code: def test_gemv(dtype, opA, transA, order):
      gemv = _gemv_memview[_numpy_to_cython(dtype)]
  
      rng = np.random.RandomState(0)
      A = np.asarray(
          opA(rng.random_sample((20, 10)).astype(dtype, copy=False)),
          order=ORDER[order],
      )
      x = rng.random_sample(10).astype(dtype, copy=False)
      y = rng.random_sample(20).astype(dtype, copy=False)
      alpha, beta = 2.5, -0.5
  
      expected = alpha * opA(A).dot(x) + beta * y
      gemv(transA, alpha, A, x, beta, y)
  
      assert_allclose(y, expected, rtol=RTOL[dtype])
  
file_path: scikit-learn/sklearn/utils/tests/test_cython_blas.py
imports: import numpy
  import pytest
  from sklearn.utils._cython_blas import ColMajor, NoTrans, RowMajor, Trans, _asum_memview, _axpy_memview, _copy_memview, _dot_memview, _gemm_memview, _gemv_memview, _ger_memview, _nrm2_memview, _rot_memview, _rotg_memview, _scal_memview
  from sklearn.utils._testing import assert_allclose
label_desc: Use image node_id 11 for calling a global function with example usage: test_gemv(dtype, opA, transA, order) without return types