FitProcess
This page gives hints on how to fit the anharmonic part of a model in multibinit.
Introduction¶
The fit process implemented in multibinit is based on [Escorihuela-Sayalero2017]. The fit process of multibinit contains two main options:
- Generate the list of symmetry-adapted terms
- Select the best coefficients in the list with the fit process
In the first option, multibinit will generate a set of coefficients only if fit_generateCoeff is set to one. This generation is mainly parametrized by fit_rangePower and fit_cutoff. You can avoid the generation by providing a list of coefficients with the model_anharmonic.XML file (see multibinit help file).
Then, the fit process will select the coefficients one by one up to fit_ncoeff according to the procedure details in [Escorihuela-Sayalero2017]. This process requires to provide the training_set_HIST.nc list file (see multibinit help file)
Tutorials¶
The First lesson on Multibinit explains how to build a lattice model and to run a dynamics.
Related Input Variables¶
basic:
- fit_SPCoupling FIT anharmonic Strain-Phonon COUPLING coefficients
- fit_anhaStrain FIT ANHARmonic STRAIN coefficients
- fit_coeff FIT anharmonic COEFFficients
- fit_cutoff FIT CUT-OFF of the anharmonic phonon interaction
- fit_generateCoeff FIT GENERATE anharmonic COEFFicient
- fit_initializeData FIT INITIALIZE DATA for the fit
- fit_ncoeff FIT Number of COEFFicients
- fit_rangePower FIT RANGE POWER for the coefficients
- fit_tolMSDE FIT TOLerance on Mean Standard Deviation of the Energy
- fit_tolMSDF FIT TOLerance on Mean Standard Deviation of the Forces
- fit_tolMSDFS FIT TOLerance on Mean Standard Deviation of the Forces and Stresses
- fit_tolMSDS FIT TOLerance on Mean Standard Deviation of the Stresses
useful:
- ts_option FIT Training Set OPTION
expert:
- fit_bancoeff FIT BANed COEFFicients
- fit_fixcoeff FIT FIXed COEFFicients
- fit_nbancoeff FIT Number of BANed COEFFicients
- fit_nfixcoeff FIT Number of FIXed COEFFicients
- opt_coeff OPTimize Cofficients
- opt_effpot OPTimize EFFective POTential
- opt_ncoeff OPTimize NUMBER of COEFFicients
Selected Input Files¶
paral:
v8: