cachematrix.R

#' @title Store in the cache matrix and the inverse.
#' @description
##  The following functions cache the matrix inverse given a 
##  previous matrix. They allow avoid useless calculations.


#' makeCacheMatrix
#' \code{makeCacheMatrix} returns a special a list containing a function to retieve cached values
#' 
#' @param x matrix to cache
#' @return list of methods 
#' set the value of the matrix
#' get the value of the matrix
#' setInverse the value of the inverse of the matrix
#' getInverse the value of the inverse of the matrix
#' @examples
#' my_matrix <- matrix(c(1,2,2,1), nrow=2, ncol=2)
#' my_matrix_cached <- makeCacheMatrix(my_matrix)
makeCacheMatrix <- function(x = matrix()) {
        m <- NULL
        set <- function(y) {
                x <<- y
                m <<- NULL
        }
        get <- function() x
        setInverse <- function(inverse) m <<- inverse
        getInverse <- function() m
        list(set = set, get = get,
             setInverse = setInverse,
             getInverse = getInverse)
}

#' cacheSolve
#' \code{cacheSolve} returns Return a matrix that is the inverse of 'x'. 
#' 
#' @param the \code{makeCacheMatrix} to find inverse 
#' @param ... expressions evaluated in the context of \code{solve}  
#' @return the inverse matrix of 'x' 
#' @examples
#' my_matrix <- matrix(c(1,2,2,1), nrow=2, ncol=2)
#' my_matrix_cached <- makeCacheMatrix(my_matrix)
#' cacheSolve(my_matrix_cached)
cacheSolve <- function(x, ...) {
        
        m <- x$getInverse()
        # if the matrix is cached return the inverse
        # otherwise compute the inverse and store it in the cache
        if(!is.null(m)) {
                message("getting cached data")
                return(m)
        }
        data <- x$get()
        m <- solve(data, ...)
        x$setInverse(m)
        m
}