Mean of sum of gradients in Grad-CAM?

[bryanbocao]

I got some confusions in Grad-CAM weight calculation, it would be great to clarify that:
In the code

pytorch-grad-cam/pytorch_grad_cam/grad_cam.py

Line 16 in 58a565a

def get_cam_weights(self,

    def get_cam_weights(self,
                        input_tensor,
                        target_layer,
                        target_category,
                        activations,
                        grads):
        return np.mean(grads, axis=(2, 3))

indicates that it is the mean of gradients, but equation (11) in the paper https://arxiv.org/pdf/1610.02391.pdf is the sum of the partial gradients. I am confused. Thanks!

[bryanbocao]

Equation (1) in the paper https://arxiv.org/pdf/1610.02391.pdf suggests taking a mean instead of sum.