comp.lang.idl-pvwave archive - RDF feed
type: channel
description: Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
items: Huh?? Stddev went crazy!

Huh?? Stddev went crazy!
type: item
description: I'd like to see someone explain this one. My stddev function apparently lost all grasp on reality? IDL> print,stddev([1,2,3,4,5]) 3.07421 3.24566 3.08206 3.26360 2.97446 IDL> print,stddev([1.,2.,3.,4.,5.]) 3.07421 3.24566 3.08206 3.26360 2.97446 IDL> print,stddev([1.,2.]) 3.07421 3.24566 IDL> print,stddev(findgen(32)) 2.99513 3.07421 3.24566 3.08206 3.26360 2.97446 2.96850 3.04474 2.66875 2.77181 2.83465 2.77395 2.77370 2.87829 2.84716 2.86982 2.98503 2.93160 2.77602 2.59318 2.83169 3.30869 2.67353 3.15337 3.19076 3.19499 2.96050 3.13871 2.61707 2.77854 3.12603 3.20029 Finally I did this: IDL> .reset And it returned to normal! Yeah! IDL> print,stddev(findgen(32)) % Compiled module: STDDEV. % Compiled module: MOMENT. 9.38083 IDL> res = findgen(10,10) IDL> print,stddev(res) 29.0115 I have not been able to reproduce the crazy behavior since (not that I've tried very hard). Still, it's rather worrisome if the behavior of a built in function isn't reliable!!
creator: Conor
date: 2008-04-16T19:07:29-00:00