[CPMD-list] An error while performing wavefunction optimization

[Juerg Hutter]

Hi

the maximal FFT grid is defined by the lists in fftchk.F.
If you want to have larger grids you have to change
those routines.
However, a grid of 10000 seems extremely large. The largest
grid in a real application I'm aware of had 1400 points
in one direction and about 200 in the others.
Your calculation would be extremly expensive and would
only run (if you also have enough memory) on the largest
computers available.

>From your input I would guess that you can reduce the box
size considerably and if you use
SYMMETRY
0
POISSON SOLVER TUCKERMAN
you can gain another factor of 2 in grid size. If the
calculation is still too big you might reduce the cutoff
a little bit (maybe 80 Rydberg gives already good results),
but this has to be tested.

regards

Juerg Hutter

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich           E-mail: hutter at pci.unizh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
----------------------------------------------------------


On Mon, 12 Feb 2007, Nagesh Babu Idupulapati wrote:

>
>
> Dear all,
>
> while Iam trying to perform wavefunction optimization, Iam getting the 
> following error. Iam using version 3.9.2. can someone help me with this??
>
> FUNCTION FFTCHK
> THE MINIMAL MESH SIZE IS LARGER THAN          2048  M=        10118
> ADD LARGER MESH VALUES IN FFTCHK
> STOPGM! STACK OF MAIN CALLS:
> STOPGM! CALL      NUMPW
>
>
> PROGRAM STOPS IN SUBROUTINE FFTCHK |
>
>
>
>
> MY INPUT FILE :
>
> &CPMD
>  OPTIMIZE WAVEFUNCTION
>  MAXSTEP
>  1000
>  LBFGS
>  CONVERGENCE ORBITALS
>  1.0E-7
>  LSD
> &END
>
> &SYSTEM
>  ANGSTROM
>  SYMMETRY
>  0
>  CELL
>  29.0  29.0  17.5  0  0  0
>  CUTOFF
>  100.0
>  CHARGE
>  1
> &END
>
> &ATOMS
>
> *C_MT_GIA_BLYP   KLEINMAN-BYLANDER
>   LMAX=P
>   19
>   0.00000000    0.00000000    0.00000000
>   1.42846103    0.00000000    0.00000000
>   2.03032221    1.28925825    0.00000000
>   1.23364248    2.41886471   -0.06194811
> -0.14331688    2.28064633   -0.11116520
>   3.51217619    1.53752524    0.08011939
> -1.02493803    3.47010791   -0.22800749
>   1.27140950   -2.47090258   -0.20965115
>   2.15844332   -3.55732775   -0.32460536
>   3.41599891   -3.02505487   -0.24084385
>   2.03200687   -1.30942995   -0.06464497
>   4.70699451   -3.74530014   -0.28126183
> -0.16548473   -2.47329864   -0.18775260
> -0.83835247   -1.23653134    0.01111541
> -2.69268601   -3.76854097   -1.95495105
> -5.85127343   -2.10025012   -1.21386489
> -6.89088106   -2.58581723   -2.21382603
> -6.79389128   -4.10602597   -2.28581857
> -7.02050640   -4.69686958   -0.89611407
>
> *O_MT_GIA_BLYP  KLEINMAN-BYLANDER
>   LMAX=P
>   13
>  4.32300302    0.74719957    0.44278736
>  3.83172693    2.76650779   -0.26880457
> -0.67667270    4.59318430   -0.20074963
> -2.34395632    3.14521835   -0.38622195
>  4.80165313   -4.91711141   -0.42872625
>  5.73816361   -2.92441660   -0.13392101
> -0.84841590   -3.53606273   -0.35349451
> -2.06437078   -1.12944256    0.14599864
> -2.86840376   -2.47649876   -1.93906892
> -4.96495518   -1.28296799   -1.57450474
> -8.20605607   -4.98019202   -0.57705144
> -6.00590370   -4.85924642   -0.16685763
> -5.88168607   -2.57276358    0.13547053
>
> *N_MT_GIA_BLYP KLEINMAN-BYLANDER
> LMAX=P
> 2
> -0.71889394    1.10272394   -0.07097345
>  3.33874707   -1.68648626   -0.08883895
> -6.68087105   -1.98744073   -3.51668561
>
> *Ca_SEMI_BLYP_GIA.psp KLEINMAN-BYLANDER
> LMAX=D LOC=S
> 1
> -2.99501843    0.83253917   -0.02974558
>
> *H_GIA_BLYP KLEINMAN-BYLANDER
> LMAX=S
> 1
> 1.66918773    3.39632409   -0.08428239
> 4.77373669    2.88894730   -0.17541479
> -2.82298183    3.97002717   -0.45945814
> 1.91681228   -4.59343693   -0.43208288
> 6.54999400   -3.42386696   -0.16102304
> 4.11541813   -1.08349989    0.07659912
> -1.72200116   -4.08145677   -2.30147356
> -3.54838628   -4.38776008   -2.16815968
> -2.45300063   -4.41708677   -1.08520403
> -7.88084422   -2.31702138   -1.84528535
> -5.87883223   -1.37659627   -3.45583528
> -7.50337294   -1.42708220   -3.68870002
> -7.55180871   -4.48696130   -2.97032498
> -5.80485827   -4.39092935   -2.64462597
> -7.84873442   -5.33302867   -1.44182166
> -3.65568914   -2.24669997   -1.42111693
> &END
>
> &DFT
>  NEWCODE
>  FUNCTIONAL BLYP
> &END
>
>
> Regards
>
> Nagesh.
>
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