From 8ca98ace0a036a395d59225d2e4c9a25539b81ac Mon Sep 17 00:00:00 2001
From: Christopher Roach <vthakr@gmail.com>
Date: Mon, 19 Jan 2015 15:03:39 -0800
Subject: [PATCH 1/3] Making git repo an RStudio project

---
 .gitignore                   |  3 +++
 ProgrammingAssignment2.Rproj | 13 +++++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 ProgrammingAssignment2.Rproj

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000000..807ea251739
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+.Rproj.user
+.Rhistory
+.RData
diff --git a/ProgrammingAssignment2.Rproj b/ProgrammingAssignment2.Rproj
new file mode 100644
index 00000000000..8e3c2ebc99e
--- /dev/null
+++ b/ProgrammingAssignment2.Rproj
@@ -0,0 +1,13 @@
+Version: 1.0
+
+RestoreWorkspace: Default
+SaveWorkspace: Default
+AlwaysSaveHistory: Default
+
+EnableCodeIndexing: Yes
+UseSpacesForTab: Yes
+NumSpacesForTab: 2
+Encoding: UTF-8
+
+RnwWeave: Sweave
+LaTeX: pdfLaTeX

From 1eb4341b4f0b3d2b4d88916e742c063f0d1738fc Mon Sep 17 00:00:00 2001
From: Christopher Roach <vthakr@gmail.com>
Date: Mon, 19 Jan 2015 15:04:03 -0800
Subject: [PATCH 2/3] Changes for Assignment 2

---
 cachematrix.R | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..93211575dcd 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -4,12 +4,31 @@
 ## Write a short comment describing this function
 
 makeCacheMatrix <- function(x = matrix()) {
-
+  i <- NULL
+  
+  set <- function(y) {
+    message("clearing the cached inverse")
+    i <<- NULL
+    x <<- y
+  }
+  get <- function() x
+  setinverse <- function(inverse) i <<- inverse
+  getinverse <- function() i
+  list(set = set, get = get, setinverse = setinverse, getinverse = getinverse)
 }
 
 
 ## Write a short comment describing this function
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of '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 4facc0fd3fdc14de38ef07904e4d830303e402d4 Mon Sep 17 00:00:00 2001
From: Christopher Roach <vthakr@gmail.com>
Date: Mon, 19 Jan 2015 15:18:18 -0800
Subject: [PATCH 3/3] Added some comments explaining the code

---
 cachematrix.R | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index 93211575dcd..c4cf826b08a 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,12 +1,16 @@
-## Put comments here that give an overall description of what your
-## functions do
+## The makeCacheMatrix and cacheSolve functions work together to create a 
+## special matrix wrapper object that can cache its own inverse value.
 
-## Write a short comment describing this function
+## The makeCacheMatrix function creates a special object that wraps a matrix
+## object and provides accessor functions to the matrix object and the cached
+## inverse of the matrix. 
 
 makeCacheMatrix <- function(x = matrix()) {
   i <- NULL
   
   set <- function(y) {
+    # Clear the cached inverse whenever we update the matrix object to make 
+    # sure we don't return an incorrect inverse.
     message("clearing the cached inverse")
     i <<- NULL
     x <<- y
@@ -18,7 +22,9 @@ makeCacheMatrix <- function(x = matrix()) {
 }
 
 
-## Write a short comment describing this function
+## The cacheSolve function calculates the inverse of the given matrix and 
+## caches it on that object. If the inverse of the give matrix is already 
+## cached it returns instead of calculating it anew.
 
 cacheSolve <- function(x, ...) {
   ## Return a matrix that is the inverse of 'x'