Created the two functions requested

Author: Massimo Biancalani

cachematrix.R

@@ -1,15 +1,56 @@
-## Put comments here that give an overall description of what your
-## functions do
+#' @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.
 
-## Write a short comment describing this function
 
+#' 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)
 }
 
-
-## Write a short comment describing this function
-
+#' 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, ...) {
-        ## Return a matrix that is the inverse of '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
 }