[CP2K-user] [CP2K:21605] CP2K calculation on a large system facing FFT error

Sayed Ahmad Almohri aalmohri at umich.edu
Tue Jul 1 23:01:22 UTC 2025


I have a bit of a long question, I am running a system which is a little 
bit large (19.175bx56x12.953, 624 atoms) and I faced an issue. When I ran 
it with my regular inputs I was getting this error:

*******************************************************************************
 *   ___                                                                   
    *
 *  /   \                                                                   
   *
 * [ABORT]                                                                 
    *
 *  \___/                     Index to radix array not found.               
   *
 *    |                                                                     
   *
 *  O/|                                                                     
   *
 * /| |                                                                     
   *
 * / \                                                     
 pw/fft_tools.F:270 *
 *******************************************************************************

I first assumed its an NGRID problem and used a higher value but that 
wasn't the fix, I looked up the error and on the forum I saw that we should 
use the EXTENDED_FFT_LENGTHS flag to fix this. I was able to run this with 
that flag. Then I did some testing on my previous runs to see how different 
the results could be with and without the flag. I took a system with box 
dimensions (19.175x24.899x19.954, 312 atoms) ran it once with 
EXTENDED_FFT_LENGTHS and once without and I see a difference of 0.15 
Hartree in the energy (without is lower); is there a way to fine tune the 
grid size without using EXTENDED_FFT_LENGTHS, since I am getting a lower 
value without EXTENDED_FFT_LENGTHS on ran on the same system my assumption 
if that its lowering accuracy.

Input file:
! CP2K Library file locations

@SET data_dir (not putting in message)

! Additional input block file locations

@SET cell_file incfg.box               
@SET crds_file incfg.xyz                 
@SET intg_file cp2k.md_int-block.inp    
@SET mdio_file cp2k.md_io-block.inp     
@SET qmps_file cp2k.qm_psuedo-block.inp 
@SET qmbs_file cp2k.qm_basis-block.inp  

! Specify the simualtion temperature

@SET temper 1000

!Note: 
!
! cell_file: Text file with cell vectors (cp2k format)
! crds_file: XYZ file with system coordinates (xyz format)
! intg_file: MD integrator specification, and energy I/O print frequency
! mdio_file: I/O file names/frequencies for MD (except energy!)
! qmps_file: QM Psuedo potential/dispersion/etc settings
! qmbs_file: QM basis sets for each atom type

&GLOBAL
    PROJECT                 ALD
    RUN_TYPE                MD
    PRINT_LEVEL             HIGH
    SEED                    1111
    PREFERRED_DIAG_LIBRARY  ELPA
    EXTENDED_FFT_LENGTHS    T
&END GLOBAL

&MOTION
    &MD
        @INCLUDE            ${intg_file}
        
         STEPS              0
         TIMESTEP           0.5
         TEMPERATURE        ${temper}  
    &END MD
    
    &CONSTRAINT
        &LAGRANGE_MULTIPLIERS OFF
            &END LAGRANGE_MULTIPLIERS
    &END CONSTRAINT

    &PRINT
        @INCLUDE            ${mdio_file}
    &END
&END MOTION


&FORCE_EVAL
   METHOD QS
   @INCLUDE                 ${qmps_file}
   
   &SUBSYS
      @INCLUDE              ${qmbs_file}
      &CELL
         @INCLUDE           ${cell_file}
         CELL_FILE_FORMAT   cp2k
         PERIODIC XYZ
      &END
      
      &TOPOLOGY
        COORD_FILE_NAME     ${crds_file}
        COORD_FILE_FORMAT   xyz
      &END TOPOLOGY
    &END SUBSYS

    STRESS_TENSOR ANALYTICAL

&END FORCE_EVAL

&EXT_RESTART
   #RESTART_FILE_NAME cp2k.restart
   #RESTART_DEFAULT F
   #RESTART_POS T
   #RESTART_VEL T
&END EXT_RESTART

psuedo potential block:
&DFT
   BASIS_SET_FILE_NAME ${data_dir}/GTH_BASIS_SETS
   POTENTIAL_FILE_NAME ${data_dir}/GTH_POTENTIALS
   
   ! Tell CP2K to stop printing so many damn files
   &PRINT
      &E_DENSITY_CUBE OFF  
      &END E_DENSITY_CUBE
      &EFIELD_CUBE OFF
      &END EFIELD_CUBE
      &V_HARTREE_CUBE OFF
      &END V_HARTREE_CUBE
      &TOT_DENSITY_CUBE OFF
      &END TOT_DENSITY_CUBE     
      &ELF_CUBE OFF
      &END ELF_CUBE
      &MO_CUBES OFF
      &END MO_CUBES
      &NEIGHBOR_LISTS OFF
      &END NEIGHBOR_LISTS
     
      
   &END PRINT
   
   &MGRID
      CUTOFF 1200
      COMMENSURATE
      NGRIDS 4
   &END
   
   &QS
     EPS_DEFAULT 1.0E-12
     EXTRAPOLATION ASPC
     EXTRAPOLATION_ORDER 6 
   &END QS
   
   &SCF
      
      # Smearing is not compatible with OT
      # If smearing is requested need diagonalization
      # OT allows for faster SCF than diagonalization, so only use smearing 
if required!
      # Doesn't work well for high T systems ... couldn't converge molten 
carbon at 6000 K even with 500 MOs within 200 SCF... 
      #&SMEAR
      #  ELECTRONIC_TEMPERATURE ${temper}
      #  METHOD FERMI_DIRAC
      #&END SMEAR
      #ADDED_MOS 100 # Required for smearing ... set to at least 20% of 
occupied orbitals, may need more (check for error messages from single 
point test jobs)
      
      EPS_SCF 1.0E-7
      SCF_GUESS RESTART
      MAX_SCF 200
      
      &OUTER_SCF
        EPS_SCF 1.0E-7
        MAX_SCF 20
      &END OUTER_SCF
      
      # OT is not compatible with Smearing
      
      &OT
         MINIMIZER DIIS
         PRECONDITIONER FULL_SINGLE_INVERSE
         N_DIIS 7
      &END OT
      
      # Use diagonalization if smearing requested
      #
      #&DIAGONALIZATION
      #  ALGORITHM DAVIDSON
      #&END DIAGONALIZATION
      
      &PRINT
        &RESTART ON
        &END RESTART

        &RESTART_HISTORY OFF
        &END RESTART_HISTORY
        
      &END PRINT 
   &END SCF
   
   &XC
   
      &XC_FUNCTIONAL PBE
      &END XC_FUNCTIONAL
   
        &XC_GRID
            #XC_DERIV NN10_SMOOTH
    XC_DERIV  SPLINE2_SMOOTH
            XC_SMOOTH_RHO NN10
        &END XC_GRID
   
      &VDW_POTENTIAL
         DISPERSION_FUNCTIONAL PAIR_POTENTIAL
         
         &PAIR_POTENTIAL
           &PRINT_DFTD OFF
           &END PRINT_DFTD
           TYPE DFTD3
           LONG_RANGE_CORRECTION .TRUE.
           PARAMETER_FILE_NAME ${data_dir}/dftd3.dat 
           REFERENCE_FUNCTIONAL PBE
           R_CUTOFF [angstrom] 10.0
           EPS_CN 1.0E-6
         &END PAIR_POTENTIAL
         
      &END VDW_POTENTIAL
      
   &END XC
&END

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/cp2k/b0c588ff-0f5a-49f4-aa6b-b7fcba751f68n%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20250701/c6f44f19/attachment.htm>


More information about the CP2K-user mailing list