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.enLoop in a loop - Pool Solution
https://groups.google.com/d/msg/ampl/HkMwU1ZkvQM/2YA3V8x5uJsJ
Hi to all! I'm new in this forum and have a tricky problem with the pool solution. I have a “for-loop” and in this loop I solve a MIP. The run-file looks roughly like this: for { solve problem; for {i in 1 .. Current.npool} { solution ("kbpool" & i & ".sol"); displayhttps://groups.google.com/d/topic/ampl/HkMwU1ZkvQM
Marc MaiwaldSun, 03 May 2015 09:41:06 UTCRE: [AMPL 10361] Quadratic Integer Programm with Quadratic, Non-Convex Constraints, or: how to construct Pyramids?
https://groups.google.com/d/msg/ampl/P8KHPB5w89Y/CNkW_G1RBwgJ
For the simple problem you describe, I would favor a simpler model: param dim integer in {2,3}; param nBricks integer > 0; param maxL integer > 0; var Use {1..maxL} binary; maximize LayersUsed: sum {i in 1..maxL} Use[i]; subject to BricksAvailable: sum {i in 1..maxL} (2*ihttps://groups.google.com/d/topic/ampl/P8KHPB5w89Y
AMPL OptimizationFri, 01 May 2015 17:26:38 UTCCannot fix variables
https://groups.google.com/d/msg/ampl/kSAjbJhKKXI/Hg7Kn9Czf5IJ
Dear All, I'm trying to solve a problem iteratively in a decomposition fashion. However, I can't fix variable values in between. This is a parallel machine scheduling problem: first allocate jobs to machines, and then do sequencing. Here is the frame work. Solve the whole problem to chttps://groups.google.com/d/topic/ampl/kSAjbJhKKXI
arr...@gmail.comFri, 01 May 2015 16:56:19 UTCWhat is the meaning of ItCnt ( CPLEX ) ?
https://groups.google.com/d/msg/ampl/kFZLrrhcYVw/jqctBTjawSsJ
Hello, What is the meaning of the ItCnt and ItInf kolumns in the output from the CPLEX solver when solving IP problems? Best regards, Gustav. Skickat från Windows E-posthttps://groups.google.com/d/topic/ampl/kFZLrrhcYVw
Gus JarnFri, 01 May 2015 12:39:03 UTCNeed help with .mps file
https://groups.google.com/d/msg/ampl/HgLmVe3P7og/V9p425FRtxgJ
Hi, I used solverstudio to solve the problem. The file is attached. Here is my code: #this is the shelter location model #our objective is minmize the uncovered population #set set DEMANDNODES; set POTENTIALLOCATION; param Distance {DEMANDNODES,POTENTIALLOCATION}; #potential location wihttps://groups.google.com/d/topic/ampl/HgLmVe3P7og
Shiyang FanThu, 30 Apr 2015 16:54:36 UTCAbout output text file
https://groups.google.com/d/msg/ampl/Zndj3oKXCwA/9VJ51VPLXCkJ
I set var AllocationCarrier{0..50,0..10} AllocationCarrier is a result i want How do i only output the AllocationCarrier result to a file The file contents as follows : 0 1 2 3 4 5 6 .. 10 0 3 0 0 0 0 0 0 .. 1 2 2 5 3 5 4 4 5 1 6 5 . . . . . . 50 How shhttps://groups.google.com/d/topic/ampl/Zndj3oKXCwA
趙輕鬆Thu, 30 Apr 2015 13:35:03 UTCHow to treat missing data in AMPL
https://groups.google.com/d/msg/ampl/1s1X-UNSCg4/ah5TX5-slFQJ
To Whom It May Concern, My objective function is trying to minimize the sum of a set of covariance values. As a result, I have a decision variable indexed in two dimensions. However, the covariance matrix is relatively sparse, and so includes a lot of "." values. When I try to solve the problemhttps://groups.google.com/d/topic/ampl/1s1X-UNSCg4
jacob....@gmail.comWed, 29 Apr 2015 22:14:55 UTCAMPL
https://groups.google.com/d/msg/ampl/xfoXDuVmQQw/dOMEZoojlRAJ
Dear AMPL Team, I Need to work on AMPL for my Project. My Problem is Ft. Loudoun and Watts Bar are two large hydroelectric dams, the former upstream of the latter. The level of Watts Bar Lake must be kept within limits for recreational purposes, and the problem is to plan releases from Fhttps://groups.google.com/d/topic/ampl/xfoXDuVmQQw
Shanmugaraj VskTue, 28 Apr 2015 23:12:19 UTCNeed help with mps file
https://groups.google.com/d/msg/ampl/dLgbvMEZU98/QDbOmbeotLUJ
I want to write a .lp file to check the moedl. I know ampl cannot directly create .lp file. So I want to write a .mps file at first. There is my code. # Solve the problem option solver gurobi; solve; option auxfiles rc; write mshelter; It didn't create any file. What should I write in cohttps://groups.google.com/d/topic/ampl/dLgbvMEZU98
fate...@gmail.comTue, 28 Apr 2015 21:13:21 UTCEigenvalues as objective function?
https://groups.google.com/d/msg/ampl/Wlwbgxfoc0U/_ejmWVg-P6EJ
Dear Google-Group, I want to build an objective function in AMPL based on the Eigenvalues of a matrix within my *.mod file for solving a DoE problem. Has anyone experience in calculating Eigenvalues in AMPL for e.g. 10x10 - 100x100 matrices? The matrix is often singular and I expect some Eigenvhttps://groups.google.com/d/topic/ampl/Wlwbgxfoc0U
matthias....@gmail.comMon, 27 Apr 2015 16:46:46 UTCConstraint causes infeasibility
https://groups.google.com/d/msg/ampl/YrP7qZbyA3o/lhYryV8y73cJ
Hello! I'm doing an optimization which purpose is to investigate whether it is possible to deduct products from other company's storage facilities. For this I've defined: set T ordered; #The set of time periods set I; #The set of storage facilities set J; #Thehttps://groups.google.com/d/topic/ampl/YrP7qZbyA3o
CenderzeSun, 26 Apr 2015 10:09:28 UTCBinary variable definition
https://groups.google.com/d/msg/ampl/yzpBkbzS7uY/5xzTkGBcKf8J
Hi, i would define a binary variable x_j depending by the value of binary variable y_ij such that: x_j = 1 iff at least one of y_ij = 1. how can i define that? thank you!https://groups.google.com/d/topic/ampl/yzpBkbzS7uY
MariettoosSat, 25 Apr 2015 14:07:05 UTCFinding certain suboptimal solutions in a MIP
https://groups.google.com/d/msg/ampl/Om44C3e79cM/2o-svfL494YJ
Through some of these answers I learned about the "solution pool" concept that creates .sol files with suboptimal solutions that are part of a MIP branch and bound algorithm. I have it working relatively well, but I'm getting solution that are still very close to the optimal. I am using: poolcaphttps://groups.google.com/d/topic/ampl/Om44C3e79cM
carv...@berkeley.eduFri, 24 Apr 2015 16:32:29 UTC