code: def cublasZgbmv(handle, trans, m, n, kl, ku, alpha, A, lda, 
                  x, incx, beta, y, incy):
      
  
      status = _libcublas.cublasZgbmv_v2(handle,
                                         trans, m, n, kl, ku,
                                         ctypes.byref(cuda.cuDoubleComplex(alpha.real,
                                                                           alpha.imag)),
                                         int(A), lda, int(x), incx,
                                         ctypes.byref(cuda.cuDoubleComplex(beta.real,
                                                                           beta.imag)),
                                int(y), incy)
      cublasCheckStatus(status)
docs: Matrix-vector product for complex general banded matrix.