isMonotonic

Check a one dimensional array to see if it is monotonic.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl" ; This library is automatically loaded
 ; from NCL V6.2.0 onward.
 ; No need for user to explicitly load.
	function isMonotonic (
		x [*] : numeric 
	)

Arguments

A one-dimensional numeric array.

Return value

Returns

 0 if the array is not monotonic.
 1 if the array is monotonically increasing.
 -1 if the array is monotonically decreasing.

Description

Applies a simple test for monotonicity. An array is monotonically increasing if each value increases and monotonically decreasing if each value decreases.

Examples

Example 1

 load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
 x = ispan(1,10,1)
 y = -x
 z = (/-5.2,-4.3,-2.2, 0, 1.7, -4.1, 9.9/)
 i = isMonotonic(x) ; i= 1
 i = isMonotonic(y) ; i=-1
 i = isMonotonic(z) ; i= 0