done cachematrix

Author: Andre Casimiro

cachematrix.R

@@ -1,15 +1,38 @@
-## Put comments here that give an overall description of what your
-## functions do
+# This file implements two functions: makeCacheMatrix and cacheSolve.
+# Together they provide a way to construct a matrix object that caches
+# its inverse computation, provinding faster access to it.
 
-## Write a short comment describing this function
 
+# makeCacheMatrix creates an object that represents a matrix that the
+# inverse operation is cached for faster computations.
 makeCacheMatrix <- function(x = matrix()) {
-
+    x_inv <- NULL
+    set <- function(x_new) {
+        x <<- x_new
+        x_inv <<- NULL
+    }
+    get <- function() {
+        x
+    }
+    set_inverse <- function(x_inv_new) {
+        x_inv <<- x_inv_new
+    }
+    get_inverse <- function() {
+        x_inv
+    }
+    list(set = set, get = get, set_inverse = set_inverse, get_inverse = get_inverse)
 }
 
-
-## Write a short comment describing this function
-
+# cacheSolve solves the inverse of the matrix x and caches its results
+# so that later requests are not calculated again
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    xi <- x$get_inverse()
+    if(!is.null(xi)) {
+        message("getting cached inverse matrix")
+        return(xi)
+    }
+    x_data <- x$get()
+    xi <- solve(x_data)
+    x$set_inverse(xi)
+    xi
 }