comp.lang.idl-pvwave archive: archive » JULDAY 5.4 not same as 5.3?

Home » Public Forums » archive » JULDAY 5.4 not same as 5.3?

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: JULDAY 5.4 not same as 5.3? [message #24050 is a reply to message #23992]

Mon, 05 March 2001 14:22

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

pit@phys.uu.nl (Peter Suetterlin) writes:
...
> I'm still not sure who's to blame, me (i.e. the programmer) or
> IDL/RSI, but in general it does not make sense to take a negative of a
> unsigned number, and IMHO there should also occur an automatic type
> conversion as soon as a minus sign is involved. Currently, you get e.g.
>
> IDL> x=5b
> IDL> print,-x
> 251

We can argue all day about what is correct mathematically.

However I think it is correct from a microprocessor standpoint (ie,
that's what the processor does). Further more it satisfies certain
identities like:

(-x) + x EQ 0

And what would you do with a number like -('ffffffff'xul), ie a number
that to begin with is too large to fit into a signed type.

Finally, you would have the people (like me) who would gripe about how
IDL changed the type of a variable without asking me first!

Craig

--
------------------------------------------------------------ --------------
Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
------------------------------------------------------------ --------------

Report message to a moderator

[Message index]

		JULDAY 5.4 not same as 5.3? By: Don Woodraska on Thu, 01 March 2001 15:00
		Re: JULDAY 5.4 not same as 5.3? By: pit on Tue, 06 March 2001 09:23
		Re: JULDAY 5.4 not same as 5.3? By: Mark Hadfield on Mon, 05 March 2001 14:57
		Re: JULDAY 5.4 not same as 5.3? By: Craig Markwardt on Mon, 05 March 2001 14:22
		Re: unsigned int woes (was: JULDAY 5.4 not same as 5.3?) By: Martin Schultz on Mon, 19 March 2001 06:19
		Re: JULDAY 5.4 not same as 5.3? By: pit on Mon, 05 March 2001 10:03
		Re: JULDAY 5.4 not same as 5.3? By: Mark Hadfield on Sun, 04 March 2001 12:14

Previous Topic:	Linux and 3D graphics hardware support
Next Topic:	BETTER FONTS

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Nov 28 23:12:10 PST 2025

Total time taken to generate the page: 0.56021 seconds