ML MRB1

ML_MRB1 = [integer]
Default: ML_MRB1 = 8 

Description: This tag sets the number $N_\text{R}^0$ of radial basis functions used to expand the radial descriptor $\rho^{(2)}_i(r)$ within the machine learning force field method.

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The radial descriptor is constructed from

$\rho_{i}^{(2)}\left(r\right) = \frac{1}{4\pi} \int \rho_{i}\left(r\hat{\mathbf{r}}\right) d\hat{\mathbf{r}}, \quad \text{where} \quad \rho_{i}\left(\mathbf{r}\right) = \sum\limits_{j=1}^{N_{\mathrm{a}}} f_{\mathrm{cut}}\left(r_{ij}\right) g\left(\mathbf{r}-\mathbf{r}_{ij}\right)$

and $g\left(\mathbf{r}\right)$ is an approximation of the delta function. In practice, the continuous function above is transformed into a discrete set of numbers by expanding it into a set of radial basis functions $\chi_{nl}(r)$ (see this section for more details):

$\rho_{i}^{(2)}\left(r\right) = \frac{1}{\sqrt{4\pi}} \sum\limits_{n=1}^{N^{0}_{\mathrm{R}}} c_{n00}^{i} \chi_{nl}\left(r\right).$

The tag ML_MRB1 sets the number $N_\text{R}^0$ of radial basis functions to use in this expansion. The value of ML_MRB1 is the default value for ML_MRB2.

Related Tags and Sections

ML_LMLFF, ML_MRB2, ML_W1, ML_RCUT1, ML_SION1

Examples that use this tag

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