Submission of assignment rdpeng#2.

keep94 · keep94 · commit 0b7fb15fa0a1 · 2022-07-03T14:46:51.000-07:00
diff --git a/cachematrix.R b/cachematrix.R
@@ -1,15 +1,35 @@
-## Put comments here that give an overall description of what your
-## functions do
+## These functions manipulate a special type of matrix which caches its
+## inverse.
 
-## Write a short comment describing this function
+## makeCacheMatrix creates a new "cache matrix" from a regular matrix.
 
 makeCacheMatrix <- function(x = matrix()) {
-
+        inv <- NULL
+        set <- function(y) {
+                x <<- y
+                inv <<- NULL
+        }
+        get <- function() x
+        setinverse <- function(inverse) inv <<- inverse
+        getinverse <- function() inv
+        list(set = set,
+             get = get,
+             setinverse = setinverse,
+             getinverse = getinverse)
 }
 
 
-## Write a short comment describing this function
+## cacheSolve returns the inverse of x where x is a "cache matrix"
 
 cacheSolve <- function(x, ...) {
         ## Return a matrix that is the inverse of 'x'
+        inv <- x$getinverse()
+        if (!is.null(inv)) {
+                message("getting cached data")
+                return(inv)
+        }
+        data <- x$get()
+        inv <- solve(data, ...)
+        x$setinverse(inv)
+        inv
 }
