fix_modify AtC on_the_fly command — LAMMPS documentation

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# fix_modify AtC on_the_fly command

## Syntax

    fix_modify <AtC fixID> on_the_fly <bond|kernel> <on|off>

- AtC fixID = ID of fix atc instance

- on_the_fly = name of the AtC sub-command

- bond or kernel = specifies on-the-fly calculation of bond or kernel matrix elements

- on or off = activate or discontinue on-the-fly mode

## Examples

    fix_modify AtC on_the_fly bond on
    fix_modify AtC on_the_fly kernel
    fix_modify AtC on_the_fly kernel off

## Description

Overrides normal mode of pre-calculating and storing bond pair-to-node a nd kernel atom-to-node matrices. If activated, it will calculate elements of these matrices during repeated calls of field computations (i.e. “on-the-fly”) and not store them for future use. The on flag is optional - if omitted, on_the_fly will be activated for the specified matrix. Can be deactivated using the off flag.

## Restrictions

Must be used with fix atc hardy.

## Related AtC commands

- fix_modify AtC command overview

## Default

By default, on-the-fly calculation is not active (i.e. off). However, THE code does a memory allocation check to determine if it can store all needed bond and kernel matrix elements. If this allocation fails, on-the-fly will be activated.