code: func (co *Context) GetReductionIndicesSize(reduceTensorDesc *Reduction, aDesc *TensorDescriptor, cDesc *TensorDescriptor) (sizeInBytes uintptr, err error) {
  	var sizeInBytesC C.size_t
  	// call cudnnGetReductionIndicesSize
  	err = result(C.cudnnGetReductionIndicesSize(co.internal, reduceTensorDesc.internal, aDesc.internal, cDesc.internal, &sizeInBytesC))
  	sizeInBytes = uintptr(sizeInBytesC)
  	return
  }
docs: // GetReductionIndicesSize is a helper function to return the minimum size of the index space to be passed to the reduction given the input and output tensors.