Keras backend options

Keras is a model-level library that provides high-level blocks for the development of deep learning models. Keras developers have focused their efforts on creating high-level models by neglecting low-level operations such as tensor products, convolutions, and so on. These operations have been entrusted to specialized and well-optimized tensor manipulation libraries that already exist, thus acting as a backend engine for Keras. Several backend engines can be connected perfectly to Keras. Actually, Keras has three backend implementations available—TensorFlow, Theano, and Microsoft Cognitive Toolkit (CNTK).