[CPMD-list] EWALD SUM not equal in real and Q-space

[Juerg Hutter]

Hi

I still can't reproduce your problem. However, as you sent
me a binary pseudopotential I was not able to use it.
I replaced it by another pp and the charge densities were
accurate to machine precision both in real and G space.
There are now two possibilities:
1) the problem is connected to your pp 
   -> please send the input files to the atomic code
2) the problem is connected to your computer/compiler/os etc.
   -> try the input on another type of computer

Juerg

PS: send mails also to the mailing list. There might be
    other people interested in this problem, or people
    that can help.

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 1 635 4491
Physical Chemistry Institute   FAX   : ++41 1 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
----------------------------------------------------------


On Sun, 11 Aug 2002, Shiwu Gao wrote:

> Dear Juerg,
> 
> Attached please find a test case, where I still have probem.  
> For smaller systems (than this one), there is no such problems. 
> In the tar.gz file you also find the output and uspp that 
> I use. Please let me what you find and where the problem 
> is. 
> 
> Many thanks again,
> 
> Shiwu 
> 
> PS 
> 
> For you information:
> 
> The test case is a 2-layer slab model of Pt(111) surface in 
> p(3x3) 2-D symmetry, and the calculation was done my laptop 
> with RedHat Linux 7.2 as OS.
> 
> 
> Juerg Hutter wrote:
> > 
> > Hi
> > 
> > I can't reproduce this problem. Could you post an input
> > for a system (as small as possible) where this error
> > occurs?
> > 
> > Juerg
> > 
> > ----------------------------------------------------------
> > Juerg Hutter                   Phone : ++41 1 635 4491
> > Physical Chemistry Institute   FAX   : ++41 1 635 6838
> > University of Zurich           E-mail: hutter at pci.unizh.ch
> > Winterthurerstrasse 190
> > CH-8057 Zurich, Switzerland
> > ----------------------------------------------------------
> > 
> > On Fri, 9 Aug 2002, Shiwu Gao wrote:
> > 
> > > Hi,
> > >
> > > I got a trouble in running CPMD with the Vanderbildt uspp,
> > > which I generated myself. The program stops and complains that
> > > the Ewald sum does not equal in real and Fourier Q-space,
> > >
> > > Typical error message looks like this
> > >
> > >   ****************************************************************
> > >
> > >  CPU TIME FOR WAVEFUNCTION INITIALIZATION:           8.73 SECONDS
> > >  ***    RWFOPT| THE NEW SIZE OF THE PROGRAM IS   13844 kBYTES ***
> > >  EWALD SUM IN REAL SPACE OVER  5* 5* 5 CELLS
> > > IN FOURIER SPACE:                               360.000005713858
> > > IN REAL SPACE:                                  359.999999999984
> > >
> > >  *****************************************************************
> > >
> > > Note the charge should be 360 in this case. Tested many uspp's including
> > > the potential included in the latest uspp package. All have the same
> > > problem. Note that the sum in real space is usually OK with an error
> > > less than 10^-10, while the error in Q-space is large, 10^-5--10^-6.
> > >
> > > Has anybody met this problem with uspp? What is the way out of it?
> > >
> > > Thanks in advance,
> > >
> > > Shiwu Gao
> > > _______________________________________________
> > > CPMD-list mailing list
> > > CPMD-list at cpmd.org
> > > http://www.cpmd.org/mailman/listinfo/cpmd-list
> > >
> > 
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