[CP2K:9497] how to reduce the memory usage for HFX

[Xiaoming Wang]

Hi Dr. Ling,

Thanks for your suggestions which are really helpful. I did't expected that 
CP2K could handle so large systems, but it does. Actually, the calculation 
is not that slow. The only thing is the huge memory usage, that I need to 
use many nodes.

Best,
Xiaoming 

On Thursday, September 28, 2017 at 6:06:28 AM UTC-4, S Ling wrote:
>
> Hi
>
> This maybe the largest hybrid DFT calculation for a 3D periodic system 
> that I have ever heard of.
>
> You may also check whether you really need a CUTOFF_RADIUS of 10 A in 
> your PBE0-TC-LRC functional. The density matrix of insulators decays 
> exponentially with SQRT(E_gap)*r12 (see Eqn. 16 of this paper, 
> http://aip.scitation.org/doi/10.1063/1.2931945). For system with a 
> sizeable band gap, you can usually get converged electronic properties with 
> a cutoff radius of 6 A or even smaller. I would suggest you to check the 
> convergence of your target properties with respect to CUTOFF_RADIUS in 
> smaller cells, and then choose the CUTOFF_RADIUS that gives the best 
> balance of accuracy and cost for your calculation on the large supercell. A 
> smaller cutoff radius may help you to reduce the memory usage of the HFX 
> calculation.
>
> In addition, if you use OT algorithm for SCF, you can usually reduce the MAX_SCF 
> parameter in &SCF subsection to 20 or 30, in order to take advanrage of 
> the preconditioning. This will not reduce the memory usage, but it may help 
> to accelerate the SCF convergence. 
>
> SL
>
>
>
> On 27 September 2017 at 15:56, Xiaoming Wang <wxi... at gmail.com 
> <javascript:>> wrote:
>
>> Hi all,
>>
>> Is there any way to reduce the memory usage for HFX calculations? I am 
>> dealing with a large scale HFX calculation with the box size of 47*47*47 A 
>> and 22560 atoms. After testing, I find that 30Gb mem is required for each 
>> MPI task. I am using the MPI/Openmp version. Following is my input, any 
>> suggestion on the improvement of the parameters is appreciated. 
>>
>> &GLOBAL
>>   PROJECT_NAME mysys
>>   RUN_TYPE GEO_OPT
>>   PRINT_LEVEL MEDIUM
>> &END GLOBAL
>> &FORCE_EVAL
>>   METHOD QS
>>   &DFT
>>     CHARGE -1
>>     LSD
>>     BASIS_SET_FILE_NAME BASIS_MOLOPT
>>     BASIS_SET_FILE_NAME BASIS_ADMM_MOLOPT
>>     POTENTIAL_FILE_NAME GTH_POTENTIALS
>>     WFN_RESTART_FILE_NAME pbe.wfn
>>     &QS
>>      EPS_PGF_ORB 1.0e-32
>>     &END
>>     &MGRID
>>       CUTOFF 250
>>       REL_CUTOFF 50
>>     &END MGRID
>>     &XC
>>       &XC_FUNCTIONAL
>>        &PBE
>>         SCALE_X 0.75
>>         SCALE_C 1.0
>>        &END PBE
>>        &PBE_HOLE_T_C_LR
>>         CUTOFF_RADIUS 10.0
>>         SCALE_X 0.25
>>        &END PBE_HOLE_T_C_LR
>>       &END XC_FUNCTIONAL
>>       &HF
>>        FRACTION 0.25
>>        &SCREENING
>>         EPS_SCHWARZ 1.0e-6
>>        &END SCREENING
>>        &INTERACTION_POTENTIAL
>>         POTENTIAL_TYPE TRUNCATED
>>         CUTOFF_RADIUS 10.0
>>         T_C_G_DATA ./t_c_g.dat
>>        &END INTERACTION_POTENTIAL
>>        &MEMORY
>>         MAX_MEMORY 32000
>>         EPS_STORAGE_SCALING 0.1
>>        &END MEMORY
>>       &END HF
>>     &END XC
>>     &SCF
>>       MAX_SCF 100
>>       EPS_SCF 1.0e-6
>>       CHOLESKY INVERSE
>>       SCF_GUESS RESTART
>>       &OT
>>        ROTATION
>>        PRECONDITIONER FULL_KINETIC
>>        ENERGY_GAP 0.001
>>       &END OT
>>       &OUTER_SCF
>>        EPS_SCF 1.0e-6
>>        MAX_SCF 10
>>       &END OUTER_SCF
>>     &END SCF
>>     &PRINT
>>      &MULLIKEN OFF
>>      &END MULLIKEN
>>      &MO_CUBES
>>       WRITE_CUBE F
>>       NHOMO 2
>>      &END MO_CUBES
>>      &END PRINT
>>     &AUXILIARY_DENSITY_MATRIX_METHOD
>>      METHOD BASIS_PROJECTION
>>      ADMM_PURIFICATION_METHOD MO_DIAG
>>     &END AUXILIARY_DENSITY_MATRIX_METHOD
>>   &END DFT
>>   &SUBSYS
>>     &CELL
>>       ABC [angstrom] 47.216 47.216 47.216
>>       ALPHA_BETA_GAMMA [deg] 90 90 90
>>       PERIODIC XYZ
>>       SYMMETRY CUBIC
>>     &END CELL
>>     &TOPOLOGY
>>      COORD_FILE_FORMAT XYZ
>>      COORD_FILE_NAME el.xyz
>>     &END TOPOLOGY
>>     &KIND Cs
>>       ELEMENT Cs
>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>       AUX_FIT_BASIS_SET cFIT7
>>       POTENTIAL GTH-PBE-q9
>>     &END KIND
>>     &KIND Pb
>>       ELEMENT Pb
>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>       AUX_FIT_BASIS_SET cFIT6
>>       POTENTIAL GTH-PBE-q4
>>     &END KIND
>>     &KIND Br
>>       ELEMENT Br
>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>       AUX_FIT_BASIS_SET cFIT6
>>       POTENTIAL GTH-PBE-q7
>>     &END KIND
>>   &END SUBSYS
>> &END FORCE_EVAL
>> &MOTION
>>  &GEO_OPT
>>   MAX_ITER 500
>>   OPTIMIZER LBFGS
>>  &END GEO_OPT
>> &END MOTION
>>
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