analysis/

mg_n_smallest.pro

Routines

top mg_n_smallest

result = mg_n_smallest(data, n [, /largest])

Finds the n smallest elements of a data array. This algorithm works fastest on uniformly distributed data. The worst case for it is a single smallest data element and all other elements with another value. This will be nearly equivalent to just sorting all the elements and choosing the first n elements.

Return value

index array

Parameters

data in required type=numeric array

data array of any numeric type (except complex/dcomplex)

n in required type=integer

number of smallest elements to find

Keywords

largest in optional type=boolean: set to find n largest elements

Examples

For example, to find the 3 smallest values of 10 random values, try:

  IDL> r = randomu(seed, 10)
  IDL> print, r, format='(4F)'
        0.6297589      0.7815896      0.2508559      0.7546844
        0.1353382      0.1245834      0.8733745      0.0753110
        0.8054136      0.9513228
  IDL> ind = mg_n_smallest(r, 3)
  IDL> print, r[ind]
        0.0753110     0.124583     0.135338

File attributes

Modification date:	Wed May 14 15:07:14 2014
Lines:	28
Docformat:	rst rst

Personal library of Michael Galloy
Contact me if you have enhancement requests or bug fixes.

mglib

Personal IDL library for M. Galloy