Description
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 compute it repeatedly.
Below are a pair of functions that are used to create a special object that
stores a matrix and caches its inverse.
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
setInverse <- function(inverse) inv <<- inverse
getInverse <- function() inv
list(set = set,
get = get,
setInverse = setInverse,
getInverse = getInverse)
}
This function computes the inverse of the special "matrix" created by
makeCacheMatrix above. If the inverse has already been calculated (and the
matrix has not changed), then it should retrieve the inverse from the cache.
cacheSolve <- function(x, ...) {
## Return a matrix that is the inverse of 'x'
inv <- x$getInverse()
if (!is.null(inv)) {
message("getting cached data")
return(inv)
}
mat <- x$get()
inv <- solve(mat, ...)
x$setInverse(inv)
inv
}
source("ProgrammingAssignment2/cachematrix.R")
my_matrix <- makeCacheMatrix(matrix(1:4, 2, 2))
my_matrix$get()
[,1] [,2]
[1,] 1 3
[2,] 2 4
my_matrix$getInverse()
NULL
cacheSolve(my_matrix)
[,1] [,2]
[1,] -2 1.5
[2,] 1 -0.5
cacheSolve(my_matrix)
getting cached data
[,1] [,2]
[1,] -2 1.5
[2,] 1 -0.5
my_matrix$getInverse()
[,1] [,2]
[1,] -2 1.5
[2,] 1 -0.5
my_matrix$set(matrix(c(2, 2, 1, 4), 2, 2))
my_matrix$get()
[,1] [,2]
[1,] 2 1
[2,] 2 4
my_matrix$getInverse()
NULL
cacheSolve(my_matrix)
[,1] [,2]
[1,] 0.6666667 -0.1666667
[2,] -0.3333333 0.3333333
cacheSolve(my_matrix)
getting cached data
[,1] [,2]
[1,] 0.6666667 -0.1666667
[2,] -0.3333333 0.3333333
my_matrix$getInverse()
[,1] [,2]
[1,] 0.6666667 -0.1666667
[2,] -0.3333333 0.3333333