**Syntax:**

boundary x y z

pis periodicnis non-periodic

**Examples:**

boundary p p n

**Description:**

Set the periodicity of the global domain in each of the x,y,z dimensions. "N" means the domain is non-periodic in that dimension, so that if particles move outside the domain, they are lost. "P" means the domain is periodic in that dimension, so particles wrap-around to the other size and can react with nearby particles across the periodic boundary.

**Restrictions:** none

**Related commands:**

**Default:**

All dimensions are periodic.