ML_OUTBLOCK
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).
| 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 vasprun.xml and vaspout.h5 (see table below). If possible, please use VASP.6.4.3 or higher for production runs with potentially large file output. |
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.
| Warning: This tag will potentially override defaults and INCAR values of NBLOCK! NBLOCK will be automatically set to the maximum of ML_OUTBLOCK and NBLOCK. |
A comparison of the effects of NBLOCK and ML_OUTBLOCK on the output frequency of different files/properties is given in the following table:
| 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