manifold_gaussian_bump.h
bc5186bc30e1lammm-devel

manifold_gaussian_bump.h
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			/* ----------------------------------------------------------------------
			LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
			http://lammps.sandia.gov, Sandia National Laboratories
			Steve Plimpton, sjplimp@sandia.gov

			Copyright (2003) Sandia Corporation. Under the terms of Contract
			DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
			certain rights in this software. This software is distributed under
			the GNU General Public License.

			See the README file in the top-level LAMMPS directory.
			-----------------------------------------------------------------------

			This file is a part of the USER-MANIFOLD package.

			This package allows LAMMPS to perform MD simulations of particles
			constrained on a manifold (i.e., a 2D subspace of the 3D simulation
			box). It achieves this using the RATTLE constraint algorithm applied
			to single-particle constraint functions g(xi,yi,zi) = 0 and their
			derivative (i.e. the normal of the manifold) n = grad(g).

			It is very easy to add your own manifolds to the current zoo
			(we now have sphere, a dendritic spine approximation, a 2D plane (for
			testing purposes) and a wave-y plane.
			See the README file for more info.

			Stefan Paquay, spaquay@brandeis.edu
			Brandeis University, Waltham, MA, USA.

			This package was mainly developed at
			Applied Physics/Theory of Polymers and Soft Matter,
			Eindhoven University of Technology (TU/e), The Netherlands

			Thanks to Remy Kusters at TU/e for testing.

			This software is distributed under the GNU General Public License.

			------------------------------------------------------------------------- */

			#ifndef LMP_MANIFOLD_GAUSSIAN_BUMP_H
			#define LMP_MANIFOLD_GAUSSIAN_BUMP_H

			#include "manifold.h"

			namespace LAMMPS_NS {

			namespace user_manifold {

			// A Gaussian bump with a smoothed decay to flat 2D.
			class manifold_gaussian_bump : public manifold {
			public:
			enum { NPARAMS = 4 };
			manifold_gaussian_bump(class LAMMPS, int, char *);
			virtual ~manifold_gaussian_bump();

			virtual double g( const double * );
			virtual void n( const double , double );

			// Variant of g that computes n at the same time.
			virtual double g_and_n( const double x, double nn );

			static const char* type(){ return "gaussian_bump"; }
			virtual const char *id() { return type(); }

			virtual int nparams(){ return NPARAMS; }
			virtual void post_param_init();
			private:
			// Some private constants:
			double AA, ll, ll2, f_at_rc, fp_at_rc;
			double rc1, rc2, rc12, rc22, dr, inv_dr;

			// Stuff for the look-up table:
			double lut_x0, lut_x1;
			int lut_Nbins;
			double lut_dx;
			double *lut_z;
			double *lut_zp;

			double gaussian_bump ( double ) const;
			double gaussian_bump_x2 ( double ) const;
			double gaussian_bump_der( double ) const;

			void make_lut();
			double lut_get_z ( double rr ) const;
			double lut_get_zp( double rr ) const;
			void lut_get_z_and_zp( double rr, double &zz, double &zzp ) const;

			void test_lut();

			double taper( double );
			double taper_der( double );

			};
			}

			}


			#endif // LMP_MANIFOLD_GAUSSIAN_BUMP_H

lammps/src/USER-MANIFOLD/manifold_gaussian_bump.hbc5186bc30e1lammm-devel

manifold_gaussian_bump.hView Options

lammps/src/USER-MANIFOLD/manifold_gaussian_bump.h
bc5186bc30e1lammm-devel

manifold_gaussian_bump.h
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