cachematrix.R

## Andrew Freisthler
## Coursera R Programming - September 2014

## The two functions below, makeCacheMatrix and cacheSolve work together
##   to lesson the impact of the computationally intensive operation of
##   computing the inverse of a matrix if it has already been computed.
##
## Example Usage (second call to cacheSolve would not require recalculating):
##   source("./cachematrix.R")
##   m <- matrix(rnorm(100),10,10)
##   cm <- makeCacheMatrix(m)
##   cacheSolve(cm)
##   cacheSolve(cm)
##

## makeCacheMatrix creates a special 'matrix', which is really a list containing methods:
##  1) set the value of the matrix
##  2) get the value of the matrix
##  3) set the value of the solve
##  4) get the value of the solve

makeCacheMatrix <- function(x = matrix()) {
    cachedSolve <- NULL
    
    set <- function(y) {
        x <<- y
        cachedSolve <<- NULL
    }
    
    get <- function() {
        x
    }
    
    setSolve <- function(solve) {
        cachedSolve <<- solve
    }
    
    getSolve <- function() {
        cachedSolve
    }
    
    list(set = set, get = get, setSolve = setSolve, getSolve = getSolve)
}


## cacheSolve returns the output of solve if it has already been calculated, otherwise it 
##   calculates and then stores it.

cacheSolve <- function(x, ...) {
    solveFromCache = x$getSolve()
    if(!is.null(solveFromCache)) {
        message("getting cached data")
        return(solveFromCache)
    }
    
    data <- x$get()
    solveToCache <- solve(data, ...)
    x$setSolve(solveToCache)
    solveToCache   
}