assignment solution

Author: Andrei Holub

cachematrix.R

@@ -1,15 +1,41 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
+## Matrix inversion is usually a costly computation and their may be some
+## benefit to caching the inverse of a matrix rather than compute it repeatedly.
+## Folowing pair of functions that cache the inverse of a matrix.
 
+## The first function, makeCacheMatrix creates a special "matrix", which 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 inversed matrix
+## 4. get the value of the inversed matrix
 makeCacheMatrix <- function(x = matrix()) {
-
+    s <- NULL
+    set <- function(y) {
+        x <<- y
+        s <<- NULL
+    }
+    get <- function() x
+    setsolve <- function(solve) s <<- solve
+    getsolve <- function() s
+    list(set = set, get = get,
+         setsolve = setsolve,
+         getsolve = getsolve)
 }
 
-
-## Write a short comment describing this function
-
+## The following function calculates the inversed matrix of the special "matix"
+## created with the above function. However, it first checks to see if the
+## inversed matrix has already been calculated. If so, it gets the inversed
+## matrix from the cache and skips the computation. Otherwise, it calculates the
+## inversed matrix of the data and sets the value of the inversion in the cache
+## via the setsolve function.
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    s <- x$getsolve()
+    if(!is.null(s)) {
+        message("getting cached data")
+        return(s)
+    }
+    data <- x$get()
+    s <- solve(data, ...)
+    x$setsolve(s)
+    s
 }

test.R

@@ -0,0 +1,5 @@
+source("cachematrix.R")
+mat8 <- matrix(1:6, 2)
+m <- makeCacheMatrix(mat8[, 2:3])
+cacheSolve(m)
+cacheSolve(m)