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I have this optimization problem: In this problem, C_{i,k} is a matrix of binary values (i.e., 0 or 1) and w_i is a vector of integers, p_f is a probability, and \epsilon is a constant. I understand ...
Amedeo's user avatar
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1 answer
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Some time ago I am writing an OR related article for publication. In the article a MILP model is show for a certain Optimization problem using MiniZinc. I resolve 10 instances optimally out of 10 ...
afdez's user avatar
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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 ...
cmp's user avatar
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I am trying to build a linear constraint that follows this logic if either x1 = 1 or x2 =1 then y1 = 1 but if x1 = 0 and x2 = 0 then y1 = 0 if both x1 = 1 and x2= 1 then y1 = 1
Johnvir Pangli's user avatar
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I have written the following code: How to interpret auxiliary constraints and sub tour elimination constraints in the following formulation?
sudarsan vs's user avatar
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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). ...
ctyler9's user avatar
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I wonder if anyone is able to suggest some packages to solve a non-linear optimisation problem which can provide integer variables for an optimum solution? The problem is to minimise a function with ...
andrew_overflow's user avatar
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I've created a MILP model to test using the Docplex library in python but I get this error message : CPLEX Error 1016: Community Edition. Problem size limits exceeded. Purchase at http://ibm.biz/...
TheGuardian's user avatar
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I am new to mystic and working on an optimization problem.My mystic code looks like this: def find_loss(e,lmd,q,k): edge_pmf=find_final_dist(e,lmd,q) l_e=sum(edge_pmf[k+1:]) return ...
Divyayan Dey's user avatar
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using python mip I have found that unlike gurobi to initialize a feasible model one should supply it to the model and not per variable. But I can't find an example or explanation of what format is ...
borgr's user avatar
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I am solving an MINLP using Pyomo, which takes a vector of integer inputs(the link capacities of a graph) and returns the packet loss in the network.What the edge_enum dictionary does is, it ...
Divyayan Dey's user avatar
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I am not familiar with linear programming. My expertise is in statistics, econometrics. So I might have written the code with some errors. But I have searched the sources as much as I can. In the ...
Gizem KAYA's user avatar
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I want to solve an integer programming model with cplex python. I have this model: a and h are matrixes with 0s and 1s. p is a set of numbers. here is a part of my cplex code for this model: p=[i for ...
Sana.Nz's user avatar
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I am uncertain whether it is possible to formulate the following problem in a linear fashion or whether i should attempt to optimize it non-linearly. I wish to find the optimal combination of a ...
Ingmar's user avatar
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1 answer
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when I run the GEKKO optimization, I got a 'FileNotFoundError', please let me know how to handle it. Is there any problem in my code? Y is Binary Integer Decision Variable. #initialize gekko model = ...
choi's user avatar
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how can i create decision variable of type xp.sos(fico xpress solver) from a list like this `i have 2 lists K and D with these set of elements as seen below.K is a list of trips and J is a list of ...
kawawamarc's user avatar
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I have the following SCIP solver log time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons |cols |rows | 0.0s| 1 | 0 | 4 | - | 6k| 0 | 0 | 6 | 200 | 6 | 200 |...
Morpheus's user avatar
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I was initially trying to implement a branch and price algorithm and I was mostly successful in implementing it. I implemented a pricer plugin and everything seems to work. But I want to strengthen ...
Morpheus's user avatar
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I am using the MIP optimization library to solve a problem, but I can't correctly declare the objective function. I wrote the code before using Gurobi to solve and I am just trying to translate the ...
the_dankest's user avatar
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I followed the example to branch using make_branch() in the control(branch) callback of the MIP. But I noticed that the solving processes differ surprisingly under different settings of the variable ...
Icarus's user avatar
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545 views

I am a beginner in Python. I'm using the mip package to optimize a standalone battery given hourly power price in a year. I need the program to pick 5 lowest price hours to charge the battery and 4 ...
Foxtail Fern's user avatar
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1 answer
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I'm trying to solve a MINLP with binary variables in Julia. I have a user-specific objective function which is non-linear and I have nonlinear and linear constraints. I tried to solve the problem ...
schMath1234's user avatar
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I am very new to this field. I am working on MILP type of problem, and I am using Python with Pyomo. Pyomo is very easy to use when you are having Single Objective Model. but in my case. it is ...
Nadeem Tabbaa's user avatar
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Which is more computationally efficient for a Mixed-Integer Problem Formulation: a. State the upper and lower bounds of the variables when declaring the variable b. Declare the variables with the ...
Bruno's user avatar
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4 votes
1 answer
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I have a few questions about how APOPT solves MINLPs. What nonlinear programming method APOPT uses (interior point, trust region, etc.)? How does APOPT deal with mixed integers (B&B, outer ...
Titus Quah's user avatar
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1 answer
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Now, I tried to add EQ7: a new constraint that make every start_pour[k][j] differ from others start_pour[k][j] that equal to site_process_time[c] to a runnable model. It showed a relaxed solution that ...
Natdanai I.'s user avatar
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442 views

I'm trying to solve the following problem using Google or-tools minimize f = x1 + x2 with the constraints x1 = 0 or 100 <= x1 <= 2000 x2 = 0 or 100 <= x2 <= 2000 x1 + 4 * x2 >= 650 ...
RasmusN's user avatar
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278 views

I want to implement a cut in a MILP, which will be added, if we encounter a MIP-feasible point. The cut shall be implemented by a cut-generation problem. I want to bound the linear cut-expression(the ...
Tobias Triesch's user avatar
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1 answer
301 views

Now I am trying to get a solution within a specific time-limit in my code. Actually, my problem(scheduling) is NP-hard. It spends lots of time to get a solution or out of memory. So, I set a time-...
sangho park's user avatar
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0 votes
1 answer
347 views

I am currently implementing my own heuristic to solve MILP problems in gurobi python interface. All my variables are continuous in the beginning and at some point of time the solution becomes ...
Morpheus's user avatar
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0 votes
1 answer
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I need some way to cap the sum of integer variables to be 1 at max in a python cvxpy optimization task constraint. What i do not want is to force the sum of the variables to be 1, I just need a ...
Vlad de Elstyr's user avatar
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1 answer
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I have a problem that I want to solve but I cant figure out how to model it Before asking here I made research and find things that will help but I couldnt wrap my head around it. Example of problem I ...
R. Carlson's user avatar
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313 views

I need some help modelling the following logic as a mixed integer linear programming constraints for a vehicle routing problem. The Variables involved are the following: Xij, SDVlmj, and MDVhkbj ...
gravityman123's user avatar
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2 votes
1 answer
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I'm using DOCPLEX to build up a Mixed Integer Linear Programming (MILP) problem which is then solved via CPLEX on Python. However, upon trying to solve the MILP problem using IF-THEN constraints, I ...
Muhammad Ali's user avatar
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1 answer
643 views

I'm solving a LP / MILP problem using ILOG CPLEX. int n = ...; range time =1..n; dvar float+ c[time] in 0..0.3; dvar float+ d[time] in 0..0.3; dvar float+ x[time]; int beta[time]=...; float pc[time]...
MiguelL's user avatar
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5 votes
1 answer
300 views

I am working on a project where I need to breakdown an integer value according to an array of percentage values. My end array must contain integer value and the sum of the array must be equal to the ...
Michael's user avatar
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247 views

I am trying to solve an optimization problem where different data sets are used as input. For most of the sets my programm utilizing the PuLP libary with the coin-or CBC solver works just fine. But ...
the_man_in_black's user avatar
  • 473
2 votes
1 answer
98 views

I'm trying to solve an optimization problem with CPLEX. //Variables int n = ...; range time =1..n; //n definido em data dvar float+ c[time] in 0..0.9; dvar float+ d[time] in 0..0.9; dvar float+ x[...
MiguelL's user avatar
  • 81
1 vote
2 answers
5k views

I am tried to solve a MILP problem using python pulp and The solution is infeasible. So, I want to find where infeasibility is coming and want to relax it or remove it to find feasible solution. it is ...
K N Reddy's user avatar
  • 13
1 vote
1 answer
295 views

I have a matlab script for diet linear programming problem. I am trying to compare results of linearprog or(intlinprog) with results of cplexlp(or cplexmilp) functions provided by toolbox CPLEX for ...
Omar Ayman's user avatar
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0 answers
195 views

I am trying to formulate a problem that will spit out an optimal schedule for my tasks to be completed. To keep the information confidential, I will refer to my tasks as papers that need to be written....
Dom's user avatar
  • 55
0 votes
1 answer
55 views

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 = ...
sangho park's user avatar
  • 25
0 votes
1 answer
256 views

Now I am trying to make an Iteration code by 'using CP' in cplex. The problem is raised when I use CP to get a solution about 'q1' convex. What should I do, What I need to change my code below. main ...
sangho park's user avatar
  • 25
0 votes
0 answers
86 views

I have a finite sequence of random positive integer numbers a1,…,aM and I am looking for an approximation algorithm (not exact) that finds sequence of z1,z2,z3,z4,z5,z6 (zigzag) that starts with z1=...
Iraj Shokouhi Bahar's user avatar
  • 13
0 votes
1 answer
38 views

Now I am facing with a problem about 'changing value of dvar B as dvar A changes when dvar B depends on A.' There is a code that I write, simply. int a = 3; int e = 4; int t = 6; int h = 2; range ...
sangho park's user avatar
  • 25
0 votes
1 answer
226 views

Just curious if libpynumero_ASL.dll is available for windows or it is only installable through linux/ios OS using pynumero libraries in conda?
grandtour's user avatar
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0 votes
1 answer
723 views

Now, I am facing with an error. 'Decision variables of type dvar float not supported by this algorithm.' Here is the code that I made. I will write it simply. Firstly, I got in trouble with error ...
sangho park's user avatar
  • 25
1 vote
2 answers
721 views

There are Two arrays A1[a][c], A2[b][c] Now I am trying to multiply each corresponding elements of these two arrays. int a = 3; int b = 4; int c = 5; range aRange = 1..a; range bRange = 1..b; range ...
sangho park's user avatar
  • 25
0 votes
0 answers
38 views

I'm solving a binary integer linear program (BILP). To generate the optimization expression, I take the dot product of vector of decision variables with the vector of each decision's value. The two ...
user36800's user avatar
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0 votes
1 answer
397 views

when I try to run the following script, error message:The expression contains a variable that is not part of the model. appr <- c(0.15, 0.11, 0.10, 0.13, 0.18, 0.20, 0.18, 0.11, 0.07, 0.06, 0.07, ...
Crubal Chenxi Li's user avatar
  • 313

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