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.enHow to use the amplgsl solver and the smpswriter
https://groups.google.com/d/msg/ampl/XbW7xpX74RM/oz20cjHhAAAJ
Hello, Good afternoon. I just found the smpswriter can be used to solve the two-stage SP model, but I do not know how to used it. Did someone used it before and tell me the detail? Feihttps://groups.google.com/d/topic/ampl/XbW7xpX74RM
Sun FeiMon, 22 May 2017 19:10:35 UTCSwitching between models gives "error processing objective"
https://groups.google.com/d/msg/ampl/dHvufUjQO9g/zb94KlXaAwAJ
Hi, I am trying to automate a process that involves iteratively solving two different models. Roughly speaking, the process goes: 1. Solve the "Master LP" (MLP) 2. Use some of the decision variables of the MLP as parameters for the "attacker sub-problem" (ASP) 3. Solve the ASP 4. Use somehttps://groups.google.com/d/topic/ampl/dHvufUjQO9g
chris.man...@gmail.comMon, 22 May 2017 07:02:18 UTCNEED HELP - BENDERS DECOMPOSITION
https://groups.google.com/d/msg/ampl/gm8Bfyw76Zs/3AhwHElQAAAJ
I am trying to solve a problem using benders decomposition. I problem I have is that the solution in the first iteration is infeasible and I keep getting infeasible solutions. Could someone please help me out. Here is the code. # MEM Problem using Bender's Decomposition #MEM_BD.mod ##### SUBhttps://groups.google.com/d/topic/ampl/gm8Bfyw76Zs
Rakesh ReddySat, 20 May 2017 22:55:07 UTCIf-then constraint
https://groups.google.com/d/msg/ampl/4JoG1u6R3Sc/ZyIO1GSYCAAJ
Hi all, I have been trying to work on an if-then statement for my model but so far I cannot do it. Basically, what I want to do is the following: *IF *the presolve of *contraint1* is different than 0* THEN *do not execute *constraint2, constraint3... constraint10. *But *IF* it is equal to 0https://groups.google.com/d/topic/ampl/4JoG1u6R3Sc
Andres CastilloFri, 19 May 2017 23:00:14 UTCdisplay matrix
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I have three-dimensional matrix, Matrix[a,b,c]. Is it possible to display this matrix by specific dimensions, for instance 'b'? Something like: for{ b in 1..b_Length}{ display matrix[*,b,*]; }https://groups.google.com/d/topic/ampl/qEHZJqdgqpk
Mateusz NowakFri, 19 May 2017 09:59:19 UTCI’m running into a problem that I’m trying to resolve…wondering if someone in your shop has a suggestion.
https://groups.google.com/d/msg/ampl/hzER6iB4PW4/rkiwsGjVAgAJ
I’m running into a problem that I’m trying to resolve…wondering if someone in your shop has a suggestion. I’m doing a study on solving clique partitioning problems where I’m comparing two models (one linear and one quadratic, both in binary variables) and four solvers (cplex, gurobi, xpresshttps://groups.google.com/d/topic/ampl/hzER6iB4PW4
gary.koc...@ucdenver.eduThu, 18 May 2017 23:20:49 UTChelp plzzz
https://groups.google.com/d/msg/ampl/AUnS5theWjg/S8GpW8KyBAAJ
Hello ; here are the data and model files in the attachment. Its a simple linear program but the data is a bit large. Can anybody help me find the mistake, I need this as soon as possible, it's really urgent. thanks againhttps://groups.google.com/d/topic/ampl/AUnS5theWjg
ampl workThu, 18 May 2017 15:07:44 UTCSubscripted set in variable declaration
https://groups.google.com/d/msg/ampl/AkVqWpmapoY/SV62pYivBAAJ
Hi, I'm trying to solve such problem using AMPL: I have a set of Nodes and Edges that create a network. Each Edge has its own set of available wavelengths, called Lambdas (for sake of example, let's say it is 4), then each lambda can carry up to 10 Gbit/s (units are not that important here). Inhttps://groups.google.com/d/topic/ampl/AkVqWpmapoY
Mateusz NowakThu, 18 May 2017 14:08:38 UTCmatlab api
https://groups.google.com/d/msg/ampl/u0GUwoxgnxw/boEeFI-2AgAJ
Hi, I want to set “randseed” through matlab api setOption: see below.. So, how to set “randseed” through this api? ======================================================== >> ampl.setOption('randseed',3) Error using HandleException (line 15) No method 'setOption' with matching signature foundhttps://groups.google.com/d/topic/ampl/u0GUwoxgnxw
Zhicheng X ZhuThu, 18 May 2017 13:55:29 UTCData problem
https://groups.google.com/d/msg/ampl/EXlUM-FX9O4/UafWU5GDBAAJ
Hello everybody.I am working on a linear program on ampl and it seems like i have problems concerning the data. I don't really get what's wrong. Can anyone tell me what to do ? thanks < https://lh3.googleusercontent.com/-twrUN87NwMk/WRztpEeVH3I/AAAAAAAAAK4/n6JwIWnP4ZwJ7F8RaMu1jxAQF8u9fp7kQCLcB/s1https://groups.google.com/d/topic/ampl/EXlUM-FX9O4
ampl workThu, 18 May 2017 00:42:57 UTCQuestion equality
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Hello together, i want to solve the following equality: i dont need an objective function, because i only want to have a feasable solution. s.t. NB1 {i in 0..cF-1}: (n[i+1])*m*P[i+1] + l*P[i-1] = (l + n[i+1])*P[i] n[i] = Param, 0..3 l,m = Param P[i] = variable In the case i=0 i havehttps://groups.google.com/d/topic/ampl/fh7g9Xyzj8A
pitau.scorpionWed, 17 May 2017 12:42:26 UTCCplex Run time
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Hi I am solving a large MIP problem in cplex and it is taking too much time even i have around 8000 binary variables.. Presolve has eliminated 128899 rows and 23571 columns... Presolve has improved bounds 917 times... Aggregator has done 488 substitutions... Tried aggregator 4 times. MIPhttps://groups.google.com/d/topic/ampl/ew-UZj3QWQw
mahii...@gmail.comWed, 17 May 2017 12:41:01 UTCNeed help
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Hello, Below is the practice code for the scenario tree model. I can not run out the result. Would you help me find out where has the problem. Thank you! model file: param T; # number of periods set investments; # different investment options set periods:=1..T; param initwealth; # initialhttps://groups.google.com/d/topic/ampl/Y8fCxtfKI4g
Sun FeiWed, 17 May 2017 00:53:50 UTCerror in 1 subscript
https://groups.google.com/d/msg/ampl/okbYJKOS9Pc/sTot_5lCAQAJ
Hi all, How can I solve this problem? I want to define param avg in 2 dimension!! How can I get this? What is the problem with the code below? Also I want the number of 4 avg equal in number of VS set because I use of this code in 2 dimension! Is it correct??? WBR set VS:= {1..4}; param ahttps://groups.google.com/d/topic/ampl/okbYJKOS9Pc
sahebe...@gmail.comTue, 16 May 2017 19:37:00 UTCOptimizing many times with many datasets. Reading and writing from/to file.
https://groups.google.com/d/msg/ampl/KLLNtZyU5n8/VvYouWE7AQAJ
Dear Members, I have 10 thousand datasets as a (.txt) file organized as follows (according to AMPL Book - only numbers without colons etc; # I have added now): number1 number2 ... number6 #first dataset number7 number8 ... number12 #second dataset and so on. I would like AMPL to 'readhttps://groups.google.com/d/topic/ampl/KLLNtZyU5n8
czarek...@gmail.comTue, 16 May 2017 17:24:41 UTC