From 3790cd879e73ec8dc7afef912c97b1940116cf53 Mon Sep 17 00:00:00 2001
From: Fraser Hewson <fraser.hewson@gmail.com>
Date: Sun, 24 Aug 2014 12:26:48 +0200
Subject: [PATCH 1/5] Add .gitignore and project file

---
 .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 f54b28ad9a75d8f9ca99831d49e67e5704d8477c Mon Sep 17 00:00:00 2001
From: Fraser Hewson <fraser.hewson@gmail.com>
Date: Sun, 24 Aug 2014 12:29:00 +0200
Subject: [PATCH 2/5] implemented makeCacheMatrix and cacheSolve

---
 cachematrix.R | 39 ++++++++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..3c1d664d5c9 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,40 @@
-## Put comments here that give an overall description of what your
-## functions do
+## The following functions allow for the creation of a matrix where the invers
+## is cached after it has been calculated. This prevents the re-execution 
+## of a rather expensive operation.
 
-## Write a short comment describing this function
-
-makeCacheMatrix <- function(x = matrix()) {
+## makeCacheMatrix creates a 'special' matrix object that stores the 
+## matrix as well as its inverce. Use this matrix with cacheSolve() 
 
+makeCacheMatrix <- function(m.orig = matrix()) {
+  m.result <- NULL
+  set <- function(m.set) {
+    m.orig <<- m.set
+    m.result <<- NULL
+  }
+  get <- function() m.orig
+  setresult <- function(result) m.result <<- result
+  getresult <- function() m.result
+  list(set = set, get = get,
+       setresult = setresult,
+       getresult = getresult)
 }
 
 
-## Write a short comment describing this function
+## cacheSolve finds the inverse of the matrix created by makeCacheMatrix(). 
+## The inverse of the matrix is only calculated once. On subsequent calls, the 
+## cached result is used.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+  mcache <- NULL
+  mlist <- x
+  
+  m <- mlist$getresult()
+  if(!is.null(m)){
+    print("using cached data")
+    return(m)
+  }
+  data <- mlist$get()
+  result <- solve(data, ...)
+  mlist$setresult(result)
+  result
 }

From 50363f2e8dacaad48a1d9ee8afd0c1fc1e2ad266 Mon Sep 17 00:00:00 2001
From: Fraser Hewson <fraser.hewson@gmail.com>
Date: Sun, 24 Aug 2014 12:39:03 +0200
Subject: [PATCH 3/5] Change print to message

---
 cachematrix.R | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cachematrix.R b/cachematrix.R
index 3c1d664d5c9..d5b101e25e2 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -30,7 +30,7 @@ cacheSolve <- function(x, ...) {
   
   m <- mlist$getresult()
   if(!is.null(m)){
-    print("using cached data")
+    message("Using cached data")
     return(m)
   }
   data <- mlist$get()

From 94afcbb87938612a09ad38cfbf6ff0377ca9b336 Mon Sep 17 00:00:00 2001
From: Fraser Hewson <fraser.hewson@gmail.com>
Date: Sun, 24 Aug 2014 12:50:47 +0200
Subject: [PATCH 4/5] Add comments

---
 cachematrix.R | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index d5b101e25e2..e6e6d5184ba 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -6,14 +6,18 @@
 ## matrix as well as its inverce. Use this matrix with cacheSolve() 
 
 makeCacheMatrix <- function(m.orig = matrix()) {
-  m.result <- NULL
+  m.result <- NULL  #when created the result is not available
   set <- function(m.set) {
-    m.orig <<- m.set
-    m.result <<- NULL
+    m.orig <<- m.set #save the new matrix
+    m.result <<- NULL #clear the result
   }
-  get <- function() m.orig
-  setresult <- function(result) m.result <<- result
-  getresult <- function() m.result
+  
+  get <- function() m.orig #return the original
+  
+  setresult <- function(result) m.result <<- result #save a result matrix
+  
+  getresult <- function() m.result #return the result matrix
+  
   list(set = set, get = get,
        setresult = setresult,
        getresult = getresult)
@@ -25,16 +29,17 @@ makeCacheMatrix <- function(m.orig = matrix()) {
 ## cached result is used.
 
 cacheSolve <- function(x, ...) {
-  mcache <- NULL
-  mlist <- x
+  mcache <- NULL  #Cached matrix is initially null
   
-  m <- mlist$getresult()
+  m <- x$getresult() #Get the cached matrix and check if it exists
   if(!is.null(m)){
     message("Using cached data")
-    return(m)
+    return(m) #Use and return the cached matrix if found
   }
-  data <- mlist$get()
-  result <- solve(data, ...)
-  mlist$setresult(result)
-  result
+  
+  # Cached result was not found... Calculate
+  data <- x$get() #Get the initial matrix
+  result <- solve(data, ...) #Solve it
+  x$setresult(result) #Cache it
+  result #Return it
 }

From 6c032cbbd8fd6b2372dd6c0ccc7aec0e1b9f55cf Mon Sep 17 00:00:00 2001
From: Fraser Hewson <fraser.hewson@gmail.com>
Date: Sun, 24 Aug 2014 12:51:51 +0200
Subject: [PATCH 5/5] Assignment complete

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

diff --git a/cachematrix.R b/cachematrix.R
index e6e6d5184ba..5e40648eeeb 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -43,3 +43,5 @@ cacheSolve <- function(x, ...) {
   x$setresult(result) #Cache it
   result #Return it
 }
+
+#done