Assignment: Caching the Inverse of a Matrix

Author: jairom

cachematrix.R

@@ -3,13 +3,66 @@
 
 ## Write a short comment describing this function
 
-makeCacheMatrix <- function(x = matrix()) {
+### Jairo's comments
+
+### Matrix inversion is usually a costly computation, if there is need to compute many times 
+### the same, store the result of inverse of a matrix in the cache and return the result 
+### when need is more efficient than compute it repeatedly.
+
+### following two functions are used to cache the inverse of a matrix.
+
+### makeCacheMatrix creates a matrix object that can cache its inverse
 
+makeCacheMatrix <- function(x = matrix()) {
+    ## Initialize the inverse property
+    inv <- NULL
+    
+    ### set the value of the matrix
+    set <- function(y) {
+        x <<- y
+        inv <<- NULL
+    }
+    
+    ### get the value of the matrix    
+    get <- function() x
+    
+    ### set the value of inverse of the matrix    
+    setinverse <- function(inverse) inv <<- inverse
+    
+    ### get the value of inverse of the matrix    
+    getinverse <- function() inv
+    
+    ### Return list of the methods
+    list(set=set, get=get, setinverse=setinverse, getinverse=getinverse)
 }
 
 
 ## Write a short comment describing this function
 
+### Jairo's comments
+
+### This function returns the inverse of the matrix. 
+### 1. It first checks if the inverse has already been computed. If exist, it returns the result 
+###    and skips the computation. 
+### 2. If not, it computes the inverse, stores the value in the cache via setinverse function.
+
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    ## Return a matrix that is the inverse of 'x'
+    inv <- x$getinverse()
+    
+    ## If the inverse already set, return it
+    if(!is.null(inv)) {
+        message("getting cached data.")
+        return(inv)
+    }
+    
+    ## Get the matrix from our object
+    data <- x$get()
+    
+    ## Compute the inverse using matrix multiplication
+    inv <- solve(data)
+    
+    ## Set the value to the object and return it
+    x$setinverse(inv)
+    inv
 }