Re: [boost] Re: Physical Quantities revisited

From: Matthias Troyer (troyer_at_[hidden])
Date: 2003-10-22 14:51:13

On Wednesday, October 22, 2003, at 08:51 PM, Paul A. Bristow wrote:
> I (and others) also expressed the prejudice that all are kept as their 
> base
> unit, now that 'everyone' is using at least 64-bit doubles in their 
> calculations
> (which is enough to keep everyone except the astronomers in the 
> exponent range.
> And the significand precision available (15-ish decimal digits) is 
> ample for all
> physical measurements.

I want to disagree here. I know particle physicists who use singe 
precision (float) numbers in some of their calculations. If instead of 
a common choice of units where hbar=1 one uses SI unites, where hbar is 
about about 1e-34, there will be problems. Even worse problems come 
when hbar^2 is needed.

Since for many calculations I do in quantum mechanics a natural set of 
units is where hbar, the speed of light, and the charge of the electron 
are set to one, I would not like to be forced to use SI units.

Matthias