code: def test_extractdiag_opt(self):
      x = tensor.matrix()
      fn = theano.function(
          [x], tensor.ExtractDiag()(x), mode=mode_with_gpu
      )
      assert any(
          [
              isinstance(node.op, GpuExtractDiag)
              for node in fn.maker.fgraph.toposort()
          ]
      )
  
imports: from __future__ import absolute_import, print_function, division
  import numpy
  import unittest
  import theano
  from theano import tensor
  from theano.compile import DeepCopyOp
  from theano.tensor.tests import test_subtensor, test_basic
  from theano.tests import unittest_tools
  from ..basic_ops import HostFromGpu, GpuFromHost, GpuContiguous
  from ..elemwise import GpuDimShuffle
  from ..subtensor import GpuIncSubtensor, GpuSubtensor, GpuAdvancedSubtensor1, GpuAdvancedSubtensor, GpuAdvancedBooleanSubtensor, GpuAdvancedIncSubtensor, GpuAdvancedIncSubtensor1, GpuAdvancedIncSubtensor1_dev20, GpuExtractDiag, GpuAllocDiag
  from ..type import gpuarray_shared_constructor
  from .config import mode_with_gpu, test_ctx_name
label_desc: Use image node_id 1 for calling the test_gpuextractdiag obj's underlying member method code with example usage: obj.test_extractdiag_opt() without return types