| array dimensions [message #24591] |
Sat, 07 April 2001 04:16  |
francesco.spada
Messages: 8
Registered: April 2001
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Junior Member |
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Hi to everybody,
I have an array
myarray fltarr[dimx,dimy,dimz]
How can I get the value of dimx, dimy and dimz?
Whith n_elements I have only the total number.
Thanks
Ciao
Francesco
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| Re: array dimensions [message #24639 is a reply to message #24591] |
Tue, 10 April 2001 07:08  |
Paul van Delst
Messages: 364
Registered: March 1997
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Senior Member |
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"Richard G. French" wrote:
>
> Paul van Delst wrote:
>>
>> IF ( n GT 1 ) THEN SMOOTH( array, n )
>>
>> ?
> That's fine if you want this to be on a single line, but there are
> plenty
> of times when SMOOTH(array, n) is in a plot command, or in part of a
> complex
> expression. I think the argument about rebin is exactly similar - of
> course,
> you can do the checking ahead of time, but who wants to add this check
> for every time you do dynamic smoothing? adds lots of unneeded hair to
> the code. Smoothing by 1 is not the same as dividing by zero. It is like
> convolving with a one-element array, which IDL is perfectly willing to
> do without complaining and dying.
Fair enough. Complaining and dying is a decidedly poor response. I guess it would be nice
to be able to put a
IF ( n LE 1 ) THEN RETURN, array
or
IF ( n LE 1 ) THEN BEGIN
MESSAGE, 'N < or = 1, exiting...'
RETURN, array
ENDIF
as the first executable statement(s) in a smooth.pro, if it existed for users to meddle
with. I just checked the IDL documentation and it doesn't state that n=1 is invalid. In
fact, it is implicitly valid since it is an odd number. So, wouldn't the problem with
SMOOTH when n=1 be a bug ... that RSI should fix?
paulv
--
Paul van Delst A little learning is a dangerous thing;
CIMSS @ NOAA/NCEP Drink deep, or taste not the Pierian spring;
Ph: (301)763-8000 x7274 There shallow draughts intoxicate the brain,
Fax:(301)763-8545 And drinking largely sobers us again.
paul.vandelst@noaa.gov Alexander Pope.
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| Re: array dimensions [message #24640 is a reply to message #24591] |
Tue, 10 April 2001 07:06 |
Carsten Dominik
Messages: 45
Registered: February 1998
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Member |
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>>>> > "MS" == Martin Schultz <martin.schultz@dkrz.de> writes:
MS> Mark Hadfield wrote:
>>
>> Damn, I'm running out of excuses not to use that thing !
>>
MS> Just say you work on a Windows computer ;-)
Thats no excuse. Only the shell is not working under windows, all the
rest is.
- Carsten
MS> Martin
MS> PS: for Pavel - delete "Windows" insert "Mac"
MS> --
MS> [[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
MS> [[ Dr. Martin Schultz Max-Planck-Institut fuer Meteorologie [[ [[
MS> Bundesstr. 55, 20146 Hamburg [[ [[ phone: +49 40 41173-308 [[ [[
MS> fax: +49 40 41173-298 [[ [[ martin.schultz@dkrz.de [[
MS> [[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
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| Re: array dimensions [message #24646 is a reply to message #24591] |
Tue, 10 April 2001 03:42 |
Martin Schultz
Messages: 515
Registered: August 1997
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Senior Member |
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Mark Hadfield wrote:
>
> From: "JD Smith" <jdsmith@astro.cornell.edu>
>> ...
>> So it seamlessly integrates help (and calling syntax, and keyword lists,
>> and completion, and...) from all external libraries too, and even from
>> your own routine collection! This is the reason I have started to use
>> well formed documentation headers again (also because inserts
>> one automatically for me, and puts the date, my name, etc. for
>> a Modification Entry). Even if you don't have a good doc header,
>> IDLWAVE pulls up the routine declaration.
>
> Damn, I'm running out of excuses not to use that thing !
>
Just say you work on a Windows computer ;-)
Martin
PS: for Pavel - delete "Windows" insert "Mac"
--
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
[[ Dr. Martin Schultz Max-Planck-Institut fuer Meteorologie [[
[[ Bundesstr. 55, 20146 Hamburg [[
[[ phone: +49 40 41173-308 [[
[[ fax: +49 40 41173-298 [[
[[ martin.schultz@dkrz.de [[
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
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| Re: array dimensions [message #24647 is a reply to message #24591] |
Tue, 10 April 2001 03:37 |
Martin Schultz
Messages: 515
Registered: August 1997
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Senior Member |
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Paul van Delst wrote:
>
>
> I type "size" <Enter> in the Online help window (after alt-tab-ing to the app, or moving
> mouse over app).
Try this with PLOT ;-)
You'll see plot object, plot ..., plot ... and only somewhere way down
the list you find what you were looking for. In the idlwave shell,
it's
IDL> plot
and here are your PLOT keywords.
> Help on size() is displayed for me and, if required <pageDown> gets me to
> "DIMENSIONS"
well, yes. But how many "page downs". Wait until you write widget
code. What did I read yesterday in David's book: there are over 60
keywords to widget_info alone!
Cheers,
Martin
--
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
[[ Dr. Martin Schultz Max-Planck-Institut fuer Meteorologie [[
[[ Bundesstr. 55, 20146 Hamburg [[
[[ phone: +49 40 41173-308 [[
[[ fax: +49 40 41173-298 [[
[[ martin.schultz@dkrz.de [[
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
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| Re: array dimensions [message #24653 is a reply to message #24591] |
Mon, 09 April 2001 20:29 |
Richard French
Messages: 173
Registered: December 2000
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Senior Member |
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Paul van Delst wrote:
>
> IF ( n GT 1 ) THEN SMOOTH( array, n )
>
> ?
That's fine if you want this to be on a single line, but there are
plenty
of times when SMOOTH(array, n) is in a plot command, or in part of a
complex
expression. I think the argument about rebin is exactly similar - of
course,
you can do the checking ahead of time, but who wants to add this check
for every time you do dynamic smoothing? adds lots of unneeded hair to
the code. Smoothing by 1 is not the same as dividing by zero. It is like
convolving with a one-element array, which IDL is perfectly willing to
do
without complaining and dying.
DIck French
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| Re: array dimensions [message #24655 is a reply to message #24591] |
Mon, 09 April 2001 14:07 |
m.hadfield
Messages: 36
Registered: April 2001
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Member |
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From: "JD Smith" <jdsmith@astro.cornell.edu>
> ...
> So it seamlessly integrates help (and calling syntax, and keyword lists,
> and completion, and...) from all external libraries too, and even from
> your own routine collection! This is the reason I have started to use
> well formed documentation headers again (also because [C-c C-h] inserts
> one automatically for me, and [C-c Ret] puts the date, my name, etc. for
> a Modification Entry). Even if you don't have a good doc header,
> IDLWAVE pulls up the routine declaration.
Damn, I'm running out of excuses not to use that thing !
---
Mark Hadfield
m.hadfield@niwa.cri.nz http://katipo.niwa.cri.nz/~hadfield
National Institute for Water and Atmospheric Research
--
Posted from clam.niwa.cri.nz [202.36.29.1]
via Mailgate.ORG Server - http://www.Mailgate.ORG
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| Re: array dimensions [message #24656 is a reply to message #24591] |
Mon, 09 April 2001 11:09 |
John-David T. Smith
Messages: 384
Registered: January 2000
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Senior Member |
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Paul van Delst wrote:
>
> JD Smith wrote:
>>
>> Paul van Delst wrote:
>>>
>>> Martin Schultz wrote:
>>>>
>>>> Not a favorite keyword, but a favorite tool: Get a decent system (if
>>>> you haven't one), install emacs with idlwave, run the routine-info
>>>> collection, and then you have all the keywords you never knew but
>>>> always dreamt about literally at your fingertips.
>>>
>>> Similar to typing "?" at the IDL prompt and getting similar info - with examples no less!
>>> Gasp!
OK, just to make the distinction crystal clear: With the RSI online
help, you can search through the index, by typing "size" for example.
This (sometimes) puts you on the routine in question. Hmm, in this
case, it pulls up "SIZE Executive Command". Luckily "SIZE Function" is
the next entry. Try "window" though. Hmm... window object, color
model..., WINDOW system variable, etc. In any case, once you've
(finally) targetted in on your routine of choice, you open up the help
topic (e.g. for WINDOW Procedure) by double-clicking. Sometimes it
opens right away. In this case (and many others), it wants more
information. Do I really want "WINDOW", or perhaps I'm interested in
"Window Systems". OK, "WINDOW" it is. Finally the routine
documentation opens and I can scroll through manually looking for
keywords.
IDLWAVE does all these operations for you instantaneously. If you're
sitting on:
window,PIXMAP=
and invoke help, IDLWAVE *knows* you're not looking for the !D.WINDOW
system variable, or random notes about window objects, or windowing
functions, or window washing, etc. It knows you'd like some info on the
"PIXMAP" keyword to the "WINDOW" procedure, and dials directly and
instantaneously to:
PIXMAP
Set the PIXMAP keyword to specify that
the window being created is actually an
invisible portion of the display memory called a pixmap.
You get the info you need on the
routine/procedure/keyword/system_variable at hand, and get on with your
work. I invoke help this way so much now I don't even notice it
really. It has become an integral part of my coding technique. As
someone who spent many an hour doing it the RSI way with their help
browser (type into index name, (possibly) scroll down nearby because it
found the wrong thing, double-click, (possibly) dismiss another pop-up,
scroll down looking for keywords, etc.), I can guarantee you the IDLWAVE
way is *much* faster. It may not be for everyone, but it sure saves me
lots of time. One consideration before you throw out the online
manuals: IDLWAVE's version is text only, so those cool formatted
mathematics and graphics don't make it through very well. This is not a
problem 99.5% of the time. I keep RSI's browser handy for the other
0.5%.
I can get at help in many ways: through a keyword completion list,
through the routine info, by C-S right clicking on anything (keyword,
routine, system variable, object, obj_new invocation, etc.) in the
buffer *or* shell, etc.
And here's the best. Lest we not forget some of the best IDL routines
are not supplied by RSI... if there is no system help topic for a
routine you invoke help on, but its source code is available, that will
be loaded up instead. If the source code has a standard documentation
header, it will be visited for keywords (with a keyword section), and
syntax too. E.g. the nasa procedure, FITS_WRITE:
IDL> fits_write, NANVALUE=
Invoke help... presto:
;NaNvalue: data value in DATA to be replaced with IEEE NaN in the output
; file.
...
So it seamlessly integrates help (and calling syntax, and keyword lists,
and completion, and...) from all external libraries too, and even from
your own routine collection! This is the reason I have started to use
well formed documentation headers again (also because [C-c C-h] inserts
one automatically for me, and [C-c Ret] puts the date, my name, etc. for
a Modification Entry). Even if you don't have a good doc header,
IDLWAVE pulls up the routine declaration.
Never be without routine/syntax/keyword/sysvar/object_method information
again.
JD
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| Re: array dimensions [message #24657 is a reply to message #24591] |
Mon, 09 April 2001 10:57 |
Carsten Dominik
Messages: 45
Registered: February 1998
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Member |
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>>>> > "JS" == JD Smith <jdsmith@astro.cornell.edu> writes:
JS> Not even *sort of* similar. Yes, it's the same information
JS> (Carsten simply process the pdf manuals to get the documentation).
I heavily object to "simply". This was one hell of a job, to
reverse-engineer thousands of pages of (not always consistent)
documentation.
:-)
- Carsten
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| Re: array dimensions [message #24658 is a reply to message #24591] |
Mon, 09 April 2001 09:49 |
Paul van Delst
Messages: 364
Registered: March 1997
|
Senior Member |
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JD Smith wrote:
>
> Paul van Delst wrote:
>>
>> Martin Schultz wrote:
>>>
>>> Not a favorite keyword, but a favorite tool: Get a decent system (if
>>> you haven't one), install emacs with idlwave, run the routine-info
>>> collection, and then you have all the keywords you never knew but
>>> always dreamt about literally at your fingertips.
>>
>> Similar to typing "?" at the IDL prompt and getting similar info - with examples no less!
>> Gasp!
>
> Not even *sort of* similar. Yes, it's the same information (Carsten
> simply process the pdf manuals to get the documentation). But the
> access is amazingly better. Example:
>
> IDL> d=size(myvar,/
>
> Hmm what was that keyword to size? I'll hit [Tab] to see. Up comes:
I type "size" <Enter> in the Online help window (after alt-tab-ing to the app, or moving
mouse over app).
>
> Possible completions are:
> DIMENSIONS FILE_LUN
> L64 N_DIMENSIONS
> N_ELEMENTS STRUCTURE
> TNAME TYPE
>
> Aha, DIMENSIONS, I think that's it. Why don't I right click on it to
> find out. Up pops in the help window with help on size() displayed,
Help on size() is displayed for me and, if required <pageDown> gets me to "DIMENSIONS"
> and queued up to:
>
> DIMENSIONS
> Set this keyword to return the dimensions
> of Expression. If Expression is scalar, the
> result is a scalar containing a 0. For arrays,
> the result is an array containing the array
> dimensions. ...
>
> OK, dimensions it is, middle click on it:
don't take my hands off keyboard, but
> IDL> d=size(myvar,/DIMENSIONS
that's pretty neat (inserting it automagically like that).
> Aren't there some other arguments to size()? I don't recall. I'll just
> show the calling syntax. [C-c ?]. Here comes:
>
> Usage: Result = SIZE( Expression)
> Keywords: DIMENSIONS FILE_LUN L64 N_DIMENSIONS N_ELEMENTS STRUCTURE
> TNAME TYPE
> Source: Builtin
I get that up front.
>
> Hmm. I guess not. But what is that STUCTURE keyword all about. I don't
> remember that one. Why not right click on it (it's blue, which means it
> exists in the help).
Once again: <pageDown> (if required)
> STRUCTURE
> Set this keyword to return all available
> information about Expression in a structure.
>
> OK, I'll file that away for a rainy day.
Me too.
> As you can see, you soon
> become intimately aware of all the keywords in all your favorite
> routines, and able to summon them into existence with a few keystrokes.
Me too.
> One positive side effect of keyword completion is that I am no longer
> lazy when it comes to partial keywords (OK I'm still lazy, but IDLWAVE
> is not). No longer is my code littered with framents like
> "a=size(var,/DIME)" and other non-sequiturs.
I never did that anyway (except for /INFO instead of /INFORMATIONAL since "info" is a
common, understood contraction.) since I have an horrendous memory - but I concede that
keyword completion is an extremely handy/good-for-eliminating-fat-finger-errors type of
thing. When I first started using emacs, I found there was just too many
ctrl-alt-esc-shift-meta-letter/number sequences to remember.
Diffr'nt strokes, I guess.
paulv
--
Paul van Delst A little learning is a dangerous thing;
CIMSS @ NOAA/NCEP Drink deep, or taste not the Pierian spring;
Ph: (301)763-8000 x7274 There shallow draughts intoxicate the brain,
Fax:(301)763-8545 And drinking largely sobers us again.
paul.vandelst@noaa.gov Alexander Pope.
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| Re: array dimensions [message #24659 is a reply to message #24591] |
Mon, 09 April 2001 09:25 |
John-David T. Smith
Messages: 384
Registered: January 2000
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Senior Member |
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Paul van Delst wrote:
>
> Martin Schultz wrote:
>>
>> "Richard G. French" wrote:
>>>
>>> David Fanning wrote:
>>>> > dimensions = Size(myarray, /Dimensions)
>>>>
>>>> Cheers,
>>>
>>> David is the master of keywords - I've used SIZE all these years without
>>> knowing that there was a /DIMENSIONS keyword. I guess the only way to
>>> know about these things is to read through the documentation over and
>>> over again and take notes on potentially useful keywords and options.
>>>
>>> Which brings me to my question - does anyone out there have a favorite
>>> keyword on a routine that we mere mortals might not know about, but
>>> which
>>> might make our lives much easier? Any suggestions welcome, except for
>>> HISTOGRAM and PLOT!
>>>
>>> Dick French
>>
>> Not a favorite keyword, but a favorite tool: Get a decent system (if
>> you haven't one), install emacs with idlwave, run the routine-info
>> collection, and then you have all the keywords you never knew but
>> always dreamt about literally at your fingertips.
>
> Similar to typing "?" at the IDL prompt and getting similar info - with examples no less!
> Gasp!
Not even *sort of* similar. Yes, it's the same information (Carsten
simply process the pdf manuals to get the documentation). But the
access is amazingly better. Example:
IDL> d=size(myvar,/
Hmm what was that keyword to size? I'll hit [Tab] to see. Up comes:
Possible completions are:
DIMENSIONS FILE_LUN
L64 N_DIMENSIONS
N_ELEMENTS STRUCTURE
TNAME TYPE
Aha, DIMENSIONS, I think that's it. Why don't I right click on it to
find out. Up pops in the help window with help on size() displayed, and
queued up to:
DIMENSIONS
Set this keyword to return the dimensions
of Expression. If Expression is scalar, the
result is a scalar containing a 0. For arrays,
the result is an array containing the array
dimensions. ...
OK, dimensions it is, middle click on it:
IDL> d=size(myvar,/DIMENSIONS
Aren't there some other arguments to size()? I don't recall. I'll just
show the calling syntax. [C-c ?]. Here comes:
Usage: Result = SIZE( Expression)
Keywords: DIMENSIONS FILE_LUN L64 N_DIMENSIONS N_ELEMENTS STRUCTURE
TNAME TYPE
Source: Builtin
Hmm. I guess not. But what is that STUCTURE keyword all about. I don't
remember that one. Why not right click on it (it's blue, which means it
exists in the help).
STRUCTURE
Set this keyword to return all available
information about Expression in a structure.
OK, I'll file that away for a rainy day. As you can see, you soon
become intimately aware of all the keywords in all your favorite
routines, and able to summon them into existence with a few keystrokes.
One positive side effect of keyword completion is that I am no longer
lazy when it comes to partial keywords (OK I'm still lazy, but IDLWAVE
is not). No longer is my code littered with framents like
"a=size(var,/DIME)" and other non-sequiturs.
This is not to mention help with finding the correct routine in the
first place. I haven't thrown away my regular on-line data-files, I
just visit them only about once a month.
To see (and work through) even more examples, have a look at the
tutorial:
http://www.strw.LeidenUniv.nl/~dominik/Tools/idlwave/idlwave .html#SEC3
JD
P.S. There are a couple of new features in the offing for an IDLWAVE
release. If you've ever been tired of the wait for routine info to
load, look for a nice improvement "real soon now". A nice new
drag-to-print feature for instant debugging fun is also in the works.
Stay tuned.
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| Re: array dimensions [message #24662 is a reply to message #24591] |
Mon, 09 April 2001 08:51 |
davidf
Messages: 2866
Registered: September 1996
|
Senior Member |
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James Kuyper (kuyper@wizard.net) writes:
> It would have occurred to me; part of my group's standard testing
> routine is to check all boundary cases, which would have focused my
> attention on n=1.
Yeah, but I put guys who follow standard testing routines
right up there with guys who always hit the right tennis
shot. I mean, gosh, where's the let-it-all-hang-out
passion? Where's the juice? Where's the hell-bent-for-leather,
smash-it-down-his-throat winner?
Cheers,
David
P.S. Let's just say I've *never* understood, either, why
God lets those other guys win all the time. :-(
--
David Fanning, Ph.D.
Fanning Software Consulting
Phone: 970-221-0438 E-Mail: davidf@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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| Re: array dimensions [message #24666 is a reply to message #24591] |
Mon, 09 April 2001 08:18 |
Martin Schultz
Messages: 515
Registered: August 1997
|
Senior Member |
|
|
Paul van Delst wrote:
>
> Martin Schultz wrote:
>>
>> "Richard G. French" wrote:
>>>
>>> David Fanning wrote:
>>>> > dimensions = Size(myarray, /Dimensions)
>>>>
>>>> Cheers,
>>>
>>> David is the master of keywords - I've used SIZE all these years without
>>> knowing that there was a /DIMENSIONS keyword. I guess the only way to
>>> know about these things is to read through the documentation over and
>>> over again and take notes on potentially useful keywords and options.
>>>
>>> Which brings me to my question - does anyone out there have a favorite
>>> keyword on a routine that we mere mortals might not know about, but
>>> which
>>> might make our lives much easier? Any suggestions welcome, except for
>>> HISTOGRAM and PLOT!
>>>
>>> Dick French
>>
>> Not a favorite keyword, but a favorite tool: Get a decent system (if
>> you haven't one), install emacs with idlwave, run the routine-info
>> collection, and then you have all the keywords you never knew but
>> always dreamt about literally at your fingertips.
>
> Similar to typing "?" at the IDL prompt and getting similar info - with examples no less!
Not quite, because after "?" you still need to navigate around in
several index lists etc. before you find the calling syntax. But, of
course, the information itself is the same - that's where Carsten took
it from ;-)
Martin
--
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
[[ Dr. Martin Schultz Max-Planck-Institut fuer Meteorologie [[
[[ Bundesstr. 55, 20146 Hamburg [[
[[ phone: +49 40 41173-308 [[
[[ fax: +49 40 41173-298 [[
[[ martin.schultz@dkrz.de [[
[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[[ [[[[[[[
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