fix shardlow command¶
+Syntax¶
+fix ID group-ID shardlow
+-
+
- ID, group-ID are documented in fix command +
- shardlow = style name of this fix command +
Examples¶
+fix 1 all shardlow
+Description¶
+Specifies that the Shardlow splitting algorithm (SSA) is to be used to
+integrate the DPD equations of motion. The SSA splits the integration
+into a stochastic and deterministic integration step. The fix
+shardlow performs the stochastic integration step and must be used
+in conjunction with a deterministic integrator (e.g. fix nve or fix nph). The stochastic
+integration of the dissipative and random forces is performed prior to
+the deterministic integration of the conservative force. Further
+details regarding the method are provided in (Lisal) and
+(Larentzos).
The fix shardlow must be used with the pair_style dpd/fdt or pair_style dpd/fdt/energy command to properly initialize the +fluctuation-dissipation theorem parameter(s) sigma (and kappa, if +necessary).
+Note that numerous variants of DPD can be specified by choosing an +appropriate combination of the integrator and pair_style dpd/fdt command. DPD under isothermal conditions can +be specified by using fix shardlow, fix nve and pair_style +dpd/fdt. DPD under isoenergetic conditions can be specified by +using fix shardlow, fix nve and pair_style dpd/fdt/energy. DPD +under isobaric conditions can be specified by using fix shardlow, fix +nph and pair_style dpd/fdt. DPD under isoenthalpic conditions can +be specified by using fix shardlow, fix nph and pair_style +dpd/fdt/energy. Examples of each DPD variant are provided in the +examples/USER/dpd directory.
++
Restrictions¶
+This fix is only available if LAMMPS is built with the USER-DPD +package. See the Making LAMMPS section +for more info.
+This fix is currently limited to orthogonal simulation cell +geometries.
+This fix must be used with an additional fix that specifies time +integration, e.g. fix nve or fix nph.
+The Shardlow splitting algorithm requires the sizes of the sub-domain +lengths to be larger than twice the cutoff+skin. Generally, the +domain decomposition is dependant on the number of processors +requested.
+