#NEWLINE# def bprop( self , y_grad ) : #NEWLINE# #INDENT# ( _ , x_grad ) = self . conv_op . bprop ( self . _tmp_x , self . weights . array , y_grad , to_imgs = self . bprop_to_x , filters_d = x_grad . weights . grad_array ) #NEWLINE# ca . sum ( ca . sum ( y_grad , axis = ( 2 , 3 ) , keepdims = True ) , axis = 0 , keepdims = True , out = self . bias . grad_array ) #NEWLINE# return x_grad