Re: "nan" in the energy of the DBCALPhoton

[Blake Leverington <leverinb@uregina.ca>]

I've committed it to the trunk now as well.

-Blake

Alexander Somov wrote:
> Could you also commit all your latest changes to trunk
> (rather than release-2009-02-24) to be sure that they
> will appear in the next lib release.
>
> Thanks,
>        Alex
>
>
> On Fri, 3 Jul 2009, Alexander Somov wrote:
>
>> Hi Blake,
>>
>> Thanks a lot for your prompt reply; I will check and
>> tell you if i find anything fishy.
>>
>> Cheers,
>>       Alex
>>
>>
>> On Thu, 2 Jul 2009, Blake Leverington wrote:
>>
>>> Hi Alex,
>>>
>>> I've updated the DBCALPhoton_factory.cc file and checked it in with 
>>> better correction parameters and functions that should avoid any 
>>> negative values in the base for pow. There shouldn't be any nan 
>>> values now.  If there is still a problem, let me know. (I think I've 
>>> checked it in properly anyway.)
>>>
>>> -Blake
>>>
>>> Blake Leverington wrote:
>>>> Hi Alex,
>>>>
>>>> I'll look at this today.
>>>>
>>>> -Blake
>>>>
>>>> Alexander Somov wrote:
>>>>> Hi Matt,
>>>>>
>>>>> Thanks for the prompt reply and explanations.
>>>>> Blake, could you please take a look on this
>>>>> reconstruction feature.
>>>>>
>>>>> Thanks,
>>>>>        Alex
>>>>>
>>>>>
>>>>> On Tue, 30 Jun 2009, Matthew Shepherd wrote:
>>>>>
>>>>>>
>>>>>> Hi Alex,
>>>>>>
>>>>>> This particular section of code was added by Blake recently to 
>>>>>> try to improve reconstruction at the end of the module.  I'm not 
>>>>>> familiar with it -- Blake, can you help Alex?
>>>>>>
>>>>>> Indeed it looks like the problem is trying to call pow with a 
>>>>>> negative base. That will certainly generate nan.
>>>>>>
>>>>>> -Matt
>>>>>>
>>>>>> On Jun 30, 2009, at 5:04 PM, Alexander Somov wrote:
>>>>>>
>>>>>>>
>>>>>>> Hi Matt,
>>>>>>>
>>>>>>> I have found a few events in the BCAL reconstruction
>>>>>>> where the photon energy is not calculated properly.
>>>>>>> Below is a typical example:
>>>>>>>
>>>>>>> DBCALPhoton:
>>>>>>>     x:      y:      z:    px:    py:    pz:     E:
>>>>>>> ----------------------------------------------------
>>>>>>> 56.62   37.97  133.08   0.12   0.08   0.15   0.21
>>>>>>> -9.08   67.51  211.40  -0.06   0.46   1.01   1.11
>>>>>>> -64.92   23.81  306.27  -0.45   0.16   1.67   1.74
>>>>>>> 19.78  -62.68  405.37    nan    nan    nan    nan    <---
>>>>>>> 61.69  -31.96  397.37   0.01  -0.00   0.05   0.05
>>>>>>>
>>>>>>> DBCALShower:
>>>>>>>     x:      y:      z:     t:     E:
>>>>>>> --------------------------------------
>>>>>>> 56.62   37.97  133.08   6.11   0.18
>>>>>>> -9.08   67.51  211.40   5.40   1.04
>>>>>>> -64.92   23.81  306.27   8.38   1.61
>>>>>>> 19.78  -62.68  405.37  11.77   0.51    <---
>>>>>>> 61.69  -31.96  397.37  12.55   0.03
>>>>>>>
>>>>>>> The problem appears at the  edge of the BCAL, specifically
>>>>>>> in the DBCALPhoton_factory.cc file where the energy of a
>>>>>>> photon  is calculated (for zEntry >= 370.0 ):
>>>>>>>
>>>>>>> double energy = pow( ((**showItr).E - lin ) / scale, 1 / ( 1 + 
>>>>>>> nonlin ) );
>>>>>>> lin    -0.08144
>>>>>>> nonlin -0.616129
>>>>>>> scale  -0.0563619
>>>>>>> **showItr 0.505658  (shower energy)
>>>>>>> energy nan
>>>>>>>
>>>>>>> pow(x,y) is called here with the negative x.
>>>>>>>
>>>>>>> Could you please check the callibration coefficients in the 
>>>>>>> DBCALPhoton_factory.cc
>>>>>>> factory (I have no clue how these coefficients have been 
>>>>>>> obtained). I would like to finish  with the acceptance studies 
>>>>>>> shortly.
>>>>>>>
>>>>>>> Thanks,
>>>>>>>      Sascha
>>>>>>>
>>>>>>>
>>>>>>> P.S. Just in case, I put the hddm file with  "p eta pi0 pi0" events
>>>>>>> where i have observed the problem to  ~/public_html/debug.hddm
>>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>
>>
>>
>
>