is.increasing: Diagnosis an increasing function
In FuzzyNumbers.Ext.2: Apply Two Fuzzy Numbers on a Monotone Function

Description Usage Arguments Value See Also Examples

View source: R/is.increasing.R

is.increasing tests if the introduced one-variable function is increasing (or in fact, non-decreasing) on the considered x.bound or not. In other words, is.increasing returns TRUE if the introduced function is increasing on the considered x.bound; and it returns FALSE otherwise. The goal of introducing function is.increasing in package FuzzyNumbers.Ext.2 is using in function f2apply.

1	is.increasing(fun, x.bound = c(-1, 1), step = 0.01)

`fun`	a one-variable R function
`x.bound`	a vector with two real ordered elements which determine a bound on x-axis for checking the monotonic of the considered function
`step`	a positive real-valued number which determine the increment of the considered sequence for checking the monotonic of the considered function. The default of `step` is 0.01. Increasing `step` value can cause the decreasing the time of computation and also couse the decreasing the precision of the calculations.

TRUE for increasing one-variable functions on the considered x.bound; otherwise FALSE

is.decreasing

is.increasing(fun=function(x) 2*x, x.bound=c(4,6), step=.1)

g = function(x) x^2
is.increasing(g, x.bound=c(-24,6), step=.01)

h = function(x) x^5
is.increasing(h, c(-24,6), .01)
curve(h(x), xlim=c(-2,2))


## The function is currently defined as
function (fun, x.bound = c(-1, 1), step = 0.01) 
{
    x = seq(x.bound[1], x.bound[2], by = step)
    i = 1
    while (fun(x[i]) <= fun(x[i + 1])) {
        if (i < length(x) - 1) {
            i <- i + 1
        }
        else (return(TRUE))
    }
    return(FALSE)
  }