def datapoint_indices_for_tensor(self, tensor_index):
        """ Returns the indices for all datapoints in the given tensor. """
        if tensor_index >= self._num_tensors:
            raise ValueError('Tensor index %d is greater than the number of tensors (%d)' %(tensor_index, self._num_tensors))
        return self._file_num_to_indices[tensor_index]
Returns the indices for all datapoints in the given tensor.