Two algorithms I coded as part of Ying Liu's Fall 2017 Applied Data Science course at Columbia.
SimRank is coded in R, and based on this paper by Glen Jeh and Jennifer Widom, and also based on Colin Su's Python implementation.
Mean Squared Difference was coded in Python, and was optimized for parallel processing.
The data should be a sparse matrix. For SimRank the data should be 1s and 0s. For Mean Squared Difference, the data can be the scores.