Implementation of inverse matrix caching

chriskopec · chriskopec · commit 78b020d35d89 · 2015-11-22T16:52:17.000-05:00
diff --git a/cachematrix.R b/cachematrix.R
@@ -1,15 +1,48 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Matrix inversion is usually a costly computation and there
+## may be some benefit to caching the inverse of a matrix rather
+## than compute it repeatedly. These functions compute and cache
+## the matrix inverse.
+##
+## These functions assume that the matrix supplied is invertible.
 
-## Write a short comment describing this function
 
+## makeCacheMatrix:
+## This function creates a special "matrix" with functions to
+## get, set, getsolve, and setsolve.
+##
+## 'x' is a matrix that is wrapped with additional functionality.
+##
+## Return a "special" matrix that is able to cache its inverse.
 makeCacheMatrix <- function(x = matrix()) {
-
+    m <- NULL
+    set <- function(y) {
+        x <<- y
+        m <<- NULL
+    }
+    get <- function() x
+    setsolve <- function(solve) m <<- solve
+    getsolve <- function() m
+    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.
+##
+## 'x' is a special "matrix" created by calling makeCacheMatrix
+##
+## Return the inverse of the special "matrix"
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+    m <- x$getsolve()
+    if(!is.null(m)) {
+        message("getting cached data")
+        return(m)
+    }
+    data <- x$get()
+    m <- solve(data, ...)
+    x$setsolve(m)
+    m
 }
