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cachematrix.R
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cachematrix.R
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## The functions makeCacheMatrix and cacheSolve are used to cache computing of
## matrix inverse. The first time the inverse is requested, builtin function solve()
## is used to get the inverse and the value is stored in a cache. In the following
## requests the value of inverse is retrieved from the cache.
## This function takes as an argument a matrix and returns a list of
## four functions: get(), set(), setinverse(), getinverse().
## Its output is passed as an argument to the cacheSolve function.
makeCacheMatrix <- function(x = matrix()) {
inv <- NULL
set <- function(y) {
x <<- y
inv <<- NULL
}
get <- function() x
setinverse <- function(solve) inv <<- solve
getinverse <- function() inv
list(set = set, get = get,
setinverse = setinverse,
getinverse = getinverse)
}
## This function checks if the value of the inverse of the matrix has been already
## computed. If it has, it returns it, otherwise it uses solve() to compute
## the inverse and then stores it for the future requests.
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
}
#Sample test
# a<- makeCacheMatrix(matrix(c(1, 1, 1, 3, 4, 3, 3, 3, 4),3))
# b <- cacheSolve(a)