[CP2K-user] needs advice to speed up hybrid/ADMM method

Sun Geng gengs... at gmail.com
Sun Sep 13 21:11:33 UTC 2020


Hi,
Thank you for your prompt reply.
For the basis set, I am using the small (DZVP) primary basis sets and small 
auxiliary basis set too. I planned to increase them if  the accuracy is not 
optimal.
Indeed, my target system has a large band gap (~3eV). However, I would like 
to study the band gap of the material, can I use OT method? it seems that 
OT method only prints the energies of occupied orbitals. Please correct me 
if I am wrong.

Finally, I would assume the line (printing the Number of sph. ERI's 
calculated on the fly is not zero) only works for the first SCF iteration? 
and How could I have a good estimation on the MAX_MEMORY? 
and will the MAX_MEMORY depend on the choice of OMP_NUM_THREAD?

Thank you very much.
Best Regards,
Geng



在2020年9月13日星期日 UTC-7 下午12:15:40<n... at berkeley.edu> 写道:

> You pointed out a key issue at the end of your post. "ERI's calculated on 
> the fly" should ideally be zero. The reason is that the 4-center 
> electron-repulsion integrals (ERIs) are geometric objects, and only need to 
> be evaluated in the first SCF, provided you can store their results in 
> memory. If you have enough memory for this, then the first SCF step will be 
> long, but the subsequent SCF steps will be only slightly more expensive 
> than a GGA calculation. 
>
> Other than that there are two things I might note:
> (1) If your system has a band-gap, you should use the OT method instead of 
> standard matrix diagonalization, it scales quite well and has very nice 
> convergence behavior.
> (2) You say you have 120Gb of memory available for you calculation, but 
> only 13Gb are consumed by your HFX module. Even with the rest of the cp2k 
> program taking some memory, you should have a lot more memory left over for 
> storing thee ERIs. Double check MAX_MEMORY is a reasonable value, it is the 
> max amount of memory for *each* MPI task to use.
> (3) Last thing that could be an issue is your auxiliary basis set, which 
> ones are you using for this calculation? ADMM is so beneficial because you 
> can use a smaller, aux basis, for the HF part of the calculation, but maybe 
> your are using a large aux basis set? 
>
> In general, ADMM calc should be much faster than the same calc in vasp 
> using a primary basis set, so long as you don't make thee supercell too big.
> On Sunday, September 13, 2020 at 11:42:55 AM UTC-7 ge... at gmail.com 
> wrote:
>
>> Dear CP2K users, 
>>
>> I would like benchmark  a small periodic system (11 A x 11 A x 11A)  
>> using HSE06 functional  with results obtained from VASP,
>> Here is my input for DFT section:
>>
>>    &DFT
>>       BASIS_SET_FILE_NAME BASIS_MOLOPT_UCL
>>       BASIS_SET_FILE_NAME BASIS_MOLOPT
>>       BASIS_SET_FILE_NAME BASIS_ADMM_MOLOPT
>>       BASIS_SET_FILE_NAME BASIS_ADMM
>>       POTENTIAL_FILE_NAME GTH_POTENTIALS
>>       WFN_RESTART_FILE_NAME cp2k-RESTART.wfn
>>       &MGRID
>>          CUTOFF 320
>>          COMMENSURATE
>>       &END MGRID
>>       &QS
>>          EXTRAPOLATION PS
>>          EXTRAPOLATION_ORDER 3
>>          EPS_DEFAULT  1.0E-11
>>          EPS_PGF_ORB  1.0E-14
>>          MAP_CONSISTENT T
>>       &END QS
>>       &SCF
>>          SCF_GUESS RESTART
>>          EPS_SCF 1.0E-7
>>          MAX_SCF 300
>>          ADDED_MOS 100
>>          &DIAGONALIZATION
>>             ALGORITHM STANDARD
>>          &END DIAGONALIZATION
>>          &SMEAR  ON
>>             METHOD FERMI_DIRAC
>>             ELECTRONIC_TEMPERATURE [K] 300
>>          &END SMEAR
>>          &MIXING
>>             METHOD BROYDEN_MIXING
>>             ALPHA 0.2
>>             BETA 1.5
>>             NBROYDEN 8
>>          &END MIXING
>>       &END SCF
>>       !&XC
>>       !   &XC_FUNCTIONAL PBE
>>       !   &END XC_FUNCTIONAL
>>       !&END XC
>>       &XC
>>         &XC_FUNCTIONAL
>>           &PBE
>>             SCALE_X 0.0
>>             SCALE_C 1.0
>>           &END PBE
>>           &XWPBE
>>             SCALE_X -0.25
>>             SCALE_X0 1.0
>>             OMEGA 0.11
>>           &END XWPBE
>>         &END XC_FUNCTIONAL
>>         &HF
>>           &SCREENING
>>             EPS_SCHWARZ 1.0E-6
>>             SCREEN_ON_INITIAL_P T
>>           &END SCREENING
>>           &INTERACTION_POTENTIAL
>>             POTENTIAL_TYPE SHORTRANGE
>>             OMEGA 0.11
>>           &END INTERACTION_POTENTIAL
>>           &MEMORY
>>             MAX_MEMORY  4000
>>             EPS_STORAGE_SCALING 0.1
>>           &END MEMORY
>>           FRACTION 0.25
>>         &END HF
>>       &END XC
>>       &AUXILIARY_DENSITY_MATRIX_METHOD
>>           METHOD BASIS_PROJECTION
>>           ADMM_PURIFICATION_METHOD NONE
>>       &END AUXILIARY_DENSITY_MATRIX_METHOD
>>       &PRINT
>>          &PDOS
>>             FILENAME pdos
>>             # print all projected DOS available:
>>             NLUMO -1
>>             # split the density by quantum number:
>>             COMPONENTS
>>          &END
>>       &END PRINT
>>    &END DFT
>>
>> The calculation restarted from a converged PBE wavefunction.
>> However, I found that the calculation is quite "slow" ( Vasp needs 240 
>> seconds for a SCF step, but CP2K needs almost 2400 seconds. Both of them 
>> are carried out using a computing node with 24 cores and 120 G memory in 
>> total). I understand it is not easy to compare the different software 
>> because of very different setups, but I wound expect the ADMM method in 
>> CP2K should be much faster.
>>
>> Below is the output.
>>
>>  SCF WAVEFUNCTION OPTIMIZATION
>>
>>   Step     Update method      Time    Convergence         Total energy    
>> Change
>>   
>> ------------------------------------------------------------------------------
>>
>>   HFX_MEM_INFO| Est. max. program size before HFX [MiB]:                  
>>    792
>>
>>  *** WARNING in hfx_types.F:1287 :: Periodic Hartree Fock calculation    
>>   ***
>>  *** requested with use of a truncated or shortrange potential. The 
>> cutoff ***
>>  *** radius is larger than half the minimal cell dimension. This may 
>> lead  ***
>>  *** to unphysical total energies. Reduce the cutoff radius in order to  
>>   ***
>>  *** avoid possible problems.                                            
>>   ***
>>
>>   HFX_MEM_INFO| Number of cart. primitive ERI's calculated:      
>>  11992558561508
>>   HFX_MEM_INFO| Number of sph. ERI's calculated:                    
>> 157558545566
>>   HFX_MEM_INFO| Number of sph. ERI's stored in-core:                
>>  16901607068
>>   HFX_MEM_INFO| Number of sph. ERI's stored on disk:                      
>>      0
>>   HFX_MEM_INFO| Number of sph. ERI's calculated on the fly:          
>> 91978901962
>>   HFX_MEM_INFO| Total memory consumption ERI's RAM [MiB]:                
>>   13711
>>   HFX_MEM_INFO| Whereof max-vals [MiB]:                                  
>>     454
>>   HFX_MEM_INFO| Total compression factor ERI's RAM:                      
>>    9.41
>>   HFX_MEM_INFO| Total memory consumption ERI's disk [MiB]:                
>>      0
>>   HFX_MEM_INFO| Total compression factor ERI's disk:                      
>>   0.00
>>   HFX_MEM_INFO| Size of density/Fock matrix [MiB]:                        
>>     24
>>   HFX_MEM_INFO| Size of buffers [MiB]:                                    
>>     90
>>   HFX_MEM_INFO| Number of periodic image cells considered:                
>>    123
>>   HFX_MEM_INFO| Est. max. program size after HFX  [MiB]:                  
>>   3582
>>
>>      1 NoMix/Diag. 0.20E+00 6553.7     0.12989389     -3154.6382899197 
>> -3.15E+03
>>
>>  *** WARNING in hfx_types.F:1287 :: Periodic Hartree Fock calculation    
>>   ***
>>  *** requested with use of a truncated or shortrange potential. The 
>> cutoff ***
>>  *** radius is larger than half the minimal cell dimension. This may 
>> lead  ***
>>  *** to unphysical total energies. Reduce the cutoff radius in order to  
>>   ***
>>  *** avoid possible problems.                                            
>>   ***
>>
>>      2 Broy./Diag. 0.20E+00 2486.1     0.00624233     -3159.6346919624 
>> -5.00E+00
>>
>>  *** WARNING in hfx_types.F:1287 :: Periodic Hartree Fock calculation    
>>   ***
>>  *** requested with use of a truncated or shortrange potential. The 
>> cutoff ***
>>
>>
>> Is there anything wrong with my input that slows down the calculation?
>> In particular, the " ERI's calculated on the fly" is not zero which seems 
>> not good according to a slide from "
>> https://mattatlincoln.github.io/talks/GhentWorkshop/?print-pdf#/"
>>
>> Thank you very much in advance
>> Best Regards,
>> Geng
>>
>>
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