http://www.atm.ox.ac.uk/user/wells/voigt.html
Voigt function calculation
R.J. Wells Rapid Approximation to the Voigt/Faddeeva Function and its Derivatives (Postscript File, 0.6 Mb) JQSRT 62 (1999), pp 29-48.
Abstract:
Existing algorithms for the evaluation of the Voigt/Faddeva function are
adapted to produce a method which is more efficient for atmospheric
line-by-line calculations. The approach allows greater computational speed
to be achieved if the maximum relative error criteria can be relaxed.
A supplementary algorithim to calculate partial derivatives of the Voigt
function simmultaneously with the Faddeva function is also specified.
Corrigenda: Appendix A.
This only affects the code used when R=4 and calculation of L is not required (fastest_humlik.for).
The comment in the code
"For speed the following 3 lines should replace the 3 above if R=4 and L is not required ..."
is wrong.
Corrected code for this case (only) is
provided
which has also been modified to give improved performance when used with
large y values (as found in the low wavenumber data in the HITRAN database).
Fortran77 source code by ftp
- Anonymous ftp to ftp.atm.ox.ac.uk cd pub/user/wells/voigt
- File humdev.for. Subroutine HUMDEV to calculate K, L and derivatives of K.
- File humlik.for. Subroutine HUMLIK to calculate both K and L.
- File fast_humlik.for. Subroutine HUMLIK to calculate K only.
- File fastest_humlik.for. Best HUMLIK subroutine to calculate K (only) to relative accuracy of 10-4.
Note this code was modified on 27th April, 2000 and 3rd August, 2000.
Any comments on this web page should be addressed to
wells@atm.ox.ac.uk