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Description: Output distance in number of steps for molecular-dynamics simulations with machine-learned force fields in prediction-only mode ({{TAGO|ML_MODE|run}}).
Description: Output distance in number of steps for molecular-dynamics simulations with machine-learned force fields in prediction-only mode ({{TAGO|ML_MODE|run}}).
{{NB|important|This tag is only available as of VASP.6.4.0. Unfortunately, the implementation of this feature was incomplete before VASP.6.4.3. In {{VASP}} versions prior to 6.4.3 there was still substantial remaining per-time-step output, in particular in {{FILE|vasprun.xml}} and {{FILE|vaspout.h5}}. If possible, please use VASP.6.4.3 or higher for production runs with potentially large file output.}}
{{NB|important|This tag is only available as of VASP.6.4.0. Unfortunately, the implementation of this feature was incomplete before VASP.6.4.3. In {{VASP}} versions prior to 6.4.3 there was still substantial remaining per-time-step output, in particular in {{FILE|vasprun.xml}} and {{FILE|vaspout.h5}} (see table below). If possible, please use VASP.6.4.3 or higher for production runs with potentially large file output.}}
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By default {{VASP}} writes all results at every molecular-dynamics step ({{TAGO|ML_OUTBLOCK|1}}). However, this may become inefficient when running long trajectories in production runs with a machine-learned force field in prediction-only mode ({{TAGO|ML_MODE|run}}). This is particularly true if the force field supports the fast execution mode, i.e., refitting was performed with {{TAGO|ML_MODE|refit}}. Then, depending on the system size, writing output each time step may hinder performance, cause heavy I/O load and create unnecessary large files. In order to circumvent these problems {{TAGO|ML_OUTBLOCK|n}} instructs {{VASP}} to write screen and file output only every <code>n</code> time steps.
By default {{VASP}} writes all results at every molecular-dynamics step ({{TAGO|ML_OUTBLOCK|1}}). However, this may become inefficient when running long trajectories in production runs with a machine-learned force field in prediction-only mode ({{TAGO|ML_MODE|run}}). This is particularly true if the force field supports the fast execution mode, i.e., refitting was performed with {{TAGO|ML_MODE|refit}}. Then, depending on the system size, writing output each time step may hinder performance, cause heavy I/O load and create unnecessary large files. In order to circumvent these problems {{TAGO|ML_OUTBLOCK|n}} instructs {{VASP}} to write screen and file output only every <code>n</code> time steps.


In order to further increase the efficiency, calculation and output of pair-correlation functions can be completely switched off by setting {{TAGO|ML_OUTPUT_MODE|0}}. {{NB|warning|This tag will potentially override defaults and {{FILE|INCAR}} values of {{TAG|NBLOCK}}! {{TAG|NBLOCK}} will be automatically set to the maximum of {{TAG|ML_OUTBLOCK}} and {{TAG|NBLOCK}}.}}
In order to further increase the efficiency, calculation and output of pair-correlation functions can be completely switched off by setting {{TAGO|ML_OUTPUT_MODE|0}}. {{NB|warning|This tag will potentially override defaults and {{FILE|INCAR}} values of {{TAG|NBLOCK}}! {{TAG|NBLOCK}} will be automatically set to the maximum of {{TAG|ML_OUTBLOCK}} and {{TAG|NBLOCK}}.}} A comparison of the effects of {{TAG|NBLOCK}} and {{TAG|ML_OUTBLOCK}} on the output frequency of different files/properties is given in the following table:{{Table - Output interval options}}  


== Related tags and articles ==
== Related tags and articles ==

Revision as of 14:23, 27 March 2024

ML_OUTBLOCK = [integer]
Default: ML_OUTBLOCK = 1 

Description: Output distance in number of steps for molecular-dynamics simulations with machine-learned force fields in prediction-only mode (ML_MODE = run).


By default VASP writes all results at every molecular-dynamics step (ML_OUTBLOCK = 1). However, this may become inefficient when running long trajectories in production runs with a machine-learned force field in prediction-only mode (ML_MODE = run). This is particularly true if the force field supports the fast execution mode, i.e., refitting was performed with ML_MODE = refit. Then, depending on the system size, writing output each time step may hinder performance, cause heavy I/O load and create unnecessary large files. In order to circumvent these problems ML_OUTBLOCK = n instructs VASP to write screen and file output only every n time steps.

In order to further increase the efficiency, calculation and output of pair-correlation functions can be completely switched off by setting ML_OUTPUT_MODE = 0.

A comparison of the effects of NBLOCK and ML_OUTBLOCK on the output frequency of different files/properties is given in the following table:

INCAR tag controls output frequency: yes/no
Output file/property NBLOCK ML_OUTBLOCK
≤ 6.4.2 ≥ 6.4.3
screen output no yes yes
OSZICAR no yes yes
OUTCAR
  ↳ energies and time no no yes
  ↳ forces and stress yes yes yes
CONTCAR no yes yes
XDATCAR yes yes yes
PCDAT (1) yes yes yes
REPORT yes yes yes
ML_LOGFILE no yes yes
ML_HEAT no no yes
ML_EATOM no no yes
vasprun.xml
  ↳ energy no no yes
  ↳ forces (1) no no yes
  ↳ stress (1) no no yes
  ↳ structure (1) no no yes
  ↳ time no no yes
vaspout.h5
  ↳ energies no no(2) yes
  ↳ forces no no(2) yes
  ↳ stress no no(2) yes
  ↳ position_ions yes yes yes
  ↳ lattice_vectors yes yes yes
  ↳ ion_velocities yes yes yes
  ↳ pair_correlation (1) yes yes yes

(1) ML_OUTPUT_MODE = 0 can disable output completely

(2) Zeros are written for intermediate steps

Related tags and articles

ML_LMLFF, ML_MODE, ML_LFAST, ML_IERR, ML_OUTPUT_MODE, NBLOCK