Re: Adding if/then/else statement to GMPL

[Domingo Alvarez Duarte]

Hello Heinrich !

That example was a silly one only to do a minimal check that the add if/then/else was working (properly?).

My implementation doesn't seem to need much code and allow a bit better expressiveness to GMPL.

Another example from examples/pentomino.mod:

Before:

====

for {i in 1..m}

{ for {j in 1..n}

{ for {0..0: (i,j) in R}

{ for {(c,ii,jj) in S: (i-ii,j-jj) in D[c] and x[c,ii,jj]}

printf " %s", substr(c,1,1);

}

for {0..0: (i,j) not in R}

printf " .";

}

printf "\n";

}

====

After:

====

for {i in M}

{ for {j in N}

{ if (i,j) in R then

{ for {(c,ii,jj) in S: (i-ii,j-jj) in D[c] and x[c,ii,jj]}

printf " %s", substr(c,1,1);

}

else

printf " .";

}

printf "\n";

}

====

Cheers !

On 24/8/20 16:59, Heinrich Schuchardt wrote:

> On 24.08.20 16:33, Domingo Alvarez Duarte wrote:
> > Hello Meketon !
> >
> > Could you share your view of how it would be expressed (an ideal model
> > sample) ?
> >
> > If you want to talk about it, maybe I'll be interested in implement it !
> >
> > Can you share a collection of models data to be used as base for the
> > test/implementation ?
> >       
> Dear Domingo,
>
> I do not yet understand what was you weren't able to express with the
> current syntax.
>
> Instead of
>
> if length(p) == 3 then display "true 3"; else display "false 3";
> if length(p) == 5 then display "true 5"; else display "false 5";
>
> you can write:
>
> param p,symbolic := "dad";
> display if length(p) == 3 then "true 3" else "false 3";
> display if length(p) == 5 then "true 5" else "false 5";
> solve;
> end;
>
> Best regards
>
> Heinrich
>