cachematrix.R

# Thoses functions have the purpose of calculating and storing an inversed matrix to the cache :

# makeCacheMatrix is a function that creates a special "matrix" object that can cache its inverse:

makeCacheMatrix <- function(x = matrix()) {
  # create a matrix object x and some associated sub-functions/methods
  
  # define the cache m
  m <- NULL # initialize m 
  set <- function(y) { # set the value of the matrix
    x <<- y 
    m <<- NULL # re-initialize m in the parent environment to null
  }
  get <- function() x # get the value of the matrix
  setinverse <- function(inverse) m <<- inverse # set the cache m equal
  # to the inverse of the matrix x
  getinverse <- function() m # return the cached inverse of x
  list(set = set, get = get,
       setinverse = setinverse,
       getinverse = getinverse)
}


# 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 cacheSolve 
#should retrieve the inverse from the cache.

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