Peer asignmenet

nabilblk · nabilblk · commit f756c6956afe · 2014-04-26T21:31:49.000+01:00
diff --git a/cachematrix.R b/cachematrix.R
@@ -1,15 +1,60 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
+## Perform inversion of a matrix, cache the result, and assert the cache did
+## work by expecting a message in console ("getting cached data")
+##
+## Then verify the inversion was computed properly by multiplying the inverted
+## matrix by the original matrix. Expecting an identity matrix
 
+## ------------------------------------------------------------
+## Build a list of functions to perform the cached matrix
 makeCacheMatrix <- function(x = matrix()) {
+  # init cached result to null
+  m <- NULL
+  
+  # functions
+  setMatrix <- function(y) {
+    x <<- y
+    m <<- NULL
+  }
+  getMatrix <- function() x
+  setMatrixInverted <- function(matrixInverted) m <<- matrixInverted
+  getMatrixInverted <- function() m
+  
+  # list of functions
+  list(setMatrix = setMatrix, 
+       getMatrix = getMatrix, 
+       setMatrixInverted = setMatrixInverted, 
+       getMatrixInverted = getMatrixInverted)
+}
+
+## ------------------------------------------------------------
+## Search the cache or resolve and store if the result is not in cache
+cacheSolve <- function(x, ...) {
+  m <- x$getMatrixInverted()
+  if(!is.null(m)) {
+    message("getting data From Cache")
+    return(m)
+  }
+  message("Data not found in the cache . computing ...")
+  
+  data <- x$getMatrix()
+  m <- inverse(data, ...)
+  x$setMatrixInverted(m)
+  m
+}
 
+## ------------------------------------------------------------
+## Doing the actual matrix inversion
+inverse <- function(x){
+  solve(x) # ginv or solve
 }
 
+## Apply calculation
+v <- cbind(c(0.5, 0.3), c(0.4, 0.9))
+cv <- makeCacheMatrix(v)
+im <- cacheSolve(cv)
+
+## Verify results
+im <- cacheSolve(cv)
+print(im %*% v)
 
-## Write a short comment describing this function
 
-cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
-}
