Comments for the entire file. A usage section with short comments for each of the two functions: makeCacheMatrix and cacheSolve

Author: ccdatatraits

cachematrix.R

@@ -1,34 +1,60 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Couple of functions to optimize inversing matrixes as it could be fairly
+## computational work to find the inverse of a large matrix. Usage below:
+## 
+## [Inspired by Johanna Tikanmäki COMMUNITY TA usage for cachemean on
+## https://class.coursera.org/rprog-014/forum/thread?thread_id=105]
+##
+## cMatrix <- makeCacheMatrix(m) #first a cache aware matrix where 'm' is the 
+##                               #matrix you would like to use as input
+## cacheSolve(cMatrix) #calculate Inverse (solve) of the matrix
+## cacheSolve(cMatrix) #this will return the cached matrix inverse
+## cMatrix$set(new_m)  #cMatrix can be set to a new input matrix ('new_m')
+## cacheSolve(cMatrix) #calculate Inverse of new_m for the first time
+## cacheSolve(cMatrix) #this will return the cached inverse
+## cacheSolve(cMatrix) #same result as above; still cached
 
-## Write a short comment describing this function
 
-makeCacheMatrix <- function(x = matrix()) {
-    cachedMatrixInverse <- NULL
+## Create a cached aware matrix that that be reused with new matrixes as well
+
+makeCacheMatrix <- function(m = matrix()) {
+    cachedMatrixInverse <- NULL       #cached matrix inverse value if set
     set <- function(y) {
-        x <<- y
-        cachedMatrixInverse <<- NULL
+        m <<- y                       #set new value for raw matrix 'm' set
+                                      #at makeCacheMatrix function level using
+                                      #<<-
+        cachedMatrixInverse <<- NULL  #clear cached as 'm' has changed at the 
+                                      #parent frame of this function
     }
-    get <- function() x
+    get <- function() m               #get raw matrix 'm'
+                                      
+    #functions below: set & get cached matrix value for makeCacheMatrix's
+    #cacheMatrixInverse variable
     setMatrixInverse <- function(inv) cachedMatrixInverse <<- inv
     getMatrixInverse <- function() cachedMatrixInverse
+    
+    #return a list containing various functions that can be used to:
+    #get raw matrix 'm'
+    #set raw matrix that will clear matrix inverse as well
+    #getMatrixInverse to get cachedMatrixInverse
+    #setMatrixInverse to set cachedMatrixInverse
     list(set = set, get = get,
          setMatrixInverse = setMatrixInverse,
          getMatrixInverse = getMatrixInverse)
 }
 
 
-## Write a short comment describing this function
+## Solve (Inverse) and cache matrix. Has to be used as shown in the usage
+## section. 'x' has to be an object returned by makeCacheMatrix function
 
 cacheSolve <- function(x, ...) {
-    ## Return a matrix that is the inverse of 'x'
-    matrixInverse <- x$getMatrixInverse()
-    if(!is.null(matrixInverse)) {
-        message("found cached matrix inverse")
-        return(matrixInverse)
+    matrixInverse <- x$getMatrixInverse()       #try retrieving cached value
+    if(!is.null(matrixInverse)) {               #if we find the value
+        message("found cached matrix inverse")  #message we have cached value
+        return(matrixInverse)                   #return from this function
     }
-    matrix <- x$get()
-    calculatedMatrixInverse <- solve(matrix)
-    x$setMatrixInverse(calculatedMatrixInverse)
+    matrix <- x$get()                           #get actual matrix data
+    calculatedMatrixInverse <- solve(matrix)    #use solve from {base} package
+    x$setMatrixInverse(calculatedMatrixInverse) #set cached value for x
+    ## Return a matrix that is the inverse of 'x'
     calculatedMatrixInverse
 }