[Eg6_analysis] [Lowq] DC calibration issues

Sun Dec 12 10:52:45 EST 2010

Hi Seema,

Since in user_ana we are monitoring the DC means and sigmas with and
without the local angle cuts, we are calculating these variables in two
steps.
In the first step (without cuts) the DC residuals mean and sigmas (noted as
weighted mean and sigma in the monitoring web page) are calculated for each
superlayer and sector as:

weighted mean=
(abs(ggpar(1)*ggpar(3))*ggpar(2)+abs(ggpar(4)*ggpar(6))*ggpar(5))

/(abs(ggpar(1)*ggpar(3))+abs(ggpar(4)*ggpar(6)))*10000

whith an extra sign adjustment which is not used on dc3 formula.

 weighted sigma=
(abs(ggpar(1)*ggpar(3))*abs(ggpar(3))+abs(ggpar(4)*ggpar(6))*abs(ggpar(6)))

/(abs(ggpar(1)*ggpar(3))+abs(ggpar(4)*ggpar(6)))*10000

 where gpar is the fit parameter's vector.

However, with the local angle cuts, the residuals means and sigmas (noted as
small mean and
sigma in the monitoring page) are written to the CSQL database with the
following requirement:

        if(abs(ggpar(2)).lt.abs(ggpar(5))) then ! Comparing a narrow and
wide means like on dc3
         "small mean"= ggpar(2)*10000
        else                                               ! Always take the
smallest mean
          "small mean"= ggpar(5)*10000
        endif

        if(abs(ggpar(3)).lt.abs(ggpar(6))) then ! Comparing a narrow and
wide sigmas
         "small mean"= ggpar(3)*10000
            else                                            ! Always take
the smallest sigma
         "small sigma"= ggpar(6)*10000
        endif

In this case the smallest mean and sigma are taken directly from the fit
without any further calculation. So, I am not sure which set of parameters
(weighted or small) you are using to
compare with your DC results. I think since the dc calibration includes
similar cuts we may
need to compare dc results with the small variables but even though we will
still have some disagreement since we are not tuning the parameters anymore
after the fit.

Best regards,

Lamiaa

************************************************************
*  Lamiaa El Fassi             email: elfassi at jlab.org
*  Research Associate @ Rutgers University
*  Phone: (757) 269-7011 // Fax: (757) 269-5703
*  Jefferson Lab., 12000 Jefferson Ave.
*  Suite# 4, MS 12H3
*  Newport News, VA. 23606
************************************************************

On Wed, Dec 8, 2010 at 4:01 PM, <seema at jlab.org> wrote:

> Hello Everyone,
> Please have a look at the attached file dc_mean.pdf. This table compares
> the time residual means for run number 61695. The numbers in the
> parentheses are from dc3 software. These are the numbers from my last
> iteration. I could not run trk_mon on this new cooked file because TBLA
> bank was not there in this new version of dc cooking. We still have some
> disagreement. In dc3 software we have one more constraint before
> calculating the mean and that is :
> // Make sure narrow and wide didn't switch
>   if(PAR[2]>PAR[5]){
>      for(i=0;i<3;i++){
>         tmp=PAR[i];
>         PAR[i]=PAR[i+3];
>         PAR[i+3]=tmp;
>      }
>   }
>
>   *sigma_narrow    = 1.0E4*PAR[2];
>   *sigma_wide      = 1.0E4*PAR[5];
>   *amplitude_ratio = PAR[0]/PAR[3];
>   *mean            = ((PAR[0]*PAR[1]*PAR[2]) + (PAR[3]*PAR[4]*PAR[5]))
>                                        /((PAR[0]*PAR[2]) +(PAR[3]*PAR[5]));
> I am not sure if we have this condition implemented in user_ana.
> Please let me know if you have any questions.
> Best regards,
> Seema
>
>
> > Hi Seema,
> >
> > This can have significant effect.
> > What are the values in pmin and pmax arrays?
> > The initial parameters are close enough, the ratio of the first and
> > fourth parameters should be same,
> > the other parameters should start
> > with the same values. Also I  am
> > not sure if the number of parameters
> > matters in these calls, but I would make them identical too.
> >
> > I would suggest changing user_ana
> > to match the calibration procedure source.
> >
> > Hovanes
> >
> >
> >
> > Sent from my iPhone
> >
> > On Dec 5, 2010, at 5:01 PM, seema at jlab.org wrote:
> >
> >> Hello Everyone,
> >> I have checked once again the fitting function used in dc3  and user_ana
> >> software. Although double gaussian is used in each case but the starting
> >> parameters are not allowed to vary freely in user_ana and that may be
> >> the
> >> reason for inconsistency in time residual means.
> >>
> >> Functional form used in user_ana
> >>
> >> call hfithn(hid,'G+G','QB',0,ggpar,step,pmin,pmax,eggpar,chi2)
> >> ggpar(1) = 50000
> >> ggpar(2) = 0.
> >> ggpar(3) = 0.02
> >> ggpar(4) = 10000
> >> ggpar(5) = 0.
> >> ggpar(6) = 0.1
> >>
> >> Functional form used in dc3
> >>
> >> hfithn(HID,"g+g","Q",6,PAR,STEP,PMIN,PMAX,SIGPAR,&CHISQ);
> >>
> >> PAR[6] = {500.0, 0.0, 0.0300, 50.0, 0.0, 0.100}
> >>
> >> Please notice the extra  'B' option selected in user_ana and also the
> >> starting parameters are different!
> >>
> >> Best regards,
> >> Seema
> >>
> >>
> >>> Dear all,
> >>>
> >>> due to various activities, Hall closing, PAC deadline and so on,
> >>> tomorrow's eg6 meeting is canceled.
> >>>
> >>> Stepan
> >>> _______________________________________________
> >>> Lowq mailing list
> >>> Lowq at jlab.org
> >>> https://mailman.jlab.org/mailman/listinfo/lowq
> >>>
> >>
> >>
> >> _______________________________________________
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> >
>
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