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cachematrix.R
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## Matrix inversion is usually a costly computation and their 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). Your assignment is to write a pair of functions that cache the inverse
## of a matrix
## This function creates a special "matrix" object that can cache its inverse.
makeCacheMatrix <- function(x = matrix()) {
inv <- NULL
set <- function(y) {
x <<-y
inv <<- NULL
}
get <- function() x
getinv <- function() inv
setinv <- function(invmatrix) inv <<- invmatrix
list(set = set,
get = get,
getinv = getinv,
setinv = setinv)
}
## 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'
inv <- x$getinv()
if (!is.null(inv)) {
message("getting cached inverse")
return (inv)
}
m <- x$get()
inv <- solve(m, diag(dim(m)[1]))
x$setinv(inv)
inv
}