From 45d300e09edb5e00206bd53693005483cf44410f Mon Sep 17 00:00:00 2001
From: Hojoon Ji <sleeperbus@gmail.com>
Date: Sun, 13 Apr 2014 23:23:22 +0900
Subject: [PATCH 1/2] first save

---
 cachematrix.R | 35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..17e6e585c7c 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,34 @@
-## Put comments here that give an overall description of what your
-## functions do
+###############################################################################
+#   Calculate inverse matrix and cache the result for reusablity
+###############################################################################
 
-## Write a short comment describing this function
 
+## Initialize orgMat variable to x as soon as this object is created.
 makeCacheMatrix <- function(x = matrix()) {
-
+    orgMat <- NULL
+    inverseMat <- NULL
+    setMat <- function(mat) {
+        orgMat <<- mat
+        inverseMat <<- NULL
+    }
+    getMat <- function() orgMat
+    setInverseMat <- function(mat) inverseMat <<- mat
+    getInverseMat <- function() inverseMat
+    setMat(x)
+    list(setMat = setMat, getMat = getMat, setInverseMat = setInverseMat,
+         getInverseMat = getInverseMat)    
 }
 
-
-## Write a short comment describing this function
-
+# return cache data if exists
+# otherwise use solve function to calculate inverse matrix and save to
+# caller object
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    inverseMat <- x$getInverseMat()
+    if (!is.null(inverseMat)) {
+        message("getting from cache")
+        return (inverseMat)
+    }
+    x$setInverseMat(solve(x$getMat()))
+    inverseMat <- x$getInverseMat()
+    inverseMat
 }

From b35e81a04b4208e7816657ec99b4bcc59ee3b10a Mon Sep 17 00:00:00 2001
From: Hojoon Ji <sleeperbus@gmail.com>
Date: Sun, 13 Apr 2014 23:35:54 +0900
Subject: [PATCH 2/2] Add new comments

---
 cachematrix.R | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/cachematrix.R b/cachematrix.R
index 17e6e585c7c..2fe84d4a862 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -3,18 +3,26 @@
 ###############################################################################
 
 
-## Initialize orgMat variable to x as soon as this object is created.
+# Initialize orgMat variable to x as soon as this object is created.
 makeCacheMatrix <- function(x = matrix()) {
     orgMat <- NULL
     inverseMat <- NULL
+    
+    # save original matrix
     setMat <- function(mat) {
         orgMat <<- mat
         inverseMat <<- NULL
     }
+    # return original matrix
     getMat <- function() orgMat
+    # save inverse matrix
     setInverseMat <- function(mat) inverseMat <<- mat
+    # return inverse matrix
     getInverseMat <- function() inverseMat
+    
+    # initialize orgMat var
     setMat(x)
+    
     list(setMat = setMat, getMat = getMat, setInverseMat = setInverseMat,
          getInverseMat = getInverseMat)    
 }