code: def grab_cpu_scalar(v, nd):
      """
      Get a scalar variable value from the tree at `v`.
  
      This function will dig through transfers and dimshuffles to get
      the constant value. If no such constant is found, it returns None.
  
      Parameters
      ----------
      v
          Theano variable to extract the constant value from.
      nd : int
          Expected number of dimensions for the variable (for
          broadcasted constants).
  
      """
      if v.owner is not None:
          n = v.owner
          if (
              isinstance(n.op, (GpuDimShuffle, DimShuffle))
              and n.op.new_order == ("x",) * nd
          ):
              return grab_cpu_scalar(n.inputs[0], n.inputs[0].ndim)
          elif isinstance(n.op, (GpuFromHost, HostFromGpu)):
              return grab_cpu_scalar(n.inputs[0], nd)
          else:
              return None
      else:
          if (
              isinstance(v, Constant)
              and v.broadcastable == (True,) * nd
          ):
              return v.dimshuffle(())
  
file_path: Theano/theano/gpuarray/opt_util.py
imports: from __future__ import absolute_import, print_function, division
  from functools import wraps
  import numpy
  from theano import tensor, scalar, Constant
  from theano.gof import local_optimizer
  from theano.gof.opt import inherit_stack_trace
  from theano.tensor import DimShuffle, get_scalar_constant_value, NotScalarConstantError
  from .basic_ops import GpuFromHost, HostFromGpu, GpuAllocEmpty, GpuReshape
  from .elemwise import GpuDimShuffle, GpuElemwise
label_desc: Use image node_id 1 for calling a global function with example usage: grab_cpu_scalar(v, nd) and returns: grab_cpu_scalar, v, grab_cpu_scalar, None