Re: [boost] 3j, 6j 9j symbol (was Special functions, Quaternions, Octonions)

From: boost (boost_at_[hidden])
Date: 2001-04-12 11:41:38

Salut,

On Thursday 12 April 2001 13:31, you wrote:
[...]
> > BTW: Looking at this package I wondered if someone is working
> >      on Clebsch-Gordon coefficients and 3j, 6j and 9j symbols?
>
> If these are easily computed, I may be able to use NTL very high accuracy
> to calculate then for 128-bit floating point use like math constants.
>
> Paul

It's just a terrible mess of +,-,*,/ and a few sqrts.
Most of the calculation can be done using integers,
but currently I only needed special 3j symbols for
which explicit formulas are known.
Please note that 3j symbols are not just number but real valued functions
taking 6 integer parameters,
e.g. ClebschGordon_3j( j1, m1, j2, m2, j3, m3) ; j_i>=0; abs(m_i) <= j_i
corresponding to the coupling of two angular moments to a third one.

Best wishes,
Peter