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cachematrix.R
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58 lines (43 loc) · 2.23 KB
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## We create functions that are able to cache time-consuming computations: Caching the inverse of a matrix
## The function makeVector creates a special "vector", which is really a list containing a function to
## set the value of the vector
## get the value of the vector
## set the value of the inverse
## get the value of the inverse
makeCacheMatrix <- function(x = matrix()) {
invX <- NULL ## init the inverse of x
set <- function(y) { ## set the matrix
x <<- y
invX <<- NULL
}
get <- function() x ## get the matrix
setInverse <- function(inverse) invX <<- inverse ## set the inverse matrix
getInverse <- function() invX ## get the inverse matrix
list(set = set, get = get, ## return
setInverse = setInverse,
getInverse = getInverse)
}
## The following function calculates the inverse of the special "vector" 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 data and sets the value of the inverse in the cache via the setInverse function.
cacheSolve <- function(x, ...) {
## Return a matrix that is the inverse of 'x'
invX <- x$getInverse() ## try to get from cache
if(!is.null(invX)) { ## if in cache...
message("getting cached data")
return(invX)
}
## if not in cache
data <- x$get()
invX <- solve(data, ...) ## get the inverse
x$setInverse(invX)
invX ## return
}
## TEST
# m1 <- matrix( c(1, 2, 3, 4), nrow=2, ncol=2)
# m1
# cache <- makeCacheMatrix(m1)
# cache <- makeCacheMatrix(m1) ## gets from teh cache now!
# out <- cacheSolve(m1)
# out