Adds the commented solution of the assignment

I.e. cached version of solving/inverting a matrix

Author: Sebastian Stabinger

cachematrix.R

@@ -1,15 +1,37 @@
 ## Put comments here that give an overall description of what your
 ## functions do
 
-## Write a short comment describing this function
-
+## This function returns a list of functions used to manage the matrix
+## content and the memorized inverse of the matrix
 makeCacheMatrix <- function(x = matrix()) {
-
+    m <- NULL               # Contains the memorized inverse matrix
+    set <- function(y){     # Reassign matrix
+        x <<- y
+        m <<- NULL           # Memorized value is not valid anymore
+    }
+    get <- function() x     # Return matrix content
+    setinv <- function(inv) m <<- inv  # Set a new memorized value
+    getinv <- function() m            # Return memorized inverse
+    list(set = set,
+         get = get,
+         setinv = setinv,
+         getinv = getinv)             # Provides the interface for the functions
 }
 
-
-## Write a short comment describing this function
-
+## Returns the inverse of the matrix x (created with makeCacheMatrix).
+## If the inverse has already been calculated before for the same
+## matrix, the computation will not be repeated, but a memorized
+## version of the inverse will be returned
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    m <- x$getinv()    # Get currently memorized value
+    ## If a memorized value exists, return it
+    if(!is.null(m)){   
+        message("returning memorized data")
+        return(m)
+    }
+    ## If no memorized value exists
+    data <- x$get()        # Get current matrix represented by x
+    m <- solve(data, ...)  # Get the inverse
+    x$setinv(m)            # Memorize this inverse
+    m                      # Return the inverse
 }