[PPL-devel] a Bug, a Beg and a Binding

[Enea Zaffanella]

Axel Simon wrote:
> I don't think I do anything that could invalidate the iterator. Here is 
> the Haskell code (and an explanation between the lines in C):
> 
>>   cs <- PPL.polyhedronMinimizedConstraints p
> 
> cs=ppl_Polyhedron_minimized_constraints(p)

[...]

> time. I would like to debug it but it is kind of hard since all 
> interesting functions are in-line. It could be something with my binding 
> to Haskell, but I just thought I ask if somebody has experienced the 
> same problem with the C interface before going down that route.

One simple test that you can do is to explicitly call function 
ppl_Polyhedron_OK() on polyhedron `p' just after retrieving its 
minimized constraint system. This will check if the (coded) polyhedron 
invariants are all valid (see documentation). I do not expect this call 
to fail, but if it does, then it will be an indication that the problem 
is caused somewhere else before this program point.

Of course, the above test is already done implicitly (and it is thus 
redundant) if you have configured the PPL with assertions turned on, 
which I would recommend in such a debugging phase.

Good luck and keep us informed,
Enea.