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Author: Oliver Ochs

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 creates a special "matrix" object that can cache its inverse
+## This special matrix has an internal cache "i" to do this.
+## There are three "methods" in this matrix:
+## set(value) to set the value
+## get() to retrive the value
+## setinverse(value) to fill the cache
+## getinverse() to get data from cache
 makeCacheMatrix <- function(x = matrix()) {
-
+  i <- NULL
+  set <- function(y) {
+    x <<- y
+    i <<- NULL
+  }
+  get <- function() x
+  setinverse<- function(i) i <<-i
+  getinverse <- function() i
+  list(set = set, get = get,
+       setinverse = setinverse,
+       getinverse = getinverse)
 }
 
-
-## Write a short comment describing this function
-
+## This function computes the inverse of the special "matrix" 
+## returned by makeCacheMatrix above. If the inverse has already been 
+## calculated (and the matrix has not changed), then cacheSolve retrieves
+## the inverse from the cache.
+## Otherwise the inverse function (solve) is used to invert the matrix.
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+  i <- x$getinverse()
+  if (!is.null(i)) {
+    message("found cached inverse matrix")
+    return(i)
+  } else {
+    i <- solve(x$get())
+    x$setinverse(i)
+    return(i)
+  }
 }