# Diagnostics¶

If you run into problems, the first thing to check is whether the filtration you are giving to Dionysus is a simplicial complex, using is_simplicial():

>>> f = d.Filtration([([0], 1.), ([0,1], 2.)])
>>> d.is_simplicial(f)
False


You can also ask this function to report problems it finds:

>>> d.is_simplicial(f, report = True)
<1> 0 in boundary of <0,1> 2 not found in the filtration
False