Function mv 

pub fn mv<T: ComplexScalar>(
    op: Trans,
    alpha: T,
    a: &ComplexSparseMatrix<T>,
    descr: &MatDescr,
    x: &[T],
    beta: T,
    y: &mut [T],
) -> Result<()>

Compute y := α · op(A) · x + β · y for a complex CSR matrix A.