Measuring Context Similarity using Pearson’s correlation coefficient

Hi I am trying to implement this algorithm using Matlab. If anyone cares to help me as I am totally alone and in need of dire assistance!

Basically this algorithm denotes the rating given by the user u on item i in context x as ru,i,x, and formulatethe similarity weight for two different context variables, x and y for item i. It then returns the relevance of the two context values in a context dimension Ct.