random 'matrix error' inconsistent across GAMS installations
Posted: Mon Sep 20, 2021 10:11 pm
Hello,
Lately I have noticed a strange error on disparate projects (maybe 1 of every 100 runs, but random). The error is a 'Matrix error - bounds on discrete variables have to be integer'. Two things make this error strange: (1) my bounds are integer. I know this because they are set in an iterative loop from a previous GAMS solve using an integer variable solution (i.e. newVariable.fx=myVariable.l). I have even tried applying a round operation to this hand-off. (2) We have 3 servers running GAMS 35.1, when I try it on different servers with the same GAMS codebase, it works on all but 1. It isn't the server though, as this same thing has happened on a different server with a different model.
Further, I have noticed something as small as changing a single (completely unrelated) input parameter from 11.99 to 12 can cause this behavior. I have attached a picture of the issue below. My first thought was precision with the integer variable( i.e. eprhs), but again, I tried the round functionality and no dice. Please advise as this is causing trouble for our commercial customers.
Zack
Lately I have noticed a strange error on disparate projects (maybe 1 of every 100 runs, but random). The error is a 'Matrix error - bounds on discrete variables have to be integer'. Two things make this error strange: (1) my bounds are integer. I know this because they are set in an iterative loop from a previous GAMS solve using an integer variable solution (i.e. newVariable.fx=myVariable.l). I have even tried applying a round operation to this hand-off. (2) We have 3 servers running GAMS 35.1, when I try it on different servers with the same GAMS codebase, it works on all but 1. It isn't the server though, as this same thing has happened on a different server with a different model.
Further, I have noticed something as small as changing a single (completely unrelated) input parameter from 11.99 to 12 can cause this behavior. I have attached a picture of the issue below. My first thought was precision with the integer variable( i.e. eprhs), but again, I tried the round functionality and no dice. Please advise as this is causing trouble for our commercial customers.
Zack