[lsst-dm-stack-users] LsstSimMapper questions

[Chris Walter]

Hi Kian-Tat,

Thanks for the answer.

> Is the value of VERSION literally "none" or is it just empty?  I'm not
> sure that an empty value is legal FITS.  In any case, I'd be tempted to
> say the fault is PhoSim's on this one.

I think literally 'none'.

metaData    = exposure.getMetadata()
metaData.get('VERSION')

returns 'none'.

> 
> Some workarounds are:
> 
> 1) Set the _DefaultName to something that already has a _config dataset
> defined (as you found out).

Yes, but this has unwanted consequences.  For example, if you use 'processCcd' an override file is loaded which sets up ISR tasks.  I don't want these because I need to look at unprocessed sensor data.  Would it be possible to make a generic entry for each datatype? "raw", "image" etc?

> 2) Override _getConfigName() and _getMetadataName() to return None,
> bypassing writing the config and metadata (but not bypassing the writing
> of schemas, if you define them by overriding getSchemaCatalogs()).
> 
> 3) Override writeConfig(), writeSchemas(), and writeMetadata() to do
> nothing (or write using something other than the butler).
> 

OK, thanks for the suggestion.  I need to read more code to understand these options.  I will do that.

-Chris

> 4) Override the TaskRunner's precall() and __call__() to not write
> these.
> 
> Of these, I think #2 or #3 may be your best bets.
> 
> -- 
> Kian-Tat Lim, LSST Data Management, ktl at slac.stanford.edu