[Casa-framework] 'pix' unit (was ia.moments)

[Raymond Rusk]

Hi David,

The issue came up in the first place because I failed to include

 	UnitMap::putUser("pix",UnitVal(1.0), "pixel units");

in the ia.moments() implementation.  I fixed that and checked it into the 
svn repository so it should no longer be a problem.  No one has gotten 
back to me about moments() so I am taking that as a good sign.

I am finding plenty of other problems in image as I am just now beginning 
to test it.  There will be some significant updates to the implementation 
in a couple of days.

Raymond

On Tue, 5 Dec 2006, David King wrote:

> Just a tiny additional note on "pix" units, (which I am stumbling through at
> the moment):
>
> As Wim indicates, "pix" isn't a valid unit string until you define it to be.
>  A one-shot (and static) routine WCBox::unitInit() is WCBox's way of
> accomplishing that, so that "pix" Units can be used subsequently in such
> regions (or anywhere else); it is called in all the WCBox constructors.
> (WCPoly has a similar routine.  I believe the WCRegion classes most actively
> support "pix" and essentially define its semantics).
>
> Unfortunately, defining "pix" in the WCBox constructors is not quite soon
> enough, if you want to pass "pix" Quanta _to_ those constructors;
> furthermore, unitInit() is private.  As a workaround:
>
>   WCBox dummy;
>
> ...will do the trick.  But I think making unitInit() public is slightly
> cleaner, and could do no conceivable harm.  Any opinion, Ger (or others)?
>
> dk
>
>
>>> Lindsey Davis wrote:
>>> I am trying to use the moments task on an image whose shape is
>>>
>>> [256L, 256L, 1L, 31L]
>>>
>>> I tried both
>>>
>>> rtn = ia.moments([0],3)
>>> rtn = ia.moments([0],4)
>>>
>>> because I am not sure how degenerate axes are handled but
>>> both give the following error
>>>
>>> ed Nov 29 22:46:54 2006    SEVERE image::moments:
>>> Exception Reported: Unit::check Illegal unit string 'pix'
>
>
> Wim.Brouw at csiro.au wrote:
>
>> During the images production Neil wanted to be able to let the user
>> specify things like 'pix' 'piel' 'beam' etc.
>> The quanta can handle that (like it does in the case of FITS where
>> things lik Km KM JY sec SEC etc are used) by having a user unit 'map'
>> that can be filled at will. (pix e.g. is equanled to the countable non
>> dimensional unit '_').
>> In the original design this user map was a global static map; i.e. there
>> should be persistence soemwhere).
>
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-- 
Dr. Raymond Rusk                                        Dr. Raymond Rusk
ALMA Software Engineer                           Ingenieur Logiciel ALMA
National Research Council Canada   Conseil national de recherches Canada
Herzberg Institute of Astrophysics   L'Institut Herzberg d'Astrophysique
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Raymond.Rusk at nrc-cnrc.gc.ca                  Raymond.Rusk at nrc-cnrc.gc.ca