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<== Date ==> <== Thread ==>

Subject: RE: 'Feature' of subArray record
From: <graham.cox@stfc.ac.uk>
To: <anj@aps.anl.gov>, <tech-talk@aps.anl.gov>
Date: Tue, 15 Mar 2011 16:40:16 +0000
OK.  That all makes sense.

I just wanted to make sure I wasn't misunderstanding the fields of the subArray record and unnecessarily wasting memory.  

I will leave the subArray 2 MALM field set large enough to contain the full size of the waveform record.

Thanks for the help.

Graham

-----Original Message-----
From: Andrew Johnson [mailto:anj@aps.anl.gov] 
Sent: 15 March 2011 16:35
To: tech-talk@aps.anl.gov
Cc: Cox, Graham (STFC,DL,EID)
Subject: Re: 'Feature' of subArray record

Hi Graham,

On Tuesday 15 March 2011 11:07:22 graham.cox@stfc.ac.uk wrote:
> Should it not be the case that I can store the number of sample 
> allocated in MALM?  Otherwise I will be allocating memory which I will 
> never be using, in this case double the amount required in subArray 2 
> as MALM must equal (INDX + NELM) rather than simply NELM.
>
> Clearly I can get the system operating by setting MALM sufficiently 
> high in subArray 2, but it seems that MALM isn't quite doing what it 
> would be expected to do?

Unfortunately the API that the subArray device support uses to fetch the data from the waveform record does not include an offset parameter, so the code has to fetch the whole array and then dump the first INDX elements.  This is a limitation of the current dbGetLink() routine.  I could see ways to get around it, but nobody has tried writing the necessary code yet, so currently you will have to set your subArray 2's NELM field to the size of the waveform record.

HTH,

- Andrew
-- 
An error is only a mistake if you don't learn from it.
When you learn something from it, it becomes a lesson.

-- 
Scanned by iCritical.


References:
Re: 'Feature' of subArray record Andrew Johnson

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