units.h

[Matthew Shepherd <mashephe@indiana.edu>]

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 */