From b10df10f25d9222a5de397fcb1d55c055fe36144 Mon Sep 17 00:00:00 2001
From: Alain Domissy <alaindomissy@gmail.com>
Date: Fri, 25 Apr 2014 17:11:03 -0700
Subject: [PATCH] first commit

---
 cachematrix.R | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..2cb1f8f8214 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,33 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
+## This file provides a pair of functions that cache the inverse of a matrix.
 
+## This function creates a special "matrix" object that can cache its inverse.
 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
-
+## 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 this function 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'
+    m <- x$getinverse()
+    if(!is.null(m)) {
+        message("getting cached data")
+        return(m)
+    }
+    data <- x$get()
+    m <- solve(data, ...)
+    x$setinverse(m)
+    m
 }