[G12] Kinefitter

[Pedersen, Christopher]

Yes what you sent me is very similar to what is on Dustin's web site except for additions that handle electrons and that in the __multi = false case for some reason p_offset is scaled by 2.5 in the code. This is one of the factors I had to adjust that you claimed you had never heard of someone changing before. Here is the only output from diff between what you sent me and what is on Dustin's web site that doesn't involve additions for electrons:

282,283c285,286
<        p_offset = pPars[part_index][sector-1][bin][2];
<        V(3*i+1,3*i+1) += p_offset*p_offset + 2*p_offset*sqrt(V(3*i+1,3*i+1));
---
>        p_offset = 2.5*(pPars[part_index][sector-1][bin][2]);
>        V(3*i+1,3*i+1) += p_offset*p_offset + 2*p_offset*sqrt(fabs(V(3*i+1,3*i+1)));

Where the top is directly from Dustin's web site and the bottom is what you sent me. This is almost certainly the reason that the momentum pulls using the fitter as you sent it are too narrow and the rise in the confidence level toward 1 as this significantly increases the entries for momentum in the covariance matrix.

Chris
________________________________________
From: g12-bounces at jlab.org [g12-bounces at jlab.org] on behalf of Michael C. Kunkel [mkunkel at jlab.org]
Sent: Thursday, May 22, 2014 11:52 PM
To: g12; Volker Crede
Subject: [G12] Kinefitter

Greetings,

I wanted to point out that the fitter FSU has and g12 has been using for
multi = true has been tuned by Dustin himself.

Please read
https://userweb.jlab.org/~dustin/software/Makeshift/HowTo/G12-Testing/

I know I said Georgie tuned it, he did, and found no discrepancy with
Dustin's tune.

BR
MK
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