Implement matrix caching functions

srps · srps · commit 496432f8ad8a · 2020-09-22T19:26:55.000+01:00
Implements: makeCacheMatrix
                     cacheSolve
diff --git a/cachematrix.R b/cachematrix.R
@@ -1,15 +1,41 @@
-## Put comments here that give an overall description of what your
-## functions do
+## This function creates a list comprising of 4 functions:
 
-## Write a short comment describing this function
+## set <- sets matrix x in the makeCacheMatrix context 
+##        and clears the previous cached inverse (m)
 
-makeCacheMatrix <- function(x = matrix()) {
+## get <- gets matrix x in the makeCacheMatrix context 
 
-}
+## setinverse <- sets cached inverse m in the makeCacheMatrix context
+
+## getinverse <- cached inverse m in the makeCacheMatrix context 
 
+makeCacheMatrix <- function(x = matrix()) {
+  m <- NULL
+  set <- function(y) {
+    x <<- y
+    m <<- NULL
+  }
+  get <- function() x
+  setinverse <- function(solve) m <<- solve
+  getinverse <- function() m
+  list(set = set, get = get,
+       setinverse = setinverse,
+       getinverse = getinverse)
+}
 
-## Write a short comment describing this function
+## This function checks whether the inverse was already calculated and cached
+## If that's the case, just returns the cached value
+## Otherwise, calculates the inverse via solve function, caches and returns it
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'
+  m <- x$getinverse()
+  if (!is.null(m)) {
+    message("getting cached data")
+    return(m)
+  }
+  data <- x$get()
+  m <- solve(data, ...)
+  x$setinverse(m)
+  m
 }
