Function blas::c::dgemv

pub fn dgemv(layout: Layout,
             transa: Transpose,
             m: i32,
             n: i32,
             alpha: f64,
             a: &[f64],
             lda: i32,
             x: &[f64],
             incx: i32,
             beta: f64,
             y: &mut [f64],
             incy: i32)