makeCacheMatrix and cacheSolve methods

Author: cstuss-timeinc

cachematrix.R

@@ -1,15 +1,40 @@
-## Put comments here that give an overall description of what your
-## functions do
+## A pair of functions that cache the inverse of a matrix
 
-## Write a short comment describing this function
+## makeCacheMatrix: This function creates a special "matrix" object that can cache its inverse (solve).
+# It creates a special "matrix", which is really a list containing a function to:
+# set the value of the matrix
+# get the value of the matrix
+# set the value of the solve
+# get the value of the solve
 
 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
-
+## cacheSolve: 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 cacheSolve should retrieve the inverse from the cache.
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    # Return a matrix that is the inverse of 'x'
+    s <- x$getsolve()
+    if(!is.null(s)) {
+        message("getting cached solve")
+        return(s)
+    }
+    data <- x$get()
+    # Computing the inverse of a square matrix can be done with solve(x)
+    s <- solve(data, ...)
+    x$setsolve(s)
+    s
 }