xnn.ffnn.models.reaxff.taper_up#

xnn.ffnn.models.reaxff.taper_up(x, rmin, rmax)[source]#

Ascending bond-order taper: 0 below rmin, 1 above rmax.

The cubic switching polynomial applied to the raw bond-order exponentials, with the regularized denominator (rmin - rmax)^3 + 1e-7 under which published ReaxFF-nn parameter libraries were trained – for the tiny bond-order thresholds this taper is applied to, the constant dominates the cube, so it acts as a near-step at rmin rather than a smooth switch.

Parameters:

x (Tensor) – Values to taper (bond orders).
rmin (float) – Lower and upper edge of the switching window.
rmax (float) – Lower and upper edge of the switching window.

Returns:

Taper values.

Return type:

Tensor