From 4273874b1ef55c626746bd30f237d1b34e29b04d Mon Sep 17 00:00:00 2001
From: knokname <wliou@hawaii.edu>
Date: Thu, 24 Apr 2014 22:26:43 -1000
Subject: [PATCH] adding R Programming peer assignment

---
 .Rhistory     | 36 ++++++++++++++++++++++++++++++++++++
 cachematrix.R | 30 +++++++++++++++++++++++++-----
 2 files changed, 61 insertions(+), 5 deletions(-)
 create mode 100644 .Rhistory

diff --git a/.Rhistory b/.Rhistory
new file mode 100644
index 00000000000..f9a795d1fa8
--- /dev/null
+++ b/.Rhistory
@@ -0,0 +1,36 @@
+makeCacheMatrix <- function(x = matrix()) {
+m <- NULL
+set <- function(y){
+x <<- y
+m <<- NULL
+}
+get <- function() x
+setinverse <- function(solve) m <<- solve
+getinverse <- function() m
+list(set = set, get = get,
+setinverse = setinverse,
+getinverse = getinverse)
+}
+a <- makeCacheMAtrix(matrix(1:4,2))
+a <- makeCacheMatrix(matrix(1:4,2))
+a$get()
+a$getinverse()
+cacheSolve <- function(x, ...) {
+## Return a matrix that is the inverse of 'x'
+m <- x$getinverse()
+if(!is.null(m)){
+message("getting cached data")
+return(m)
+}
+data <- x$get()
+m <- solve(data,...)  ## returns inverse of matrix data <- x
+x$setinverse(m)
+m
+}
+a$set
+a$set(matrix(5:8,2))
+a$get()
+cachesolve(a)
+cacheSolve(a)
+cacheSolve(a)
+a$getinverse()
diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..731dde81a71 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,35 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Cache matrix inversion and allows look up in cache if
+## matrix was previously inverted
 
-## Write a short comment describing this function
+## This function creates a special "matrix" object that can cache its inverse
 
 makeCacheMatrix <- function(x = matrix()) {
-
+  m <- NULL
+  set <- function(y){
+    x <<- y
+    m <<- NULL
+  }
+  get <- function() x
+  setinverse <- function(solve) m <<- solve
+  getinverse <- function() m
+  list(set = set, get = get,
+       setinverse = setinverse,
+       getinverse = getinverse)
 }
 
 
-## Write a short comment describing this function
+## This function computes the special "matrix" returned in makeCacheMatrix;
+## if the inverse has already been calculated, this function retrieves from the cache
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'
+  m <- x$getinverse()
+  if(!is.null(m)){
+      message("getting cached data")
+      return(m)
+  }
+  data <- x$get()
+  m <- solve(data,...)  ## returns inverse of matrix data <- x
+  x$setinverse(m)
+  m
 }