programming assignment2

cachematrix.R

@@ -1,15 +1,32 @@
-## Put comments here that give an overall description of what your
-## functions do
-
-## Write a short comment describing this function
-
+# makeCacheMatrix creates 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 inverse of the matrix
+#4. get the value of inverse of the 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
-
+# The following function returns the inverse of the matrix. It first checks if
+# the inverse has already been computed. If so, it gets the result and skips the
+# computation. If not, it computes the inverse, sets the value in the cache via
+# setinverse function.
+# This function assumes that the matrix is always invertible.
 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
+}