# Information Theory-entropy Tools

Required to prove the Shannon coding theorems. These tools form an area com- mon to ergodic theory and information theory and comprise several quantitative.

The cross-entropy between two probability distributions p and q.

Shannon’s entropy quantifies the quantity of data during a variable, thus providing the inspiration for a theory around the notion of information.

Online calculator. This online calculator calculates joint entropy of two discrete random variables given a joint distribution table (X, Y) ~ p.