Added the code to get/set the matrices and solve (inverse) them.

Author: dwscoursera

cachematrix.R

@@ -1,15 +1,57 @@
-## Put comments here that give an overall description of what your
-## functions do
+## These functions cache the inverse of a matrix. makeMatrixCache
+## creates an object that will get a cached matrix or store a 
+## matrix in the cache.
+## cacheSolve is the way to interact with matrix cache.
 
-## Write a short comment describing this function
+## Example usage: 
+## c=rbind(c(1, -1/4), c(-1/4, 1))  
+## > c=rbind(c(1, -1/4), c(-1/4, 1))  
+## > c
+## > d<-makeCacheMatrix(c)
+
+## [,1]  [,2]
+## [1,]  1.00 -0.25
+## [2,] -0.25  1.00
+
+## > cacheSolve(d)
+## [,1]      [,2]
+## [1,] 1.0666667 0.2666667
+## [2,] 0.2666667 1.0666667
+
+
+## This function creates a special "matrix" object
+## that can cache its inverse.
 
 makeCacheMatrix <- function(x = matrix()) {
+        m <- NULL
+        set <- function(y) {
+                x <<- y
+                m <<- NULL
+        }
+        get <- function() x
+        setinv <- function(mean) m <<- mean
+        getinv <- function() m
+        list(set = set, get = get,
+             setinv = setinv,
+             getinv = getinv)
 
 }
 
 
-## Write a short comment describing this function
+## 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
+## `cacheSolve` should retrieve the inverse from the cache.
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'
+        m <- x$getinv()
+        if(!is.null(m)) {
+                message("getting cached data")
+                return(m)
+        }
+        data <- x$get()
+        m <- solve(data, ...)
+        x$setinv(m)
+        m
 }