Linear algebra with sparse tensors

Hi,
I wonder if exists a linear algebra that works with sparse tensors, or if exist some workarounds to avoid transformation to full matrices (in particular, methods to solve linear systems).
I would like to use TensorFlow on large matrices (dense size of orders 500000X500000) but with a sparse pattern (e.g. with ~ 3500000 nonzero elements).

Thanks,

Cesare