[Halld-offline] hdparsim covariance matrix

[Matthew Shepherd]

Hi Will,

If you look in the DPhoton_factory inside of the libraries/PID, I believe you will find a method for constructing a proper error matrix for showers in the BCAL and FCAL given the uncertainties on energy and position.  This is not hard, one just has to do the proper coordinate transforms.  You can probably just copy this code somewhere for use in hdparsim. 

-Matt


On Mar 12, 2010, at 11:44 AM, Will Levine wrote:

> Hi everyone,
> I've just started working with Curits on the kinematic fitter, trying
> to get it to work with hdparsim. The kinematic fitter needs a
> covariance matrix for each particle, which hdparsim does not currently
> provide, so I have to construct a covariance matrix based on the
> parameters used to smear the particles. If this would be useful for
> others, I would of course be happy to contribute my code. Currently,
> I've modified hdparsim directly, so that it creates DParticles and
> DPhotons with a real error matrix. If this is somehow undesirable, I
> could try to do this work somewhere outside hdparsim. Thoughts?
> 
> Will
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