Implemented cache matrix assignment

Oleg Atamanenko · Oleg Atamanenko · commit 8055cfd27ff0 · 2016-01-25T00:36:32.000-05:00
diff --git a/cachematrix.R b/cachematrix.R
@@ -1,15 +1,37 @@
-## 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 there may be some
+## benefit to caching the inverse of a matrix rather than compute it repeatedly
+## (there are also alternatives to matrix inversion that we will not discuss
+## here).
 
+## Create a special "matrix" object that can 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
-
+## Compute 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.
+## Assumption: provided matrix is invertible.
 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
 }
