AMPL Modeling Language
https://groups.google.com/d/forum/ampl
A discussion and help group for AMPL, an algebraic modeling language for optimization problems of many kinds. AMPL lets people use common notation and familiar concepts to formulate models and examine solutions, while the computer manages communication with appropriate solvers.enpresolve: constraint SLC['s3'] cannot hold:
https://groups.google.com/d/msg/ampl/5VSSlTDL8FU/zA40D1FSBAAJ
I stucked up in this error....please see the attached data and mod files and help me to solve this error. Thankshttps://groups.google.com/d/topic/ampl/5VSSlTDL8FU
RSTue, 17 Oct 2017 08:37:44 UTCNested loop with changing parameters values - error
https://groups.google.com/d/msg/ampl/66CR1ZmukKI/nDQkpU4MBAAJ
Hello everyone. I am new to AMPL. I am trying to execute a loop in two layers where i am trying to change the initial values of my variables and the values of my parameters in each loop. However I get the error when I try to run I get the following message: "error at _cmdno 40 executing "let"https://groups.google.com/d/topic/ampl/66CR1ZmukKI
18...@novasbe.ptMon, 16 Oct 2017 11:14:48 UTCNEOS command syntax error - CPLEX
https://groups.google.com/d/msg/ampl/ueh1oZHa0gA/ExoKzqFvAAAJ
Dear AMPL users, I start to learn how to use NEOS for running model files with the CPLEX solver. However, I keep having syntax error for commands. Here is what my run file contains: *option solver cplex;option cplex_options 'integrality=1e-8 mipdisplay=2 mipinterval=200 timing 1 ';optionhttps://groups.google.com/d/topic/ampl/ueh1oZHa0gA
Fei XieFri, 13 Oct 2017 16:01:01 UTCHow to set multithreads parameters in AMPL for Gurobi?
https://groups.google.com/d/msg/ampl/gNR0HPVQppw/B75-KdVEAAAJ
Dear Sir/Madam, I have a very large ILP to solve and would like to use multiple threads inside AMPL mod so that once a thread finds a solution then the main program exists. But I could not find detailed instruction to build such a AMPL mod online. please helphttps://groups.google.com/d/topic/ampl/gNR0HPVQppw
davidFri, 13 Oct 2017 02:56:43 UTCLagrangian relaxation with subgradient method
https://groups.google.com/d/msg/ampl/ybnqWoJrWGE/tmfiOEXvAgAJ
Hello everyone I'm doing a lagrangean relaxation for a production planning problem but I do not know how to write the codes to optimize the penalty using the subgradient method. I have knowledge of the steps to follow for the iterations of this method thanks to this scheme (attached) but myhttps://groups.google.com/d/topic/ampl/ybnqWoJrWGE
Isadora HochfĂ¤rberThu, 12 Oct 2017 20:11:27 UTCProblem with ampl_lic_service / AMPL API for MATLAB
https://groups.google.com/d/msg/ampl/VAfJtyI-oyQ/cEs1bKIgAAAJ
Hi all, I have a problem with AMPL API for MATLAB. It seems that there is an issue with the closing procedure. If I run AMPL via MATLAB on one machine and afterwards on another one, it does not work anymore (the license manager prevents usage of AMPL). If I start AMPL directly, i.e. nothttps://groups.google.com/d/topic/ampl/VAfJtyI-oyQ
Martin GlanzerThu, 12 Oct 2017 15:53:22 UTChelp needed
https://groups.google.com/d/msg/ampl/dxBf3SPMDwE/le0uVc3EAgAJ
i am facing this error in solving command: ampl: reset; ampl: model 'C:\Users\Sameer\Desktop\ampl.mswin32.20161231\models\snd.mod'; ampl: data 'C:\Users\Sameer\Desktop\ampl.mswin32.20161231\models\snd.dat'; ampl: option solver cplex; ampl: solve; presolve: constraint SLC['s3'] cannot hold: body <=https://groups.google.com/d/topic/ampl/dxBf3SPMDwE
RSThu, 12 Oct 2017 07:13:13 UTCAMPL shuts itself during algorithm
https://groups.google.com/d/msg/ampl/peO2DQoLqq4/xxCaYkFaAgAJ
Hi there, I don't find an answer and don't quite understand the problem itself. I modelled an iterative ant colony algorithm (quite complicated to explain). One iteration looks like this: - solving an MIP 50 times with CPLEX (different input is given). This takes ~ 0.5 sec per solve -https://groups.google.com/d/topic/ampl/peO2DQoLqq4
TobiWed, 11 Oct 2017 14:45:12 UTCMINLP returns infeasible solution.
https://groups.google.com/d/msg/ampl/Leii8X-omc8/yWVFgVclBgAJ
I'm using the MINLP solver to solve a nonlinear mixed integer optimization problem of finding a good training subset for the SVM learner. Below I attached the model and command. The problem is that MINLP often returns infeasible solutions to the nonlinear constraint on the continuous variablehttps://groups.google.com/d/topic/ampl/Leii8X-omc8
Xuezhou ZhangTue, 10 Oct 2017 13:34:26 UTCMINLP returns infeasible solution
https://groups.google.com/d/msg/ampl/3BKqo1coWbc/94pKJPkdAgAJ
Hi all, I'm using the MINLP solver to solve a nonlinear mixed integer optimization problem of selecting training subset for SVM. The problem I have is that the MINLP solver often returns solutions with the continuous variable theta not satisfy the nonlinear constraint. This happens often when Ihttps://groups.google.com/d/topic/ampl/3BKqo1coWbc
Xuezhou ZhangTue, 10 Oct 2017 04:16:02 UTCVRP with latest arrival objective
https://groups.google.com/d/msg/ampl/JdHDtx0D6gU/3uxuikf9AQAJ
Hi all, I am working on a VRP that minimizes the latest arrival. Essentially given m vehicles I want to find the route that minimizes the latest time that a node is visited, instead of the normal minimize the total distance. If anyone could help me I would really appreciate it. I have a basehttps://groups.google.com/d/topic/ampl/JdHDtx0D6gU
Erin MullinMon, 09 Oct 2017 18:16:55 UTCparameters depending from variables.
https://groups.google.com/d/msg/ampl/fqktqHqiBA0/L67yP7fbAQAJ
Hello. I am writing to know if it is possible to create a parameter which value depends from the value of a variable. I'd like to have a parameter referred to a prduct j which value is 1 if the variable referred to product j is 1, if the variable is 2 the parameter value should be 10, if thehttps://groups.google.com/d/topic/ampl/fqktqHqiBA0
Andrea Di TarantoMon, 09 Oct 2017 08:01:52 UTCFw: RE: How to declare a binary variable by for-loop variable in AMPL?
https://groups.google.com/d/msg/ampl/z5Wjy2ru2So/UBQbvdHyAAAJ
Dear Sir/Madam, Thanks for your quick reply! I still have another problem: I need declaring a binary variable x in the AMPL mod file, which has following feature: for {i in 1..n-1 by 2} {x[i]=x[i];https://groups.google.com/d/topic/ampl/z5Wjy2ru2So
davidSat, 07 Oct 2017 00:58:28 UTCampl/gurobi: can't open /tmp/at16918.sol
https://groups.google.com/d/msg/ampl/oOsmxJj3mTY/O0RggK2WAAAJ
Hello everybody, I am using a 32GB of RAM, 8 cores 64-bit Linux computer. When I run the problem with a small data set using (ampl/gurobi) everything works fine and gurobi gives me an optimal solution. But when I increase the problem size I get: ampl: commands ilp.run; Presolve eliminateshttps://groups.google.com/d/topic/ampl/oOsmxJj3mTY
Hend Ben SaadThu, 05 Oct 2017 04:45:29 UTCSetting an integer constraint outside the variable declaration
https://groups.google.com/d/msg/ampl/v7uo7Y9oBZ8/oAoru1JSAgAJ
I want to selectively set and disable integer constraints on some variables in a model. Something like this: set index_values := {"A","B","C","D"}; set index_subset := {"B","D"}; var x{index_values}; subject to SomeIntegerConstraints{i in index_subset}: x[i] integer; # force x[i] to takehttps://groups.google.com/d/topic/ampl/v7uo7Y9oBZ8
Geoffrey BrentThu, 05 Oct 2017 02:49:26 UTC