Programming Assignment 2: Lexical Scoping

Author: Gehad Wahgdy

cachematrix.R

@@ -1,15 +1,39 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
+## Matrix inversion is usually a costly computation and there may be some benefit to caching the inverse of
+## a matrix rather than compute it repeatedly. Below are a pair of functions that cache the inverse of a matrix.
 
+## makeCacheMatrix: 
+## This function creates a special "matrix" object that can cache its inverse.
+##
 makeCacheMatrix <- function(x = matrix()) {
-
+  invMatrix <- NULL
+  set <- function(y) {
+    x <<- y
+    invMatrix <<- NULL
+  }
+  get <- function() x
+  setInverse <- function(inv) invMatrix <<- inv
+  getInverse <- function() invMatrix
+  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.
+## If the inverse has already been calculated (and the matrix has not changed), 
+## then cacheSolve should retrieve the inverse from the cache.
+##
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+  invMatrix <- x$getInverse()
+  if(!is.null(invMatrix)) {
+    message("getting cached matrix")
+    return(invMatrix)
+  }
+  m <- x$get()
+  ## Return a matrix that is the inverse of 'm'
+  invMatrix <- solve(m, ...)
+  x$setInverse(invMatrix)
+  invMatrix
 }