MD timings

[Anthony Reilly]

Hi all,

I am testing a setup for an NVT simulation of a reasonably large
system (768 atoms C H O) and was just wondering where the total time
for the MD step comes from as its quite a bit bigger than the OT DIIS
times put together. Just wanted to be sure this is normal. I am
running this with 32 processors on a Altix 4700 (4Gb ram per
processor). The CP2K version is from 17th of March (its compiled
[using intel compilers] by a sys admin so I can't update at will). I
can put up the full output in a .tar.gz if you want. I intend to add a
vdw correction (DFT + D) to this input but thought I get the QS bit
right first!

sample output:
Number of electrons:              2176


  Number of electrons:              2176
  Number of occupied orbitals:      1088
  Number of orbital functions:      7424

  Number of independent orbital functions:      7424

  Parameters for the always stable predictor-corrector (ASPC) method:

  ASPC order: 3

  B(1) =   3.000000
  B(2) =  -3.428571
  B(3) =   1.928571
  B(4) =  -0.571429
  B(5) =   0.071429

  Extrapolation method: ASPC


 SCF WAVEFUNCTION OPTIMIZATION

  Step  Update method              Time         Convergence
Total energy
 
-----------------------------------------------------------------------------

  ----------------------------------- OT
--------------------------------------

  Allowing for rotations:  F
  minimizer      : DIIS                : direct inversion
                                         in the iterative subspace
                            using      : -   7 diis vectors
                                         - safer DIIS on
  preconditioner : FULL_KINETIC        : cholesky inversion of T + eS
  stepsize       :    0.15000000
  energy_gap     :    0.20000000
  eps_taylor     :   0.10000E-15
  max_taylor     :             4

  ----------------------------------- OT
--------------------------------------
     1  OT DIIS        0.15E+00   23.27        0.0000114130
-3065.0344169969
     2  OT DIIS        0.15E+00   17.85        0.0000077033
-3065.0345462885

  *** SCF run converged in     2 steps ***


  Total electronic density (r-space):      -2175.9999999785
0.0000000215
  Total core charge density (r-space):      2176.0000000010
0.0000000010
  Total charge density (r-space):
0.0000000225
  Total charge density (g-space):
0.0000000225

  Overlap energy of the core charge distribution:
0.00016680388260
  Self energy of the core charge distribution:
-7327.55359090049751
  Core Hamiltonian energy:
2254.39113662662839
  Hartree energy:
2954.34446272070227
  Exchange-correlation energy:
-946.21672153922327

  Total energy:
-3065.03454628850795

 ENERGY| Total FORCE_EVAL ( QS ) energy (a.u.):
-3065.034656128970255


 
*******************************************************************************
 ENSEMBLE TYPE
=                                              nvt
 STEP NUMBER
=                                               16
 TIME [FS]
=                                         8.800000
 CONSERVED QNTY               =
-0.306469155441E+04

                                         INSTANTANEOUS        AVERAGES
 CPU [S]                      =
86.70                95.01
 {E-E0}/{k_b*N_at}            =          0.141442786080E+01
0.759416019145E+00
 POTENTIAL ENERGY[hartree]    =         -0.306503465613E+04
-0.306530346332E+04
 KINETIC ENERGY[hartree]      =          0.519811022030E+00
0.677701255551E+00
 TEMPERATURE[K]               =
142.671              186.007
 
*******************************************************************************

Input:
  METHOD Quickstep
  &DFT
    &MGRID
      CUTOFF 300
    &END MGRID
    &QS
       EPS_DEFAULT 1.0E-12
       EXTRAPOLATION ASPC
       EXTRAPOLATION_ORDER 3
    &END QS
    &SCF
      EPS_SCF 1.0E-5
      SCF_GUESS RESTART
      &OT
        MINIMIZER DIIS
        N_DIIS 7
      &END
   &PRINT
          &RESTART_HISTORY OFF
          &END
          &RESTART
             &EACH
                QS_SCF 0
                MD 10
             &END
             ADD_LAST NUMERIC
          &END
    &END
    &END SCF
 WFN_RESTART_FILE_NAME RESTART.wfn
    &XC
       &XC_GRID
          XC_DERIV SPLINE2
       &END XC_GRID
      &XC_FUNCTIONAL  PBE
      &END XC_FUNCTIONAL
    &END XC
  &END DFT
  &SUBSYS
    &CELL
      ABC 20.4842   24.0790   15.4756
      UNIT ANGSTROM
    &END CELL
    &KIND C
      BASIS_SET DZVP-GTH-PBE
      POTENTIAL GTH-PBE-q4
    &END KIND
    &KIND H
      BASIS_SET DZVP-GTH-PBE
      POTENTIAL GTH-PBE-q1
    &END KIND
     &KIND O
      BASIS_SET DZVP-GTH-PBE
      POTENTIAL GTH-PBE-q6
    &END KIND
   &TOPOLOGY
      COORD_FILE_FORMAT XYZ
      COORD_FILE_NAME benzo.xyz
 CONNECTIVITY OFF
   &END TOPOLOGY
  &END SUBSYS
&END FORCE_EVAL
&GLOBAL
  PROJECT Ph2CO2
  PRINT_LEVEL LOW
  RUN_TYPE MD
&END GLOBAL
&MOTION
&MD
COMVEL_TOL 0.000001
     ENSEMBLE NVT
    STEPS 20
    TIMESTEP 0.55
    TEMPERATURE 293.0
    &THERMOSTAT
    &NOSE
      LENGTH 5
      YOSHIDA 3
      TIMECON 4.0
      MTS 2
    &END NOSE
   &END
&END MD
&PRINT
    &TRAJECTORY
      &EACH
         MD 1
      &END
    &END
    &VELOCITIES ON
    &END
    &RESTART
      &EACH
         MD 10
      &END
    &END
    &RESTART_HISTORY OFF
    &END
  &END
&END MOTION