updated cachematrix.R considering my solution to the assignment.

rduran · rduran · commit 573bc4fec29b · 2016-03-28T22:51:16.000-03:00
diff --git a/cachematrix.R b/cachematrix.R
@@ -1,15 +1,61 @@
-## Put comments here that give an overall description of what your
-## functions do
+## JHDS Certification - R Programming
+##
+## Rodrigo Duran :: https://github.com/rduran/ProgrammingAssignment2
+##
+## Assignment: Caching the Inverse of a Matrix
+##
+## Computing the inverse of a square matrix can be done with the solve function
+## in R. For example, if X is a square invertible matrix, then solve(X) returns
+## its inverse.
+##
+## For this assignment, assume that the matrix supplied is always invertible.
 
-## Write a short comment describing this function
 
+##
+## makeCacheMatrix: This function creates a special "matrix" object that can cache
+##                  its inverse
+##
 makeCacheMatrix <- function(x = matrix()) {
-
+        cached <<- NULL
+        
+        ## makes sure that cached element is empty
+        set <- function(y) {
+                x <<- y
+                cached <<- NULL
+        }
+        
+        ## Retreives the original matrix
+        get <- function() x
+        
+        ## Caches the inverse
+        setInverse <- function(x) cached <<- x
+        
+        ## Retreives the cached value
+        getInverse <- function() cached
+        
+        ## Expose the API for caching
+        list( set = set, get = get, setInverse = setInverse, 
+              getInverse = getInverse)
 }
 
-
-## Write a short comment describing this function
-
+##
+## cacheSolve: 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 the
+##             cachesolve should retrieve the inverse from the cache.
+##
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+        ## Retrieves the cached inverse matrix
+        inv_m <- x$getInverse()
+        if( !is.null(inv_m) ) {
+                message("getting cached data")
+                return(inv_m)
+        }
+        
+        ## If the cached inverse matrix is null, proceed with calculation
+        m <- x$get()            # Retrieves the orignal matrix
+        inv_m <- solve(m, ...)  # Calculates the inverse matrix
+        x$setInverse(inv_m)     # Caches the inverse matrix
+        
+        inv_m
 }
