Originally posted by: 88Simon88

Hello everybody,

I want to add some assumption to my model according to the below article, but it doesn't work for me

https://www.ibm.com/support/knowledgecenter/SSSA5P_12.8.0/ilog.odms.ide.help/OPL_Studio/opllang_quickref/topics/tlr_opl_assert.html

How can I fix it?

Best

Hi

you seem to mix OPL modeling and OPL scripting

assert should be  in the modeling part but you wrote that in a scripting block

regards

PS: https://www.linkedin.com/pulse/making-decision-optimization-simple-alex-fleischer/

Originally posted by: 88Simon88

Hi,

Thanks for your help, but how can I use "if-else" in the OPL modeling?

Best

Hi

int a=1;
execute
{
if (a==2) writeln(2);
else writeln("Not 2");
}

string res=(a==2)?"2":"Not 2";

execute
{
writeln(res);
}

gives

Not 2
Not 2

regards

Originally posted by: 88Simon88

Hi,

It still does not work :(

Let me explain the assumption one more time:

According to my data, I have to use an assumption in a conditional method. If the demand for all time periods is less than the "min_volume", the AAC in the data should be greater than the "min_volume". On the other hand, if the demand is not less than the "min_volume" for all time periods, the AAC should be greater than two times of the "min_volume".

I wrote the above execute for assert but it doesn't work for me. 

Best

Hi,

you mix scripting and modeling.

Let me give you an example

range r=1..2;

int a[i in r]=i;

assert sum(i in r) i<=10;

execute
{
var s=0;
for(var i in r) s+=a[i];
if (s>10) fail();
}

works fine

regards

Originally posted by: 88Simon88

Thanks Alex for the time you spent.

I understood what you mean. You said the assert is related to the OPL modeling and not OPL scripting, but how can I write an "if-else" statement in the OPL modeling? Because I have a condition for my assumptions?

Best

You may use the ternary operator in the modeling part

See

string res=(a==2)?"2":"Not 2";

I shared with you previously

regards

Originally posted by: 88Simon88

I even tried that and I couldn't do it :(

Hi,

again let me share a tiny example

range r=1..2;

int a[i in r]=i;

assert forall(i in r) as:a[i]<=3;

and

range r=1..2;

int a[i in r]=i;

assert forall(i in r) as:  if (i<=1) (a[i]<=1); else a[i]>=2;;

best regards

Originally posted by: 88Simon88

Thank you so much Alex