In this work an algorithm for the evaluation of N-dimensional piecewise-linear (PWL) functions is presented. The type of PWL representation which is considered is the denominated simplicial representation that is defined in a N-dimensional domain partitioned by hyperplanes and divided into simplices. The algorithm performs a local function computation into the specific simplex where the evaluation point is found. The simplicial PWL (S-PWL) interpolating equations are collected into a matrix system which adopts the form of the decomposed PWL models. The algorithm works directly with this decomposed model and determines the value of the S-PWL function simply by its values on the vertices.