67 questions
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162
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How to linearize the product of two continuous variables?
I'm trying to solve a MILP problem in Matlab Optimization Toolbox. I'm encountering with problems with the product of two decision variable of my problem which are bounded.
0<= x <= 60
0 <= ...
0
votes
0
answers
53
views
Linearizability proof of a toy SET implementation over a filesystem
I'm currently studying concepts related to linearizability and I struggle with going from the linearization points of an implementation to the actual proof of linearizability.
As far as I have ...
- 1
-1
votes
1
answer
205
views
Minzinc does not return optimal solution
Main question
Context: I specified an ILP encoding like the following:
<some preceding constraints bounding all variables in the objective term>
constraint <objective term> >= c;
...
- 133
0
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0
answers
121
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How to linearize the term in objective function not the constraints
I have tried to linearize the term product of two continuous variables in the objective function by McCormick envelopes in GAMS. However, the model does not have the constraints for the product so ...
- 15
0
votes
1
answer
329
views
Pyomo linearization of min(0,x1-x2) in MILP
I have a constraint in a MILP formulated in pyomo.
Thats a general formulation of it:
def constraint(m, t):
return (m.y[t] <= max(0,m.x1[t] - m.x2[t]))
model.constraint_c = pyo.Constraint(model....
- 11
0
votes
0
answers
168
views
Linearization of a non linear contraint (min between two positive variables)
I have the following restriction: min(A, B), where A and B are always positive. It's very simple to linearize this using binaries, but I have a NLP problem and I don't know how to approach this.
I ...
0
votes
1
answer
215
views
How to convert the following if-else conditions to Linear integer programming constraints?
if x ≥ 100,
then x -100 + p(x) ≤ 0;
else p(x) ≤ 0
p(x) is a linear function. We can add x ≥ 0 if it could make it easy.
I tried to make a binary variable z, if x ≥ 100, then z＝1; else z＝0. Then we got ...
0
votes
1
answer
128
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multiplication of two continuous variables - How to code in CPLEX opl?
I have a constraint in which two continuous variables are being multiplied (price and time) and as a method for linearizing my problem I want to convert price to a discete variable and then doing ...
0
votes
2
answers
307
views
How to let two Python abstract classes implement each other's abstract methods?
Suppose you have abstract classes A1 and A2. Each of them has an abstract method and a concrete method.
from abc import ABC, abstractmethod
class A0(ABC):
pass
class A1(A0, ABC):
def foo(...
- 3,773
0
votes
0
answers
508
views
Linearize multiplication/division of two variables in Linear programming
I have a Linear programming problem I am trying to formulate. I need to define a variable which is the fraction of one particular variable divided by the sum of this variable over the entire set it is ...
- 1
1
vote
1
answer
83
views
Why is my Phobos not orbiting around my Mars? It keeps making a straight line
I don't get how to fix it. I commented out some bits because I can't seem to find the initial velocity of Phobos. Here's my code:
import math
import matplotlib.pyplot as plt
G = 6.6743*(10**-11)
...
1
vote
0
answers
96
views
How can I formulate these constraints for the optimization math programming (MIP)
I am struggling with some constraints that have ranged variables and several decision variables.
The constraints are
`if a[i] <= t <= a[i]+b[i], then M[t][i] == 1,
else if t < a[i] or t > ...
- 13
2
votes
1
answer
179
views
Linear constraints for nonlinear variable relationship
Assume a mathematical optimization problem with two positive continuous variables:
0 <= x <= 1
0 <= y <= 1000
I am seeking of an efficient way to express in form of linear constraints (...
- 95
1
vote
1
answer
291
views
Modelica/Dymola Run Linearized Model with Initial Values
I am new to Dymola and I want to run a linearized model with initial conditions.
I know how to Linearize it. I can get the StateSpace object in Command window or get the dslin.mat.
Now I want to run ...
- 11
1
vote
0
answers
343
views
Symbolic Small Quantity Approximation in MATLAB
I am trying to make a small angle approximation in MATLAB's symbolic toolbox. This is being used for the equations of motion in a spacecraft control simulation (and yes, I need to linearize, I can't ...
- 11