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

pghysels / STRUMPACK

Structured Matrix Package (LBNL)

http://portal.nersc.gov/project/sparse/strumpack/

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rank(H) = 0 and nonzeros(H)> matrix nonzeros? #81

Open ztdepztdep opened 1 year ago

ztdepztdep commented 1 year ago

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 commented 1 year ago

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?