Token SIGMA= of cast double

Fitting radius. This is read in the same way as in category STR.

RHOFIT ATOM=i LMXRHO=2 SIGMA=s(0,i) ... s(lmx,i)
       ATOM=j LMXRHO=2 SIGMA=s(0,j) ... s(lmx,j)
       ...

Where the s's are numbers. The value of LMXRHO is only an example.