# fix particledistribution/discrete command

# fix particledistribution/discrete/massbased command

# fix particledistribution/discrete/numberbased command

## Syntax

    fix ID group-ID particledistribution/discrete seed ntemp t_id t_weight ...

- ID, group-ID are documented in fix command
- particledistribution/discrete or particledistribution/discrete/massbased or particledistribution/discrete/numberbased = style name of this fix command
- seed = random number generator seed (prime number greater 10000)
- ntemp = number of particle templates to be used in this command
- zero or more t_id/t_weight pairs are appended, number of pairs must match ntemp

    t_id = ID of a fix of type particletemplate/sphere
    t_weight = mass % or number % for this template in the distribution

## Examples

    fix pdd1 all particledistribution/discrete 123457  1 pts1 1.0
    fix pdd1 all particledistribution/discrete 17903  2 pts1 0.3 pts2 0.7

## Description

Define a discrete particle distribution that defines a discrete particle distribution to be inserted by a fix insert/stream, fix insert/pack, fix insert/rate/region or a related command. It takes several templates of type fix_particletemplate_sphere as input, which define the properties of the single particles (such as radius, density that are part of the distribution. The pairs of IDs and weights for the templates (t_id / t_weight) define the distribution. Please note that the number of pairs must match ntemp, but can be arbitrtarily large, so that any type of particle size distribution can be discretized.

For style particledistribution/discrete or particledistribution/discrete/massbased the weight of each template within the distribution is interpreted as mass-%, for style particledistribution/discrete/numberbased the weight is interpreted as number-%. Note that the sum of all weights must be equal to 1.0, if this is not the case the user is warned and the distribution is normalized automatically. Note that large particles are inserted first, so that a higher volume fraction can be achieved. If not all desired insertions could be performed, it is likely that the distribution is not accurately reproduced.

## Restart, fix_modify, output, run start/stop, minimize info

Information about the random state in this fix is written to binary restart files so you can restart a simulation with the same particles being chosen for insertion. None of the fix_modify options are relevant to this fix. No global scalar or vector or per-atom quantities are stored by this fix for access by various output commands. No parameter of this fix can be used with the start/stop keywords of the run command. This fix is not invoked during `energy minimization`.

## Restrictions

> none

## Related commands

fix insert/stream, fix insert/pack, fix insert/rate/region

Default: none