From ca44e775bd00e66836f5a4a6dc65d8fbb984a12e Mon Sep 17 00:00:00 2001
From: Sumahitha <sumakasi@live.com>
Date: Tue, 22 Apr 2014 22:12:36 -0700
Subject: [PATCH] Completing ProgAssignment2 to create cached inverse of a
 matrix

---
 cachematrix.R | 73 ++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 67 insertions(+), 6 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..e90adc993ba 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,76 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Description: Create functions that will help cache the inverse of a matrix
+## This will be achieved with 2 functions. 
 
-## Write a short comment describing this function
+## FunctionName: makeCacheMatrix
+## Arguments: x is a matrix that is invertible (non-singular)
+## Returns : list of functions 
+##
+## Description: makeCacheMatrix creates a list of functions that 
+##  1. set - sets the matrix provided as argument 
+##  2. get - gets the  matrix
+##  3. setInverse - caches the provided inverse
+##  4. getInverse - returns the cached inverse
 
 makeCacheMatrix <- function(x = matrix()) {
-
+    inv <- NULL
+    ##  1. set - sets the matrix provided as argument 
+    set <- function(y) 
+    {
+        x <<- y
+        inv <<- NULL
+    }
+    ##  2. get - gets the  matrix    
+    get <- function() 
+    {
+        x
+    }
+    ##  3. setInverse - caches the provided inverse
+    setInverse <- function(inverse) 
+    {
+        inv <<- inverse
+    }
+    ##  4. getInverse - returns the cached inverse    
+    getInverse <- function()
+    {
+        inv
+    }
+    ## Creates a list of above functions and returns it
+    list(set = set, get = get,
+         setInverse = setInverse,
+         getInverse = getInverse)
 }
 
 
-## Write a short comment describing this function
+## FunctionName: cacheSolve
+## Arguments: x is a matrix that is of type makeCacheMatrix
+## Returns : inverse of the provided matrix
+##
+## Description: cacheSolve returns the cached inverse of the matrix if available
+##              if not calculates the inverse, caches it and returns the 
+##              inverse of the matrix
+
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    
+    ## Get the cached inverse
+    inv <- x$getInverse()
+    
+    ## Check if cached inverse is valid
+    if(!is.null(inv)) {
+        message("getting cached data")
+        # If valid, return cached inverse
+        return(inv)
+    }
+    
+    ## If not, get the matrix
+    data <- x$get()
+    
+    ## Calculate the inverse of the matrix
+    inv <- solve(data, ...)
+    
+    ## Cache the inverse of the matrix
+    x$setInverse(inv)
+    
+    ## Return a matrix that is the inverse of 'x'
+    inv
 }