updated cachematrix.R with the updated methods and functionality.

Author: bambock

cachematrix.R

@@ -1,40 +1,59 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Ethan Bambock
+## R-Programming - Assignment 2
+## 2015/01/22
 
-## Write a short comment describing this function
+## This script provides a reuseable method for setting and getting a matrix and it's inverse values.  
+## Additionally, the cached data can be retained using a global variable ("i") that doesn't have to
+## recalculated when the function getinverse() is called.  This technique allows an application or process
+## to run more efficiently without having to process unnecessary work.
 
-makeCacheMatrix <- function(x = matrix()) {
+## This function is used to define a special 'matrix' object with a series of functions that can be 
+## called to obtain or set a matrix value and cache it's inverse.  
 
+makeCacheMatrix <- function(mx = matrix()) {
+    
+    message("makecachematrix: initializing matrix object and functions")
+    # initializing the inverse matrix object to NULL
+    i <- NULL
+    
+    # set() is used to store matrix passed as an argument or sets a default
+    set <- function(y) {
+        mx <<- y
+        i <<- NULL
+    }
+    
+    # get() returns the value of the matrix that has been stored
+    get <- function() mx
+    
+    # setinverse() is used to store the inverse matrix 'globally' for the currently set matrix
+    setinverse <- function(inverse) i <<- inverse
+    
+    # getinverse() returns the inverse matrix that is currently stored 'globally'
+    getinverse <- function() i
+    
+    # last command evaluated and returns a list of the defined functions
+    list(set = set, get = get, setinverse = setinverse, getinverse = getinverse)
 }
 
 
-## Write a short comment describing this function
+## This function is used to verify if a matrix inverse has been set and use the data stored.  If
+## the inverse matrix returned from getmatrix() above is NULL, the data is obtained and the inverse
+## is calculated with the solve() function, stored, and returned.
 
-cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
-}
-makeVector <- function(x = numeric()) {
-  m <- NULL
-  set <- function(y) {
-    x <<- y
-    m <<- NULL
-  }
-  get <- function() x
-  setmean <- function(mean) m <<- mean
-  getmean <- function() m
-  list(set = set, get = get,
-       setmean = setmean,
-       getmean = getmean)
-}
-
-cachemean <- function(x, ...) {
-  m <- x$getmean()
-  if(!is.null(m)) {
-    message("getting cached data")
-    return(m)
-  }
-  data <- x$get()
-  m <- mean(data, ...)
-  x$setmean(m)
-  m
-}
+cacheSolve <- function(mx, ...) {
+    ## Return a matrix that is the inverse of 'mx'
+    i <- mx$getinverse()
+    
+    # if the data returned is not null, return the value retrieved from getinverse()
+    if(!is.null(i)) {
+        message("cachesolve: getting cached inverse matrix")
+        return(i)
+    }
+    
+    # otherwise cache the new data and return the value
+    message("cachesolve: setting cached inverse matrix")
+    data <- mx$get()
+    i <- solve(data, ...)
+    mx$setinverse(i)
+    i
+}