cachematrix.R

## Set of functions calculate and cache the inverse of a matrix.

## makeCacheMatrix: creates a "matrix" object that can cache its inverse.

makeCacheMatrix <- function(x = matrix()) {

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

}


## 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'
  if(!is.recursive(x)){
    message("argument is not recursive")
    return(x)
  }
  
  inv <- x$getinv()
  if(!is.null(inv)) {
    message("getting cached matrix")
    return(inv)
  }
  m <- x$get()
  m <- solve(m, ...)
  x$setinv(m)
  m
  
}