From b677ce8caf15b1c598107fc8c0587ce9bc58398e Mon Sep 17 00:00:00 2001
From: Mathew <mathewd@bo-c02p5ee9g3qc.home>
Date: Sun, 26 Apr 2015 05:40:15 -0400
Subject: [PATCH 1/2] Programming Assignment 2 initial commit

---
 cachematrix.R | 42 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 7 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..fc2d1721266 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,43 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Provides functions to find inverse of a matrix. Finding inverse
+## of a matrix is expensive. This optimized function computes the 
+## inverse and cache the result for subsequent calls. 
 
-## Write a short comment describing this function
+## This function crates a special matrix object that can
+## can cache it's inverse
 
 makeCacheMatrix <- function(x = matrix()) {
-
+    ## variable to keep the inverse and initialized to NULL
+    i <- NULL
+    ## function to cache matrix 
+    set <- function(y) {
+        x <<- y
+        i <<- NULL
+    }
+    ## function to return matrix
+    get <- function() x
+    ## function to cache inverse of the matrix
+    setinverse <- function(inverse) i <<- inverse
+    ## function to return the inverse
+    getinverse <- function() i
+    list(set = set, get = get,
+         setinverse = setinverse,
+         getinverse = getinverse)    
 }
 
-
-## Write a short comment describing this function
+## This function computes the inverse of special matrix created by 
+## makeCacheMatrix above. If inverse is already created, this function 
+## returns the inverse from cahce.
+## Return a matrix that is the inverse of 'x'. This method assumes
+## matrix 'x' is squre invertible, otherwise throws error.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    i <- x$getinverse()
+    if(!is.null(i)){
+        message("getting cached data")
+        return(i)
+    }
+    data <- x$get()
+    i <- solve(data, ...)
+    x$setinverse(i)
+    i
 }

From e5f2fa4bffa27674bcd15fd5e81644a30bf550e5 Mon Sep 17 00:00:00 2001
From: Mathew <mathewd@bo-c02p5ee9g3qc.home>
Date: Sun, 26 Apr 2015 05:50:57 -0400
Subject: [PATCH 2/2] more comments

---
 cachematrix.R | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index fc2d1721266..a4ad915ae5b 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -4,7 +4,6 @@
 
 ## This function crates a special matrix object that can
 ## can cache it's inverse
-
 makeCacheMatrix <- function(x = matrix()) {
     ## variable to keep the inverse and initialized to NULL
     i <- NULL
@@ -29,15 +28,22 @@ makeCacheMatrix <- function(x = matrix()) {
 ## returns the inverse from cahce.
 ## Return a matrix that is the inverse of 'x'. This method assumes
 ## matrix 'x' is squre invertible, otherwise throws error.
-
 cacheSolve <- function(x, ...) {
+    ## First check if inverse of x is already computed
     i <- x$getinverse()
     if(!is.null(i)){
+        ## Inverse of x is already compted. So, show a message
+        ## and return inverse from cache 
         message("getting cached data")
         return(i)
     }
+    ## Inverse is not in cache. Get the matrix to compute inverse
     data <- x$get()
+    ## FInd the inverse by calling solve()
+    ## Solve computes inverse only for squre invertible matrix
     i <- solve(data, ...)
+    ## Cache the result
     x$setinverse(i)
+    ## return the inverse
     i
 }