[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: units.h

Ed,

I am using  CLHEP in my fitter at present, though I've considered 
switching to the equivalent Hall D calls (wrappers around the ROOT 
library). I originally chose it because it seemed much lighter weight 
than ROOT. On the other hand, we are pretty linked into ROOT now anyway 
(for good reasons).

Another thing I noticed more recently is that some of the vector-type 
stuff in ROOT was originally adopted from CLHEP in the first place.

The main problem with CLHEP for GlueX right now is that almost no one 
has it built on their computer. The build is relatively simple; I have 
it as part of my build_scripts[1]. It is supposed to be built on the 
JLab CUE, but I have not used that build personally. GEANT4 uses CLHEP, 
so I think we are all going to have it at some point anyway.

I did not know that it addresses the units issue. How?

  -- Mark

[1] http://www.jlab.org/Hall-D/software/wiki/index.php/Build_script_examples

Edward Brash wrote:
> Hi All,
>
> I know that I am not involved in GlueX at this point in time, but I am 
> still on the mailing list, and do following these discussions with 
> interest ...
>
> And, I don't want to throw a spanner in the works, as it were, but 
> have you all considered using the CLHEP package?  I think that it 
> might solve not only your units problem, but also provide you with a 
> lot of other functionality as well ...
>
> Cheers,
> Ed.
>
> On Dec 3, 2008, at 3:30 PM, Matthew Shepherd wrote:
>
>>
>> Here's the units.h file for CLEO.  Note that the unit choices are 
>> somewhat different from what Mark is proposing.  I'll let Mark 
>> multiply and divide by the requisite factors of 10 and put into the 
>> repository in an appropriate place.
>>
>> -Matt
>>
>>
>> #if !defined(EXPERIMENT_UNITS_H)
>> #define EXPERIMENT_UNITS_H
>> // -*- C++ -*-
>> //
>> // Package:     Cleo
>> // Module:      units.h
>> //
>> // Description: These are just a few definitions for specifying units 
>> and
>> //              keeping things consistent.
>> //
>> // Usage:
>> //    It's just like writing up homework!  Specify your units, and 
>> it'll all
>> //    work just dandy.  If a length is 3.5 cm, it becomes 3.5*k_cm.  
>> If it's
>> //    1.2 in, it becomes 1.2*k_in.
>> //
>> //    If, on the other hand, something passes a number back to you 
>> in, say,
>> //    grams per cubic centimeter, you would *divide* by k_g_per_cm3 
>> to get it
>> //    in the correct CLEO III units.  Think of the CLEO III units as
>> //    dimensionless, and this makes sense.
>> //
>> //    Simple, isn't it?
>> //
>> //    One final note:  "k_degrees" refers to angles, not 
>> temperature.  Since
>> //    there are no multiplicative conversions between the common 
>> temperature
>> //    units, this shouldn't cause much confusion.
>> //
>> // Author:      Michael Marsh
>> // Created:     Tue Jan 20 12:06:31 EST 1998
>> // $Id: units.h,v 1.6 2001/12/18 20:48:20 lkg Exp $
>> //
>> // Revision history
>> //
>> // $Log: units.h,v $
>> // Revision 1.6  2001/12/18 20:48:20  lkg
>> // added time units
>> //
>> // Revision 1.5  1998/11/24 19:35:49  mkl
>> // turned float into double for standard types and units
>> //
>> // Revision 1.4  1998/07/03 17:29:48  marsh
>> // Changed units of energy to GeV.  Added units for magnetic field (kG).
>> // Added more units, such as keV and radians, and more constants to 
>> convert
>> // from CLEO units to all units with constants.
>> //
>> // Revision 1.3  1998/05/14 19:58:05  marsh
>> // Added millimeters, microns, and mils.
>> //
>> // Revision 1.2  1998/05/07 22:26:06  marsh
>> // Renamed the constants to be more readable.  This was in response 
>> to input
>> // that people didn't like the old names, such as kM, which looked 
>> like it
>> // might be kilometers, but was in fact meters.
>> //
>> // Revision 1.1  1998/04/09 19:48:50  marsh
>> // New in repository.
>> //
>>
>> // system include files
>> #if defined(EXCEPTION_CLASH_WITH_MATH_H_BUG)
>> #define exception _math_bug_
>> #include <math.h>  // required for trigonometry and fabs
>> #undef exception
>> #else
>> #include <math.h>  // required for trigonometry and fabs
>> #endif
>>
>> // user include files
>>
>> const double k_in_to_cm = 2.54;
>>
>> const double k_m  = 1.0;
>> const double k_cm = 0.01;  // lengths are in meters
>> const double k_mm = 1.0E-3;
>> const double k_um = 1.0E-6; // microns
>> const double k_in = k_in_to_cm * k_cm;
>> const double k_mil = k_in * 1.0E-3;
>> const double k_to_m = 1/k_m;
>> const double k_to_cm = 1/k_cm;
>> const double k_to_mm = 1/k_mm;
>> const double k_to_um = 1/k_um;
>> const double k_to_in = 1/k_in;
>> const double k_to_mil = 1/k_mil;
>>
>> const double k_kg = 1.0;
>> const double k_g  = 0.001;
>> const double k_u  = 1.6605402E-27;
>> const double k_to_kg = 1/k_kg;
>> const double k_to_g = 1/k_g;
>> const double k_to_u = 1/k_u;
>>
>> const double k_kg_per_m3 = 1;
>> const double k_g_per_cm3 = 1000;  // density is in kg/m^3
>> const double k_to_kg_per_m3 = 1/k_kg_per_m3;
>> const double k_to_g_per_cm3 = 1/k_g_per_cm3;
>>
>> const double k_Pa  = 1; // pressure is in pascals
>> const double k_atm = 101325;
>> const double k_to_Pa = 1/k_Pa;
>> const double k_to_atm = 1/k_atm;
>>
>> const double k_GeV = 1; // energy is in GeV
>> const double k_MeV = 1.0E-3;
>> const double k_keV = 1.0E-6;
>> const double k_eV = 1.0E-9;
>> const double k_to_GeV = 1/k_GeV;
>> const double k_to_MeV = 1/k_MeV;
>> const double k_to_keV = 1/k_keV;
>> const double k_to_eV = 1/k_eV;
>> const double k_to_J = 1.60217733E-10;
>> const double k_J = 1/k_to_J;
>>
>> const double k_kGauss = 1;
>> const double k_Gauss = 1.0E-3;
>> const double k_Tesla = 10;
>> const double k_to_kGauss = 1/k_kGauss;
>> const double k_to_Gauss = 1/k_Gauss;
>> const double k_to_Tesla = 1/k_Tesla;
>>
>> const double k_radians = 1; // pretty much everything uses radians
>> const double k_degrees = M_PI / 180;
>> const double k_to_radians = 1/k_radians;
>> const double k_to_degrees = 1/k_degrees;
>>
>> const double k_psec = 1; // Cleo has typically used picoseconds
>> const double k_nsec = 1.0E3;
>> const double k_usec = 1.0E6;
>> const double k_msec = 1.0E9;
>> const double k_sec  = 1.0E12;
>> const double k_to_psec = 1/k_psec;
>> const double k_to_nsec = 1/k_nsec;
>> const double k_to_usec = 1/k_usec;
>> const double k_to_msec = 1/k_msec;
>> const double k_to_sec  = 1/k_sec;
>>
>> #endif /* EXPERIMENT_UNITS_H */
>>
>
> Dr. Edward J. Brash
> Department of Physics, Computer Science, and Engineering
> Christopher Newport University
> Newport News, VA, USA 23606.
> Telephone: (757) 753-2831 (cell)
> Telephone: (757) 269-7216 (JLab Office)
> Telephone: (757) 594-7451 (CNU Office)
> Fax:       (757) 594-7919
> Email:     brash@pcs.cnu.edu
>
>
>