Re: standard units in software

[Matthew Shepherd <mashephe@indiana.edu>]

Sorry, there's an (obvious) typo here:

Should be:

bool checkEnergy( double energy ){

return( energy > 30*k_MeV );
}

Eugene is right -- more CPU cycles and typing.  But I think  
readability and odds of making a mistake and introducing a bug are  
greatly reduced.

-Matt

On Nov 24, 2008, at 2:39 PM, Matthew Shepherd wrote:

>
> Hi Eugene,
>
> Other routines can use the same global constants.  For example:
>
> suppose showerEnergy is some energy expressed internally in an  
> object in standard units.  Then:
>
> if( checkEnergy( showerEnergy ) ){
> ...
> }
>
> bool checkEnergy( double energy ){
>
> return( energy*k_MeV > 30*k_MeV );
> }
>
> One just needs to be sure:
>
> #include "units.h"
>
> exists wherever the global constants need to be used.
>
> In other words, the numbers are always expressed in standard units.   
> Having the constants just helps alleviate keeping track of what the  
> units are.  If the standard units are MeV then k_MeV == 1, k_GeV ==  
> 0.001, etc..
>
> -Matt
>