comp.lang.idl-pvwave archive: archive » Re: Structure of arrays or arrays of structures?

Home » Public Forums » archive » Re: Structure of arrays or arrays of structures?

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

Re: Structure of arrays or arrays of structures? [message #64841 is a reply to message #64837]

Fri, 23 January 2009 00:11

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

Brian Larsen schrieb:
> All,
>
> this may be philosophy but I have fought with both today and I am
> wondering if there are pros and cons to the different
> implementations.
>
> My example is that when I read in text files I build a structure of
> arrays:
> IDL> help, data
> DATA STRUCT = -> <Anonymous> Array[1]
> IDL> help, data, /str
> ** Structure <1a07a08>, 5 tags, length=212480, data length=212480,
> refs=1:
> JD DOUBLE Array[5312]
> PAS0 DOUBLE Array[5312]
> PAS90 DOUBLE Array[5312]
> MEP0E3 DOUBLE Array[5312]
> MEP90E3 DOUBLE Array[5312]
>
> and when I read cdf data (at least from ACE) I get arrays of
> structures
> IDL> help, data
> DATA STRUCT = -> <Anonymous> Array[36451]
> IDL> help, data, /str
> ** Structure <19cf008>, 45 tags, length=200, data length=196, refs=1:
> DNUM DOUBLE 0.0000000
> YEAR LONG 2007
> DAY LONG 165
> HR LONG 0
> MIN LONG 0
> SEC FLOAT 8.98560
>
> Are there memory issues with one way or the other? Other things I
> haven't thought about?
>
> I prefer the feel of the structure of arrays since I like typing
> tmp = data.jd[0:10]
> more than I like typing
> tmp = data[0:10].jd

Hi

well with the last one you can quite easy create slices of your data set
by result = data[ix]. It also could be used with table widgets or for an
example by xvaredit.

Your prefered solution is easy to use for all kind of tag manipulation,
e.g. removing, renaming, adding another tag into the same structure.

Long time ago we have added reform_struct to our library.
http://www.fz-juelich.de/zb/datapool/page/439/00322_Bauer.pd f page 57
(text in german, examples in idl)

cheers
Reimar

>
>
> Cheers,
>
> Brian
>
> ------------------------------------------------------------ --------------
> Brian Larsen
> Boston University
> Center for Space Physics
> http://people.bu.edu/balarsen/Home/IDL

Report message to a moderator

[Message index]

		Re: Structure of arrays or arrays of structures? By: David Fanning on Fri, 23 January 2009 09:27
		Re: Structure of arrays or arrays of structures? By: Paul Van Delst[1] on Fri, 23 January 2009 09:25
		Re: Structure of arrays or arrays of structures? By: Brian Larsen on Fri, 23 January 2009 07:23
		Re: Structure of arrays or arrays of structures? By: R.Bauer on Fri, 23 January 2009 00:11
		Re: Structure of arrays or arrays of structures? By: Craig Markwardt on Thu, 22 January 2009 16:15
		Re: Structure of arrays or arrays of structures? By: TonyL on Thu, 22 January 2009 14:57
		Re: Structure of arrays or arrays of structures? By: Michael Galloy on Thu, 22 January 2009 14:32

Previous Topic:	Re: BAR_PLOT with pairs of bars
Next Topic:	A new version of GRAFFER

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Sat Oct 11 15:52:32 PDT 2025

Total time taken to generate the page: 2.47748 seconds