assignement inverse matrix cached

Author: Yvan Wibaux

cachematrix.R

@@ -1,15 +1,37 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Matrix inversion is usually a costly computation and there may be some benefit
+## to caching the inverse of a matrix rather than compute it repeatedly
 
-## Write a short comment describing this function
+## This function creates a special "matrix" object that can cache its inverse.
 
 makeCacheMatrix <- function(x = matrix()) {
-
+    inverse <- NULL
+    set <- function(y) {
+        x <<- y
+        inverse <<- NULL
+    }
+    get <- function() x
+    setInverse <- function(i) inverse <<- i
+    getInverse <- function() inverse
+    list(set = set, get = get,
+         setInverse = setInverse,
+         getInverse = getInverse)
 }
 
 
-## Write a short comment describing this function
+## This function computes the inverse of the special "matrix" 
+## returned by makeCacheMatrix above. 
+## If the inverse has already been calculated (and the matrix has not changed), 
+## then the cachesolve should retrieve the inverse from the cache.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    ## Return a matrix that is the inverse of 'x'
+    inverse <- x$getInverse()
+    if(!is.null(inverse)) {
+        message("getting cached data")
+        return(inverse)
+    }
+    data <- x$get()
+    inverse <- solve(x$get(), ...)
+    x$setInverse(inverse)
+    inverse
 }