PSCF v1.3
Features

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Features of PSCF programs are listed below, grouped so as to indicate the computational methods and programs to which they apply:

Features for both SCFT and PS-FTS (all programs):

  • Ability to treat mixtures containing any number of block polymer, homopolymer, and solvent molecular species
  • Ability to treat acyclic branched block polymers, as well as linear block polymers
  • Ability to use canonical, grand-canonical or mixed statistical ensembles
  • Thorough user and developer documentation provided via an integrated web manual
  • Well documented source code written in object-oriented C++
  • Example input files for many types of calculation
  • Python tools for data analysis and file processing

Features for SCFT (all programs):

  • Efficient Anderson-mixing SCFT iteration algorithms
  • Efficient "parameter sweeps": SCFT calculations for a sequence of states along a path in parameter space, with continuation of solutions

All features listed below are specific to the pscf_pc and pscf_pg programs. Both of these programs are designed for systems with periodic boundary conditions and can perform either SCFT or PS-FTS calculations. In SCFT, the periodic computational unit cell is usually chosen so as to represent a single crystallographic unit cell, whereas in FTS it may represent a larger region.

Features for SCFT or PS-FTS on periodic systems (pscf_pc and pscf_pg):

  • Choice of continuous thread or discrete bead-spring models of polymer chains
  • High accuracy pseudo-spectral solution of the modified diffusion equation for the continuous thread model.
  • Periodic unit cells with 1, 2 or 3 dimensional periodicity
  • Unit cells with all possible 2D and 3D Bravais lattice systems (i.e., cubic, orthorhombic, monoclinic, etc.)
  • A companion matlab package Polymer Visual for visualization of structures with periodic boundary conditions

Features for SCFT on periodic systems (pscf_pc and pscf_pg):

  • Efficient algorithms to find optimal unit cell parameters in SCFT
  • Imposition of any user-selected space-group symmetry on SCFT solutions
  • Built-in database of symmetry operations for all 230 3D space groups and 17 2D plane groups.
  • Inhomogeneous density constraint (a "mask")
  • External fields
  • Thin polymer films (implemented using a mask and external fields)

Features for PS-FTS with periodic boundary conditions (pscf_pc and pscf_pg):

  • Brownian dynamics (BD) and Monte Carlo (MC) sampling algorithms
  • BD algorithms: Leimkuhler-Matthews and predictor-corrector step algorithms
  • MC algorithms: real-space and "smart"/force-bias MC moves
  • Efficient algorithms for adjusting the pressure field so as to find a partial saddle-point (i.e., to impose incompressibility)
  • Tools for calculating free energy differences by thermodynamic integration, including the Einstein-crystal method
  • Parameter "ramps" in which one or more parameters change continuously during a simulation
  • Analysis tools to compute quantities of interest, including the structure factor, order parameters used to identify phase transitions, and derivatives of the Hamiltonian needed for thermodynamic integration calculations
  • Analysis tools can applied either during a simulation or by postprocessing of field trajectory files that are written during an earlier simulation


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