cachematrix.R

## Some usefull functions to be more efficient to calculate a matrix inverse
## by using a cache 

## 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
  setinverse <- function(inverse) m <<- inverse
  getinverse <- function() m
  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 retrieves the inverse from the cache.

cacheSolve <- function(x, ...) {
  m <- x$getinverse()
  if(!is.null(m)) {
    message("get cached value")
    return(m)
  }
  data <- x$get()
  m <- solve(data, ...)
  x$setinverse(m)
  m
}