A = sprand(10, 10, 0.5)
block_size_rows = 2
block_size_columns = 2
# Creating block sparse matrix
B = SparseMatrixBSC(A, block_size_rows, block_size_columns)
# BlockMatrix times vector
B * rand(size(B,1))
# Convert back to CSC
A2 = SparseMatrixCSC(B)
# Check roundtrip
A == A2