homework

Author: rrbaker

cachematrix.R

@@ -4,12 +4,42 @@
 ## Write a short comment describing this function
 
 makeCacheMatrix <- function(x = matrix()) {
+    inv <- NULL
 
+    set <- function(y){
+        x <<- y
+        inv <<- NULL
+    }
+
+    get <- function() x
+    setinv <- function(solve) inv <<- solve
+    getinv <- function() inv
+    list(set = set, get = get, setinv = setinv, getinv = getinv)
 }
 
 
-## Write a short comment describing this function
+# This function delivers the inverted matrix from makeCacheMatrix,
+# first looking for a cached version and if not there
+# computing and returning the inversion.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    # Return an inverted matrix of the passed matrix.
+    inv <- x$getinv()
+
+    # Look for a cached version
+    if(!is.null(inv)) {
+        message("Aw yiss, a cached version.")
+        return(inv)
+    }
+    
+    # Otherwise invert the matrix.
+    data <- x$get()
+    inv <- solve(data, ...)
+    x$setinv(inv)
+    inv
 }
+
+# Test it out
+test <- makeCacheMatrix()
+test$set(matrix(c(1:4),2,2))
+cacheSolve(test)