From 0c2f838c1f37203e22b47a7ce8f982397ef79325 Mon Sep 17 00:00:00 2001
From: SirAlf <sir_alf@rocketmail.com>
Date: Sun, 13 Apr 2014 23:16:57 +0800
Subject: [PATCH 1/3] my commit to peer assessment assignment

---
 cachematrix.R | 40 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..a6244985609 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,45 @@
-## Put comments here that give an overall description of what your
-## functions do
+## This function caches the inverse of a matrix
+## 
 
-## Write a short comment describing this function
+## The makeCacheMatrix creates a special "matrix" object that can cache
+##   its Inverse 
 
 makeCacheMatrix <- function(x = matrix()) {
+	inv <- NULL
+	set <- function(y) {
+                x <<- y
+                inv <<- NULL
+	}
+      
+	get <- function() x
+      setinv <- function(solve) inv <<- solve
+      getinv <- function() inv
+   
+	list(set = set, get = get,
+             setinv = setinv,
+             getinv = getinv)
 
 }
 
+## The cacheSolve function computes the inverse of the 
+##    special "matrix" returned by makeCacheMatrix if it 
+##    has not been cached.
 
-## Write a short comment describing this function
+## If the inverse has been cached, it will return the cached value
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+      ## Return a matrix that is the inverse of 'x'
+ 	
+	inv <- x$getinv()
+      
+	if(!is.null(inv)) {
+                message("getting cached data")
+                return(inv)
+      }
+      
+	data <- x$get()
+      inv <- solve(data, ...)
+      x$setinv(inv)
+      inv
+
 }

From e5115478224d68b8df8019ab7223fec49b21971c Mon Sep 17 00:00:00 2001
From: SirAlf <sir_alf@rocketmail.com>
Date: Fri, 16 Jan 2015 10:16:44 +0800
Subject: [PATCH 2/3] recommit updated ProgrAssgnmt2

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

diff --git a/cachematrix.R b/cachematrix.R
index a6244985609..af9ef620cf7 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,4 +1,4 @@
-## This function caches the inverse of a matrix
+## This function  caches  the inverse of a matrix
 ## 
 
 ## The makeCacheMatrix creates a special "matrix" object that can cache

From 57b2efa7705973f53cbefc7e43a587ec5969ea6d Mon Sep 17 00:00:00 2001
From: SirAlf <SirAlf@users.noreply.github.com>
Date: Mon, 2 Oct 2017 17:21:36 +0800
Subject: [PATCH 3/3] RProgPA2Date2017Oct

I retook the course after a couple of years, but this time I am aiming for the certificate
---
 .Rhistory     | 0
 cachematrix.R | 3 ++-
 2 files changed, 2 insertions(+), 1 deletion(-)
 create mode 100644 .Rhistory

diff --git a/.Rhistory b/.Rhistory
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/cachematrix.R b/cachematrix.R
index af9ef620cf7..bcebb410a0a 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -15,7 +15,8 @@ makeCacheMatrix <- function(x = matrix()) {
       setinv <- function(solve) inv <<- solve
       getinv <- function() inv
    
-	list(set = set, get = get,
+	list(set = set, 
+	           get = get,
              setinv = setinv,
              getinv = getinv)