Assignment: Caching the Inverse of a Matrix

Matrix inversion is usually a costly computation and there may be some benefit to caching the inverse of a matrix rather than computing it repeatedly.

Your assignment is to write a pair of functions that cache the inverse of a matrix.

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 the inverse of the matrix
4. get the value of the inverse of the matrix

CODE

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)
}

END CODE

The following function calculates the inverse of the matrix created with the above function. However, it first checks to see if the inverse has already been calculated. If so, it gets the inverse from the cache and skips the computation. Otherwise, it calculates the inverse of the matrix and sets the value in the cache via the setinverse`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.

Computing the inverse of a square matrix can be done with the solvefunction in R. For example, if X is a square invertible matrix, then solve(X)` returns its inverse.

CODE

cacheSolve <- function(x, ...) {
        inv <- x$getinverse()
        if(!is.null(inv)) {
                message("getting cached data")
                return(inv)
        }

        data <- x$get()
        inv <- solve(data, ...)
        x$setinverse(inv)
        inv
}

END CODE

#The above code has been adapted from the code in Assignment 2.