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.enDoubt about the break to stop a FOR
https://groups.google.com/d/msg/ampl/DfSXF8obM8Q/jJiMSuyomSwJ
Hello, i have just noticed that in my algorithm i have a FOR inside a FOR and i have in the inner for a break inside a condition if...i thougt the break would stop only the corresponding FOR but it's stopping all the FOR . Is there a way to avoid this? for{ a in A }{ for{b in B}{https://groups.google.com/d/topic/ampl/DfSXF8obM8Q
Emanuel LagomarsinoMon, 30 Mar 2015 23:42:37 UTCMaximum amount of memory accessible on Unix sever
https://groups.google.com/d/msg/ampl/tt87ZivYRVI/3jzU2tbQ2yUJ
What is the maximum amount of memory that 64-bit AMPL can access on a unix sever? Is there any command that allocates memory? Thanks. Best, Lorenzohttps://groups.google.com/d/topic/ampl/tt87ZivYRVI
Lorenzo MagnolfiMon, 30 Mar 2015 18:36:26 UTC**Putting loops in Constraints
https://groups.google.com/d/msg/ampl/FeC67cxouzg/ky3RZHoN1lkJ
How to put this as a constraint?? for(i in regnodes){ for(j in regnodes){ if(i==j) continue; for(h in clusterheads){ if(y[h]==0) continue; if(x[i,h]*x[j,h]) v[i, j]=1; } } } I have tried using: subhttps://groups.google.com/d/topic/ampl/FeC67cxouzg
KrishnaMon, 30 Mar 2015 16:14:18 UTCProblem in writing a piecewise linear function.
https://groups.google.com/d/msg/ampl/i6g6Jb8vJtk/JvOEDiXbESAJ
Hello, I have a problem with writing a piecewise linear problem in AMPL. The problem is as follows: The objective function is minimize exp: sum{t in ti}p[t]*z[t]; both 'p' and 'z' are variables In the constraints I have defined 'z' and 'p' as z[t]=sum{a in ap}x[a]*I[t,a];https://groups.google.com/d/topic/ampl/i6g6Jb8vJtk
Krishnendranath MitraMon, 30 Mar 2015 04:44:30 UTCUsing AMPL api to fill Parameters??
https://groups.google.com/d/msg/ampl/m0mWu1KWijE/mKYotaQ1zH8J
How can i fill in the parameter value of a paramater in mod file using the AMPL api in Java?? My parameter is an N*N cost Matrix named c How can I set its value programatically into mod file? It is defined in mod file as: set nodes; param c{nodes,nodes} and in my program i have a matrix ohttps://groups.google.com/d/topic/ampl/m0mWu1KWijE
KrishnaSun, 29 Mar 2015 13:59:24 UTCAbout .unbdd
https://groups.google.com/d/msg/ampl/vP7Vl7NAhpg/IOcYIRv5_H8J
Hello Everyone, hope everything is going well. Consider the following tiny LP for illustration: var x>=0; var y>=0; minimize OF: -2*x-y; subject to c: x+y>=6; The feasible region is clearly unbounded and the extreme directions are (0,1) and (1,0). When solving with CPLEX I get the expechttps://groups.google.com/d/topic/ampl/vP7Vl7NAhpg
LNSat, 28 Mar 2015 20:59:15 UTCAMPL cannot be executed under musl
https://groups.google.com/d/msg/ampl/F6kRtff4qVE/QgzxcdGWUw4J
People using Alpine Linux, Void Linux, Morpheus Linux, etc. aren't able to run AMPL. We currently have to install less secure and more resource-hungry libcs (http://www.etalabs.net/compare_libcs.html) just to be able to get the AMPL binary to run, which isn't either an easy or elegant approach.https://groups.google.com/d/topic/ampl/F6kRtff4qVE
marc...@gmail.comSat, 28 Mar 2015 20:57:14 UTCAMPL does not run under musl libc systems
https://groups.google.com/d/msg/ampl/ZtkbPw1_aL0/XzkwivrpvNAJ
People using Alpine Linux, Void Linux, Morpheus Linux, etc can't run AMPL. They have to go through hard fiddling in order to get a less secure and more memory-hungry libc into their systems, using convoluted methods, just for AMPL. (http://www.etalabs.net/compare_libcs.html) I think a quick soluhttps://groups.google.com/d/topic/ampl/ZtkbPw1_aL0
marc...@gmail.comSat, 28 Mar 2015 17:21:40 UTCDefining a 2 dimensional variable slice by slice (e.g. row by row)
https://groups.google.com/d/msg/ampl/IwwiANWQBms/Dp4W_DpdPl8J
Hi, How can I define a 2 dimensional variable one row(or column) at a time? For example: set I := 1..2; set J := 1..6; var Y{i in I, j in J}; var Y{i in I: i=1, j in J} = X[j]; var Y{i in I: i=2, j in J} = 3X[j]; The above code does not work because Y is already defined (and probably becahttps://groups.google.com/d/topic/ampl/IwwiANWQBms
Alex FakosSat, 28 Mar 2015 17:12:56 UTCampl table
https://groups.google.com/d/msg/ampl/l0rJPwB2gI4/_qeFQd4L7zMJ
I am learning the AMPL code and have this basic question. In the TAB file below, the data of interest is really from second line down, what does the first line really mean? ampl.tab 3 2 FOOD cost f_min f_max BEEF 3.19 0 100 CHK 2.59 0 100 FISH 2.29 0 100 HAM 2.89 0 100 MCH 1.89 0 100 MThttps://groups.google.com/d/topic/ampl/l0rJPwB2gI4
Cuong P NguyenSat, 28 Mar 2015 03:37:25 UTCAMPL bug with sets?
https://groups.google.com/d/msg/ampl/piXOII12xhM/wnqMkBKoAYoJ
Hi, working on an AMPL script in which I am building up a graph G. For technical reasons the nodes of G are represented by relatively long(?) strings, around 120 characters long. The script has 2 nested loops and it runs for long time (takes some millions of iterations). The script, after rhttps://groups.google.com/d/topic/ampl/piXOII12xhM
Tamas VinkoThu, 26 Mar 2015 15:21:26 UTCpresolve and fix
https://groups.google.com/d/msg/ampl/kSEzwqrJwsg/OU_yDCjHAi8J
I am wondering if it is possible to somehow fix those variables which AMPL's presolve eliminates. It is possible to list these presolved variables, but how can they can be referenced? I tried fix{i in 1.._nvars: _var[j].status ='pre' } _varname[j] := _var[j]; but it does not work.https://groups.google.com/d/topic/ampl/kSEzwqrJwsg
Tamas VinkoWed, 25 Mar 2015 19:57:50 UTCmultiplication of linear forms not allowed
https://groups.google.com/d/msg/ampl/RLP1tlfwlWc/Xd62LDshIMUJ
Hello, I get this this error «multiplication of linear forms not allowed" with this constraint. Const {k in K,l in L, j in J,i in I }:F[k,l,i,j]<=F[k,l,i,j]*x[i,j]; F[k,l,i,j] is a positive variable of my problem x[i,j] is binary variable How could i change the formulationhttps://groups.google.com/d/topic/ampl/RLP1tlfwlWc
skylineTue, 24 Mar 2015 14:01:06 UTCAMPL and Dynamic generation of files
https://groups.google.com/d/msg/ampl/z0vkA3KPWx0/qLEYSUPJzDEJ
Hello, i have a doubt about generation of output files. Can I change a string name on AMPL, therefore allowing me to generate a different files in a FOR? Thankshttps://groups.google.com/d/topic/ampl/z0vkA3KPWx0
Emanuel LagomarsinoTue, 24 Mar 2015 12:47:14 UTCAMPL & Excel
https://groups.google.com/d/msg/ampl/dhUyeRRAsQQ/wJcrp5ow52oJ
Hi there. I want to know if I can export the results of AMPL to an Excel sheet. If it's possible, I want to know how I export it. Thank you very much Jose Cruchaga -- Saludos cordiales, José Miguel Cruchaga Campos Estudiante Ingeniería Civil Industrial Ayudante Dirección de Desarrollo Currhttps://groups.google.com/d/topic/ampl/dhUyeRRAsQQ
José Miguel Cruchaga CamposMon, 23 Mar 2015 21:18:29 UTC