Sparse matrix format in armPL

I'm new with armPL and I have some questions about the sparse matrix formats.

1) I know the COO format is not efficient for sparse matrix operations. If I build COO sparse matrix in armPL, the optimization function that I have to call before each operation makes the internal format efficient, or is it better to create the matrix in CSR format?

2) In case of better performance with CSR format, if I have to convert a COO matrix into CSR matrix can I use the export functions (like armpl_spmat_export_csr_s) for building the input data of CSR matrix?