When describing an error surface where the gradient changes underneath our feet as we move in the direction of steepest descent, the Hessian matrix H is said to be ______.

Deep learning is a type of machine learning, which is a subset of artificial intelligence. Machine learning is about computers being able to think and act with less human intervention; deep learning is about computers learning to think using structures modeled on the human brain.

Practical examples of deep learning are Virtual assistants, vision for driverless cars, money laundering, face recognition and many more.