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Generating Electric-Field Schedules with gen_eregime

This tutorial reflects the current ReaxKit generator workflow for creating eregime.in files.

What eregime.in contains

eregime.in stores sampled electric-field rows with this structure:

(iteration, V_index, direction, magnitude)

with header:

#Electric field regimes
#start #V direction Magnitude(V/A)

Main command

The general format for this command is as follows:

reaxkit gen_eregime --type <sin|pulse|func> --iteration-step <int> [profile-specific flags]

Common flags: - --output output filename/path (default eregime.in) - --direction field axis (x, y, z) - --V voltage index column - --start-iter first iteration number

Profile 1: Sinusoidal field

reaxkit gen_eregime --type sin --output eregime.in --max-magnitude 0.004 --step-angle 0.05 --iteration-step 500 --num-cycles 2 --direction z --V 1

Meaning: - --max-magnitude: peak amplitude (about +0.004 to -0.004 V/A around offset) - --step-angle: angular sampling density (smaller = denser sampling) - --iteration-step: MD iterations between consecutive rows - --num-cycles: number of sine cycles

Optional sin-only controls: - --phase - --dc-offset

Profile 2: Smooth pulse field

reaxkit gen_eregime --type pulse --output eregime.in --amplitude 0.003 --width 50 --period 200 --slope 20 --iteration-step 250 --num-cycles 5 --direction z --V 1

Meaning: - --amplitude: pulse height above baseline - --width: flat-top duration - --period: full positive+negative cycle length - --slope: rise/fall duration - --num-cycles: cycle count

Optional pulse controls: - --step-size (sampling resolution) - --baseline

Profile 3: User-defined function

reaxkit gen_eregime --type func --output eregime.in --expr "0.003*cos(2*pi*t/100)" --t-end 1000 --dt 1 --iteration-step 250 --direction z --V 1

Meaning: - --expr: function of t - --t-end: final sampled time - --dt: sampling interval - --iteration-step: iteration mapping between samples

Validation behavior

The generator validates inputs before writing: - direction must be x, y, or z - iteration_step must be positive - profile-specific required flags must be provided - pulse constraints must be physically consistent

Invalid settings raise clear errors instead of producing malformed files.

Python API note

If you need programmatic generation, the core API is:

from reaxkit.engine.reaxff.generators.eregime_generator import gen_eregime

with profile_type="sin" | "pulse" | "func" and the same profile parameters.

Output location

Generated inputs are stored using ReaxKit generator output layout (under reaxkit_workspace/inputs/), with optional --copy-to-dot to place a copy in the current working directory.

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