tanh.py 文件源码

def backward_gpu(self, x, gy):
        if (cuda.cudnn_enabled and self.use_cudnn and
                (_cudnn_version >= 3000 or x[0].dtype != numpy.float16)):
            gx = cudnn.activation_backward(x[0], self.y, gy[0], _mode)
        else:
            gx = cuda.elementwise(
                'T y, T gy', 'T gx',
                'gx = gy * (1 - y * y)',
                'tanh_bwd')(self.y, gy[0])
        return gx,