pub unsafe extern "C" fn dgemv_(
trans: *const c_char,
m: *const blas_int,
n: *const blas_int,
alpha: *const f64,
a: *const f64,
lda: *const blas_int,
x: *const f64,
incx: *const blas_int,
beta: *const f64,
y: *mut f64,
incy: *const blas_int,
)