Performance issues sparse/ultra-sparse binary read

Recent experiments with PageRank (20 iterations) on a 1M x 1M, sp=0.001 input showed that the actual iterations are indeed very fast, at peak memory bandwidth (i.e., ~500ms per iteration in CP only) but the initial read is unnecessarily slow, and thus dominating the entire execution time. For example, in this scenario, the read took 41s.

This task aims to improve the read performance of sparse and ultra-sparse matrices into CP.