Search found 166 matches

by Fred
1 week ago
Forum: Announcements
Topic: issues running GAMS with MacOS Catalina
Replies: 4
Views: 246

Re: issues running GAMS with MacOS Catalina

Hi Alireza, You could install GAMS 29 beta which has been released earlier this week and should just work with Catalina: https://www.gams.com/29/ For older versions, please install the Mac version of GAMS and follow one of the workarounds described in the previous posts of this thread. I hope this h...
by Fred
1 week ago
Forum: Syntax
Topic: Ignore input data for elements not defined
Replies: 1
Views: 110

Re: Ignore input data for elements not defined

Hi, With a GDX data layer, you have lots of flexibility when it comes to loading the data into GAMS. Besides the filtered read you get with $load, you can for example turn on domain checking when items are loaded with $loadDC or merge data into an already defined symbol with $loadM, etc. For more de...
by Fred
2 weeks ago
Forum: Syntax
Topic: Beginner Question: Using csv as an input
Replies: 8
Views: 1449

Re: Beginner Question: Using csv as an input

Hi, I ran the following and it works: $onecho > shockC.csv ,sp1,sp2 2019,51.59000962,221.2765056 2020,297.1442391,198.4488019 2021,30.89360312,106.7259835 $offecho SETS yr year /2019*2039/ scn scenario /sp1,sp2/ Table shockC(yr,scn) 'shock path' $ondelim $include shockC.csv $offdelim ; display shock...
by Fred
3 weeks ago
Forum: Announcements
Topic: issues running GAMS with MacOS Catalina
Replies: 4
Views: 246

Re: issues running GAMS with MacOS Catalina

Dear GAMS Users, In the meantime, we found a much simpler workaround for the issue with macOS Catalina (10.15). You can open the GAMS Terminal app and enter the following: cd /Applications/GAMS28.2/ && xattr -rd com.apple.quarantine sysdir/ Note that you might have to adjust the path (/Applications/...
by Fred
1 month ago
Forum: Modeling
Topic: Increasing ‘reslim’ but weaker result in a mip solver
Replies: 5
Views: 159

Re: Increasing ‘reslim’ but weaker result in a mip solver

One potential explanation could be that you suffer from non-deterministic behavior when cplex hits the time limit. When you use time limits, the solving process becomes non-deterministic close to the end of the time limit. Eventually, Cplex does "something smart" close to the end with reslim=360 whi...
by Fred
1 month ago
Forum: Modeling
Topic: Increasing ‘reslim’ but weaker result in a mip solver
Replies: 5
Views: 159

Re: Increasing ‘reslim’ but weaker result in a mip solver

Hi,

What about the log files and files required for reproduction?

Fred
by Fred
1 month ago
Forum: Modeling
Topic: Increasing ‘reslim’ but weaker result in a mip solver
Replies: 5
Views: 159

Re: Increasing ‘reslim’ but weaker result in a mip solver

Hi, Assuming that you solve the exact same problem on the exact same hardware with the exact same software and that there are no other computationally expensive jobs running simultaneously, increasing reslim should not lead to a worse solution. You don't say whether you minimze or maximize but from ...
by Fred
1 month ago
Forum: Modeling
Topic: GAMS/convert solver
Replies: 2
Views: 515

Re: GAMS/convert solver

Hi, MPS is a file format for linear problems: https://en.wikipedia.org/wiki/MPS_(format) If you look into the resulting mps file, you should see hints like * Cannot handle NLP [...] * Cannot handle nonlinear equations, nonlinear part ignored. * Cannot handle nonlinear equations, nonlinear part ignor...
by Fred
1 month ago
Forum: Syntax
Topic: Dynamic set allocation with binary variable
Replies: 9
Views: 970

Re: Dynamic set allocation with binary variable

Hi, you are absolutely right. I edited my post accordingly.

Fred