cachematrix.R

## This code is for programming Assignment 2 for coursera
## R programming course rprog-004
## 

## makeCacheMatrix: This function creates a special "matrix" object
## that can cache its inverse

makeCacheMatrix <- function(x = matrix()) {
        i <- NULL
        get <- function() x
        setinv <- function(inv) i <<- inv
        getinv <- function() i
        list(get = get,
             setinv = setinv,
             getinv = getinv)

}


## 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 the cachesolve should
## retrieve the inverse from the cache

cacheSolve <- function(x, ...) {
        ## Return a matrix that is the inverse of 'x'
        i <- x$getinv()
        if(!is.null(i)) {
	## if we have a cached inverse then return it
                message("getting cached data")
                return(i)
        }
	## else compute the inverse
        data <- x$get()
        i <- solve(data, ...)

	## and set it before returning it
        x$setinv(i)
        i

}