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My solutions to the week2 programming assignment

Author: OleTorp

cachematrix.R

@@ -1,15 +1,71 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
-
-makeCacheMatrix <- function(x = matrix()) {
-
-}
-
-
-## Write a short comment describing this function
-
-cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
-}
+## This pair of functions will provide facilities for constructing a global object for caching an invertible 
+## matrix and its inverse
+
+
+## MakeCacheMatrix, is a function that will construct a list-object providing the input matrix with variables and methods
+## for global setting and getting its value and inverse
+
+makeCacheMatrix <- function(x = matrix()) {
+        i <- NULL               # i is for holding the inverse
+        set <- function(y) {
+                x <<- y         # x is updated outside the current environment
+                i <<- NULL      # i is updated outside the current environment
+        }
+        get <- function() x
+        setinverse <- function(solve) i <<- solve
+        getinverse <- function() i
+        list(set = set, 
+             get = get,
+             setinverse = setinverse,
+             getinverse = getinverse)
+}
+
+
+## CacheSolve will access the global cache to check if an inverse of x has already been stored and return it. 
+## If not, it will compute the inverse and store it before returning the newly computed value. 
+
+cacheSolve <- function(x, ...) {
+        i <- x$getinverse()
+        if(!is.null(i)) {
+                message("getting cached data")
+                return(i)
+        }
+        data <- x$get()
+        i <- solve(data, ...)
+        x$setinverse(i)
+        i
+}
+
+## Simple Test:
+## ---------------------------------------------------------
+## > test <- matrix(c(-1,2,3,4,-1,6,7,8,-1), nrow=3, ncol=3)
+## >
+## > test
+## [,1] [,2] [,3]
+## [1,]   -1    4    7
+## [2,]    2   -1    8
+## [3,]    3    6   -1
+## >
+## > x <- makeCacheMatrix(test)
+## >
+## > cacheSolve(x)
+## [,1]       [,2]        [,3]
+## [1,] -0.18359375  0.1796875  0.15234375
+## [2,]  0.10156250 -0.0781250  0.08593750
+## [3,]  0.05859375  0.0703125 -0.02734375
+## >
+## > cacheSolve(x)
+## getting cached data
+## [,1]       [,2]        [,3]
+## [1,] -0.18359375  0.1796875  0.15234375
+## [2,]  0.10156250 -0.0781250  0.08593750
+## [3,]  0.05859375  0.0703125 -0.02734375
+## >
+## > x$set(test)
+## > cacheSolve(x)
+## [,1]       [,2]        [,3]
+## [1,] -0.18359375  0.1796875  0.15234375
+## [2,]  0.10156250 -0.0781250  0.08593750
+## [3,]  0.05859375  0.0703125 -0.02734375
+## > 
+