cachematrix.R

## Caching the inverse of a matrix

## The function makeCacheMatrix creates a special 
## "matrix" object that can cache its inverse.

makeCacheMatrix <- function(x = matrix()) {
  i <- NULL
  set <- function(y) {
    x <<- y
    i <<- NULL
  }
  get <- function() x
  setinverse <- function(inverse) i <<- inverse
  getinverse <- function() i
  list(set = set, get = get,
       setinverse = setinverse,
       getinverse = getinverse)
}


## The function cacheSolve 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'
  
  i <- x$getinverse()
  if(!is.null(i)) {
    message("getting cached data")
    return(i)
  }
  data <- x$get()
  i <- solve(data, ...)
  x$setinverse(i)
  i
}