From 2e577e326f3c81d320f1b78f278a072850c0a051 Mon Sep 17 00:00:00 2001
From: Manoj Xavier <xpmanoj2@gmail.com>
Date: Wed, 20 Aug 2014 00:38:29 +0800
Subject: [PATCH 1/2] Added completed cachematrix.R

---
 cachematrix.R | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..330c5e84202 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -4,6 +4,17 @@
 ## Write a short comment describing this function
 
 makeCacheMatrix <- function(x = matrix()) {
+        inv <- NULL
+        set <- function(y) {
+                x <<- y
+                inv <<- NULL
+        }
+        get <- function() x
+        setinverse <- function(solve) inv <<- solve
+        getinverse <- function() inv
+        list(set = set, get = get,
+             setinverse = setinverse,
+             getinverse = getinverse)
 
 }
 
@@ -12,4 +23,17 @@ makeCacheMatrix <- function(x = matrix()) {
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'
+        inv <- x$getinverse()
+        if(!is.null(inv)) {
+                message("getting cached data")
+                return(inv)
+        }
+        data <- x$get()
+        inv <- solve(data, ...)
+        x$setinverse(inv)
+        inv
 }
+
+a = matrix( c(4,10,23,12), nrow=2, ncol=2) 
+mat <- makeCacheMatrix(a)
+cacheSolve(mat)

From 6b44e4ac0c0df0b315e4222a6bd9f94a6fb306a4 Mon Sep 17 00:00:00 2001
From: Manoj Xavier <xpmanoj2@gmail.com>
Date: Wed, 20 Aug 2014 01:05:31 +0800
Subject: [PATCH 2/2] Added comments

---
 cachematrix.R | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index 330c5e84202..b8f2d3d49ea 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,7 +1,11 @@
-## Put comments here that give an overall description of what your
-## functions do
+## makeCacheMatrix creates special "matrix" whereas the cacheSolve returns the inverse of the
+## matrix from cache, if it exists there. if not, it computes the inverse and returns it.
 
-## Write a short comment describing this function
+## makeCacheMatrix creates a special "matrix" ,which is a list containing a function to
+## 1. set the value of the matrix
+## 2. get the value of the matrix
+## 3. set the inverse of the matrix
+## 4. get the inverse of the matrix
 
 makeCacheMatrix <- function(x = matrix()) {
         inv <- NULL
@@ -19,7 +23,8 @@ makeCacheMatrix <- function(x = matrix()) {
 }
 
 
-## Write a short comment describing this function
+## cacheSolve returns the inverse of a matrix if it exists in the cache. 
+## if not, it computes the inverse and returns it
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'
@@ -34,6 +39,8 @@ cacheSolve <- function(x, ...) {
         inv
 }
 
+## Test both functions with test data
 a = matrix( c(4,10,23,12), nrow=2, ncol=2) 
 mat <- makeCacheMatrix(a)
 cacheSolve(mat)
+cacheSolve(mat)