cachematrix.R

## This function caches the inverse of a matrix

## This function creates a special "matrix" object that can cache its inverse. 
## It is really a list containing a function to:
##      1. set the value of the matrix
##      2. get the value of the matrix
##      3. set the value of the inverse
##      4. get the value of the inverse

makeCacheMatrix <- function(x = matrix()) {
        m <- NULL
        set <- function(y){
                x <<- y
                m <<- NULL
        }
        get <- function() x
        setinv <- function(inverse) m <<- inverse
        getinv <- function() m
        list(set = set, get = get, setinv = setinv, getinv = getinv)
}

## 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 the 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
}