cachematrix.R

## This function creates a special "matrix" object that can cache its inverse
## It contains list of functions:
## * $set       : set the value of the matrix
## * $get       : get the value of the matrix
## * $setinverse: set the inverse of the matrix
## * $getinverse: get the inverse of the matrix

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


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