Function sprs::prod::csr_mul_csvec

pub fn csr_mul_csvec<N, I>(
    lhs: CsMatViewI<N, I>, 
    rhs: CsVecViewI<N, I>
) -> CsVecI<N, I> where
    N: Copy + Num + Sum,
    I: SpIndex, 

CSR-vector multiplication