In neural networks tutorial:

http://pytorch.org/tutorials/beginner/blitz/neural_networks_tutorial.html

Just below the picture, obviously "weight = weight + learning_rate * gradient" should be "weight = weight - learning_rate * gradient", which is the gradient descent algorithm.