adding comments

Author: kim0

cachematrix.R

@@ -1,7 +1,13 @@
 ## Put comments here that give an overall description of what your
-## functions do
+## makeCacheMatrix create a special matrix that keeps its cache
+## cacheSolve knows to check cache first, otherwise do the expensive
+## computation
 
-## Write a short comment describing this function
+## makeCacheMatrix has the following functions
+## get: returns matrix
+## set: sets the matrix
+## setinv: sets the inverse
+## getinv: returns the inverse
 
 makeCacheMatrix <- function(x = matrix()) {
   inv <- NULL
@@ -18,7 +24,11 @@ makeCacheMatrix <- function(x = matrix()) {
 }
 
 
-## Write a short comment describing this function
+## cacheSolve has the following logic
+## It first checks if the matrix has a precomputed cache
+## if so, this is returned. If not, the "expensive" 
+## solve() function is called. The inversed matrix
+## is cached and returned
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'