[Ifeffit] odd feff6 behavior

[Carlo Segre]

Anatoly and Bruce:

What value would you recommend for nplx?

Carlo


On Fri, 10 Jun 2005, Anatoly Frenkel wrote:

> [Ifeffit] odd feff6 behaviorBruce,
>
> I checked that the same problem existed for the original FEFF601.f fortran
> file in UNIX. I looked for the string "np > np1x" and found that the code
> stops when this condition is true. np1x is a fixed parameter defined in the
> code as parameter (np1x = 12000). When np (the paths counter) becomes 12001
> (it is incremented in the code as the paths are counted), the code stops.
> Apparently, for this structure it happens for rmax exceeds 6.6 . When rmax =
> 6.6, the number of paths is less than 12000, and the code does not stop. I
> do not know why 12000 was chosen as a threshold... we can ask
> Alex.Therefore, if you have access to the feff6 source that is used in
> IFEFFIT (I assume you do), you can increase the np1x and recompile.
> Regards,
>
> Anatoly
>
> ******************
> Anatoly Frenkel, Ph.D.
> Associate Professor
> Physics Department
> Yeshiva University
> 245 Lexington Avenue
> New York, NY 10016
>
> (YU)  212-340-7827
> (BNL) 631-344-3013
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>
> anatoly.frenkel at yu.edu
> http://www.yu.edu/faculty/afrenkel
>
>
>  -----Original Message-----
>  From: ifeffit-bounces at millenia.cars.aps.anl.gov
> [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov]On Behalf Of Bruce Ravel
>  Sent: Friday, June 10, 2005 3:43 PM
>  To: XAFS Analysis using Ifeffit
>  Subject: [Ifeffit] odd feff6 behavior
>
>
>
>
>
>  Hi,
>
>  Here's a feff6 curiosity.  Take this atoms.inp file:
>
>    title = TiN
>    space = 225
>    a =       4.24173       b =       4.24173       c =       4.24173
>    core =  Ti      edge =  K       rmax =    7.0
>    atoms
>    ! elem   x          y          z
>      Ti    0.00000    0.00000    0.00000
>      N     0.50000    0.50000    0.50000
>
>
>
>  Run atoms, then run feff6l (the one that comes with Ifeffit, it's the only
>  version I've tried this with).  Feff ends with this error message:
>      Eliminating path degeneracies...
>         Plane wave chi amplitude filter   2.50%
>        np, np1x=    12001   12000
>      Fatal Error: at PATHSD: np > np1x
>
>  This message comes from pathsd.f, but I don't understand either the
> message or
>  the part of the code it comes from.  Does anyone else have a hint as to
> the
>  problem?
>
>  One more datum.  If you reduce rmax to 6.7 in the atoms.inp file, the
> problme
>  persists.  If you make rmax 6.6, feff6l is happy.
>
>  Thanks,
>  B
>
>
>
>  --
>   Bruce Ravel  ----------------------------------- bravel at anl.gov  -or-
>
> ravel at phys.washington.edu
>   Environmental Research Division, Building 203, Room E-165
>   Argonne National Laboratory                        phone: (1) 630 252
> 5033
>   Argonne IL 60439, USA                                fax: (1) 630 252
> 9793
>
>   My homepage:    http://feff.phys.washington.edu/~ravel
>   EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/
>
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-- 
Carlo U. Segre -- Professor of Physics
Associate Dean for Special Projects, Graduate College
Illinois Institute of Technology
Voice: 312.567.3498            Fax: 312.567.3494
Carlo.Segre at iit.edu    http://www.iit.edu/~segre