It is possible to configure a Lattice for the 3D space, which can be useful to speed up the computation of the potentials. Note though, that this goes in hand with a loss of accuracy: If the lattice is applied, the evaluation of the potentials is carried out only on the nodes of the lattice. Intermediate values are interpolated.
The configuration of a lattice is usually not necessary, it is however required if the Thermodynamic VTK Output (see Thermodynamics VTK Output), the Thermodynamic Lattice Output (see Thermodynamics Lattice Output ) or the Potentials_Affect_Thresholds option is enabled.
The following parameters are only required, if the Lattice section is used in the configuration file. Otherwise, no lattice will be used at all.

Sizes (array<double,3>, optional, default depends on modus):
Sizes of lattice in x, y, z directions in fm.

Cell_Number (array<int,3>, optional, default depends on modus):
Number of cells in x, y, z directions.

Origin (array<double,3>, optional, default depends on modus):
Coordinates of the left, down, near corner of the lattice in fm.

Periodic (bool, optional, default true for Box modus, false for other modi):
Use periodic continuation or not. With periodic continuation x + i * lx is equivalent to x, same for y, z.

Potentials_Affect_Thresholds (bool, optional, default = false):
Include potential effects, since mean field potentials change the threshold energies of the actions.

For information on the format of the lattice output see Thermodynamics VTK Output or Thermodynamics Lattice Output. To configure the thermodynamic output, see Output Configuration.

Examples: Configuring the Lattice

The following example configures the lattice with the origin in (0,0,0), 20 cells of 10 fm size in each direction and with periodic boundary conditions. The potential effects on the thresholds are taken into consideration. Note that, as the origin is by definition the left down near corner of the cell, center is located at (5, 5, 5).

Lattice:
    Origin:    [0.0, 0.0, 0.0]
    Sizes:    [10.0, 10.0, 10.0]
    Cell_Number:    [20, 20, 20]
    Periodic: True
    Potentials_Affect_Thresholds: True

In case of Collider, Box, and Sphere modus (see input_general_ for choosing modus) there is also an option to set up lattice automatically. For example, for Collider modus

Lattice:

sets up a lattice that (heuristically) covers causally allowed particle positions until the end time of the simulation (see input_general_ for choosing end time). The lattice may also be automatically contracted in z direction depending on the chosen way of density calculation.

Another example for Box modus:

Lattice:
    Cell_Number:    [20, 20, 20]

sets up a periodic lattice that matches box sizes.