sparse matrix memory

Question

I need to implement a sparse matrix as efficiently memory-wise as I can in Java.I receive a matrix with more 0 than other values and I need to save it efficiently.I was thinking of using an array with an Object containing value and position composed of the line*max nr of columns+the column.

Answer 1

Depends entirely on what operations you are doing on said matrix which implementation will suit your needs.

e.g. if all you are doing is updating values and retrieving them a Map<Point, Value> will work. Addition is also easy in this, but multiplication becomes very difficult.