Published on: July 13, 2021
RMSprop is an unpublished, adaptive learning rate optimization algorithm first proposed by Geoff Hinton in lecture 6 of his online class "Neural Networks for Machine Learning". RMSprop and Adadelta have been developed independently around the same time, and both try to resolve Adagrad's diminishing learning rate problem. 
The difference between Adadelta and RMSprop is that Adadelta removes the learning rate
 Sebastian Ruder (2016). An overview of gradient descent optimization algorithms. arXiv preprint arXiv:1609.04747.