Search found 295 matches
- 2 years ago
- Forum: Modeling
- Topic: Connecting binary variables
- Replies: 1
- Views: 1608
Re: Connecting binary variables
Hi, I don't understand your question completely but some things look fishy to me. You say yR(r) is a binary variable to choose one number out of 95. So this looks like you want to write binary expansion for integer variables. But you don't have a constraint saying only one yR(r) can be 1 and rest sh...
- 2 years ago
- Forum: GAMS-FAQ
- Topic: Utilizing multiple CPUs
- Replies: 0
- Views: 25737
Utilizing multiple CPUs
In the following, we will give an overview of the different ways to increase solver performance, mainly by considering hardware upgrading. Note that not all solvers have all capabilities and that the feature naming may differ, therefore, we explain a capability by taking a particular solver, as an e...
- 2 years ago
- Forum: GAMS-FAQ
- Topic: Can I use Dropbox with GAMS ?
- Replies: 0
- Views: 11546
Can I use Dropbox with GAMS ?
Using GAMS with cloud storage services (e.g., dropbox, onedrive, google drive) requires some caution and especially it is not recommended to place a GAMS working directory in such a synchronized cloud storage folder. A user can run into issues when a cloud storage service such as Dropbox has locked ...
- 2 years ago
- Forum: Modeling
- Topic: Iterating twice through the same set
- Replies: 3
- Views: 2023
Re: Iterating twice through the same set
I only provided the part that needs to be corrected. Of course you need the full equation constraint(k,i,ii)$(ord(i)<>ord(ii)).. r(k,i)) * x(k,i) =g= r(k,ii) )*x(k,i) ; I don't know what you are trying to solve, but this constraint itself does not make sense to me. there is x(k, i) on both sides of ...
- 2 years ago
- Forum: Modeling
- Topic: Iterating twice through the same set
- Replies: 3
- Views: 2023
Re: Iterating twice through the same set
You are missing "alias" https://www.gams.com/latest/docs/UG_SetDefinition.html#UG_SetDefinition_TheAliasStatementMultipleNamesForASet All you need to do is create an alias for set i. (say ii) alias(i, ii); now you can define your constraint constraint(k, i, ii) (ord(i) <> ord(ii)).. Hope t...
- 2 years ago
- Forum: Syntax
- Topic: unknown dollar control option
- Replies: 5
- Views: 3226
Re: unknown dollar control option
https://www.gams.com/38/docs/RN_cmex226 ... ch=$ifthen
$ifthen was introduced in 22.6. So you cannot use it. I am not sure what you can do and I can't test nor point you to documentation of such an old version.
- Atharv
$ifthen was introduced in 22.6. So you cannot use it. I am not sure what you can do and I can't test nor point you to documentation of such an old version.
- Atharv
- 2 years ago
- Forum: Syntax
- Topic: unknown dollar control option
- Replies: 5
- Views: 3226
Re: unknown dollar control option
I think it is also important to know which version of GAMS you are using.
- Atharv
- Atharv
- 2 years ago
- Forum: Syntax
- Topic: unknown dollar control option
- Replies: 5
- Views: 3226
Re: unknown dollar control option
Please show how you are using it (i.e., copy the line where you get this error from as it is). There is clearly some error in your syntax.
One possible reason is you have an unnecessary space $ ifthen instead of $ifthen
- Atharv
One possible reason is you have an unnecessary space $ ifthen instead of $ifthen
- Atharv
- 2 years ago
- Forum: Syntax
- Topic: How to lower relative and absolute gap?
- Replies: 3
- Views: 2757
Re: How to lower relative and absolute gap?
That's a vague question. It is also a completely different question. Unfortunately, there is no answer without looking at your model. In fact, your model could actually be very difficult and lowering gap is not in your hands. If you need further help, provide your entire code (may be in a separate t...
- 2 years ago
- Forum: Syntax
- Topic: How to lower relative and absolute gap?
- Replies: 3
- Views: 2757
Re: How to lower relative and absolute gap?
optcr and optca are tolerances that tell the solver when to stop. This has nothing to do with the absolute gap that solver achieves. You can set the tolerance however low you want, if the solver does not reach it, you will get bad results. The answer lies in reformulating your problem and doing othe...