rank(H) = 0 and nonzeros(H)> matrix nonzeros?

[ztdepztdep]

I construct the Matrix with
auto H = strumpack::structured::construct_from_dense(D, options);
where D is my dense matrix which has a dimension of 81x81=6561.
but the it shows the infor of

• nonzeros(H) = 7537 and - rank(H) = 0
  7537>6551.
  I think it gives error results. Could you please give me some advices.

[pghysels]

That is indeed strange.
The number of nonzeros could be larger than n^2 if the rank is large, but it's zero in this case.
Is this on a single MPI rank?
Did you check the accuracy of the compressed matrix?