n_max

This keyword sets the number of radial ($n_{\max }^{\mathrm{R}}$) and angular ($n_{\max }^{\mathrm{A}}$) descriptor components as introduced in Sect. II.B and Eq. (2) of [Fan2022b]. The syntax is:

n_max <n_max_R> <n_max_A>

where n_max_R and n_max_A are $n_{\max }^{\mathrm{R}}$ and $n_{\max }^{\mathrm{A}}$, respectively. The two parameters must satisfy $0\le n_{\max }^{\mathrm{R}},n_{\max }^{\mathrm{A}}\le 19$.

The default values of $n_{\max }^{\mathrm{R}}=4$ and $n_{\max }^{\mathrm{A}}=4$ are relatively small but typically yield high speed.

Note: These parameters should not be confused with $N_{\mathrm{bas}}^{\mathrm{R}}$ and $N_{\mathrm{bas}}^{\mathrm{A}}$, which are set via the basis_size keyword.