forum.polymake.org

Not sure if this is intended behaviour, but this works:
while this does not:
And random access seems to be the only way to access the content of $simplexFace.

The faces of a Hasse diagram are of type Set<Int>, which can be determined by calling so random access is not actually foreseen in their interface (not quite sure, why the first version works, probably some perlish voodoo...).
There are various ways to access its elements on the perl side:

• You can convert it, for example to a perl array or an Array<Int> via

  Code: Select all

  @sface = @{$simplexFace}; $sface_arr = new Array<Int>($simplexFace);
• You can iterate over it using entire:

  Code: Select all

  for($it = entire($simplexFace);$it; $it++) { print $$it,"\n";};

Hope that helps!

Thanks, I will convert it to an array then!

... not quite sure, why the first version works, probably some perlish voodoo...

No vodoo at all. The Set behaves as any other container allowing to visit elements in ascending order. These three ways of iterating over set elements are equivalent, the first one having the smallest runtime overhead:

for my $elem (@$simplexFace) { ... }

for my $index (0..$#$simplexFace) { my $elem=$simplexFace->[$index]; ... }

for (my $iter=entire($simplexFace); $iter; ++$iter) { my $elem=$$iter; ... }

If you need true random access to its elements, then you indeed have to copy it into a plain perl array:

my @face=@$simplexFace;
my $elem=$face[$index];
...