits, do not exceed a specific value
Now I am facing a problem that making a variation does not exceed a specific value.
I will describe in details below.
using CP;
int a = 4;
int b = 3;
int c = 5;
range arange = 1..a;
range brange = ...
- 25
1
vote
1
answer
262
views
How to avoid scheduling conflicts for a timetable problem
I'm trying to create a schedule for shifts for each employee given employee shift availability. I have a tuple defined to include shift start time, shift end time, max people on shift. The input also ...
- 35
0
votes
1
answer
983
views
If condition in Cplex objective function
I am new to Cplex. I'm solving an integer programming problem, but I have a problem with objective function.
Problem is that I have some project, that have a due date D, and if project is tardy, than ...
- 1
1
vote
0
answers
160
views
How do I get the minimum positive value over a set of integer expressions?
I have a model with the following condition:
z[i] = min{t*x[i][t] | x[i][t] = 1},
x[i][t] - boolean,
z[i] - integer
Which means I am trying to find a minimum positive value over a set of integer ...
- 1,364
0
votes
2
answers
1k
views
If condition in Integer Programming
I am solving an integer programming problem with the condition
if a=0 then b=0 else b=1
where a is integer while b is binary
I looked on previous question similar to this but could not find ...
0
votes
1
answer
108
views
CPLEX not substituting equality correctly?
I am quite new to CPLEX and I am writing a very simple model that CPLEX does not want to satisfy. I know my model is "verbose" as I have variables that simply equal other variables, but it is my first ...
- 1,221
0
votes
1
answer
723
views
CPLEX using LP file format: indicator constraints with boolean operators
I am completely new to CPLEX and far from an expert in MIP but I am trying to solve a problem with this technology (CPLEX 12.4).
I ahve decided to create the MIP models in an .lp file and give it to ...
- 1,221
3
votes
2
answers
8k
views
How many decision variables can be solved for Mixed Integer Programming?
I have a Mixed Integer Programming problem(binary integer variables), how many variables can I solve, i.e, upper limit and what would be time taken?
The problem would have a utmost 5 constraints and ...
- 161
1
vote
1
answer
589
views
How to generate cuts and find an integer solution
I have an integer programming problem that looks for example like this, but with much more variables and constraints
It is equal to the 3SAT problem. There is no object function, so any integer ...
- 293
2
votes
1
answer
1k
views
How to change lp to mip when using CPLEX callable library
I've solved an lp using CPLEX callable library (in VS2010). The lp is the following:
Maximize
obj: x1 + 2 x2 + 3 x3
Subject To
c1: - x1 + x2 + x3 <= 20
c2: x1 - 3 x2 + x3 <= 30
...
- 65
2
votes
2
answers
738
views
MATLAB has crashed when using CPLEX API for linear programming
Hi I want to solve linear programming (LP) problem which has 25000 binary variables and almost 2555 equality constraints and 50 inequality constraints , so I used cplexbilp function which CPLEX API ...
- 322