code: def test_gpu4_gibbs_chain(self):
      rng = np.random.RandomState(utt.fetch_seed())
      v_vsample = np.array(
          rng.binomial(
              1,
              0.5,
              size=(3, 20),
          ),
          dtype="float32",
      )
      vsample = theano.shared(v_vsample)
      trng = theano.sandbox.rng_mrg.MRG_RandomStreams(utt.fetch_seed())
  
      def f(vsample_tm1):
          return (
              trng.binomial(
                  vsample_tm1.shape, n=1, p=0.3, dtype="float32"
              )
              * vsample_tm1
          )
  
      theano_vsamples, updates = theano.scan(
          f,
          [],
          vsample,
          [],
          n_steps=10,
          truncate_gradient=-1,
          go_backwards=False,
          mode=mode_with_gpu,
      )
      my_f = theano.function(
          [],
          theano_vsamples[-1],
          updates=updates,
          allow_input_downcast=True,
          mode=mode_with_gpu,
      )
  
      # I leave this to tested by debugmode, this test was anyway
      # more of does the graph compile kind of test
      my_f()
  
file_path: Theano/theano/gpuarray/tests/test_scan.py
imports: from __future__ import absolute_import, print_function, division
  from unittest import TestCase
  import numpy
  from six.moves import xrange
  import theano
  from theano.tests import unittest_tools
  import theano.sandbox.rng_mrg
  from ..basic_ops import GpuFromHost, HostFromGpu
  from ..elemwise import GpuElemwise
  from .config import mode_with_gpu, test_ctx_name
label_desc: Use image node_id 5 for calling the T_Scan obj's underlying member method code with example usage: obj.test_gpu4_gibbs_chain() and returns: unknown