ML_LFAST

ML_LFAST = [logical]
Default: ML_LFAST = .FALSE.

Description: This tag switches on the very fast execution mode for machine learning force fields.

This tag is only available in the development version of VASP.

To be able to use the method one has to retrain his force-field with:

ML_LFAST=.TRUE.
ML_ISTART=1
NSW=0

After obtaining a ML_FFN, that file has to be copied to ML_FF and the fast code is used specifying the following tags:

ML_LFAST=.TRUE.
ML_ISTART=2

The speedup of the fast method compared to the regular method is increasing with increasing number of local reference configurations.

It should be noted that in the fast version no Bayesian error estimation is available.

Since the calculation time of the fast version is of the same order of magnitude as the timing for the output of the molecular-dynamics results, we advise decreasing the output frequency for molecular dynamics. This is controlled by the tag ML_OUTBLOCK. By default, it writes out all molecular-dynamics results at every molecular-dynamics step. Additionally, the calculation and output of the pair-correlation function can be suppressed by setting ML_OUTPUT_MODE=0.

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