Takes a value x in the subspace of not fixed dimensions and expands it with the values of the fixed ones.
        :param x: input vector to be expanded by adding the context values

def _expand_vector(self,x):
        '''
        Takes a value x in the subspace of not fixed dimensions and expands it with the values of the fixed ones.
        :param x: input vector to be expanded by adding the context values
        '''
        x = np.atleast_2d(x)
        x_expanded = np.zeros((x.shape[0],self.space.model_dimensionality))
        x_expanded[:,np.array(self.noncontext_index).astype(int)]  = x
        x_expanded[:,np.array(self.context_index).astype(int)]  = self.context_value
        return x_expanded