espressopp.interaction.ConstrainCOM¶
This class is for calculating forces acting on constrained center of mass of subchains [Zhang_2014].
Subchains are defined as a tuple list.
\[U = k_{com} \left(\vec{r_{com}} - \vec{R_{com}}\right)^2,\]
where \(\vec{r_{com}}\) stands for the center of mass of subchain and \(\vec{R_{com}}\) stands for the desired center of mass of subchain.
This class implies 2 conditions on a tuple list defining subchains:
- The length of all tuples must be the same.
- int(key particle id / The length of a tuple) must not be redundantly, where key particle id is the smallest particle id in a tuple.
| [Zhang_2014] | G. Zhang, L. A. Moreira, T. Stuehn, K. Ch. Daoulas, and K. Kremer, Equilibration of high molecular weight polymer melts: A hierarchical strategy, Macro Lett., 2014, 3, 198 |
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espressopp.interaction.ConstrainCOM(k_com)¶ Parameters: k_com (real) – (default: 100.)
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espressopp.interaction.FixedLocalTupleListConstrainCOM(system, tuplelist, potential)¶ Parameters: - system –
- tuplelist –
- potential –
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espressopp.interaction.FixedLocalTupleListConstrainCOM.getPotential()¶ Return type:
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espressopp.interaction.FixedLocalTupleListConstrainCOM.setCom(particlelist)¶ Parameters: particlelist –