mirror of https://github.com/lammps/lammps.git
124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
#include <stdio.h>
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#include <math.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdarg.h>
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#include <string.h>
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#define rc 5.50679// A
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#define h 0.50037// A
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#define E1 2.01458*1e2//eV
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#define E2 6.59288*1e-3//eV
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#define r01 0.83591//A
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#define r02 4.46867//A
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#define a1 2.97758//1/A
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#define a2 1.54927//1/A
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#define d 0.86225*1e-2//A
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#define rs1 2.24//A
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#define rs2 1.8//A
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#define rs3 1.2//A
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#define S1 4.//eV/A^4
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#define S2 40.//eV/A^4
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#define S3 1.15*1e3//eV/A^4
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#define a 3.80362
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#define r03 -2.19885//A
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#define r04 -2.61984*1e2//A
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#define b1 0.17394//A^-2
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#define b2 5.35661*1e2//1/A
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#define F0 -2.28235//eV
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#define F2 1.35535//eV
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#define q1 -1.27775//eV
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#define q2 -0.86074//eV
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#define q3 1.78804//eV
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#define q4 2.97571//eV
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#define Q1 0.4
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#define Q2 0.3
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#define EOK 0
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#define ERROR -1
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double M (double r, double r0, double alpha) {
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return exp (-2.*alpha*(r-r0)) - 2.*exp (-alpha*(r-r0));
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}
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double psi (double x) {
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if (x >= 0.) return 0.;
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else return pow (x, 4.) / (1.+pow (x, 4.) );
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}
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double H (double x) {
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if (x >= 0) return 1.;
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else return 0.;
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}
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double V (double r) {
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return ( E1*M(r,r01,a1) + E2*M(r,r02,a2) + d ) * psi ( (r-rc)/h ) -
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H (rs1-r)*S1*pow (rs1-r, 4.) -
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H (rs2-r)*S2*pow (rs2-r, 4.) -
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H (rs3-r)*S3*pow (rs3-r, 4.);
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}
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double rho (double r) {
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return ( a*exp (-b1*pow (r-r03, 2.)) + exp (-b2*(r-r04)) ) * psi ( (r-rc)/h );
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}
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double F (double rho_) {
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if (rho_ < 1.)
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return F0 + .5*F2*pow (rho_-1., 2.)
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+ q1*pow (rho_-1.,3.)
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+ q2*pow (rho_-1.,4.)
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+ q3*pow (rho_-1.,5.)
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+ q4*pow (rho_-1.,6.);
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else if (rho_ > 1.)
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return ( F0 + .5*F2*pow (rho_-1., 2.) + q1*pow (rho_-1., 3.) + Q1*pow (rho_-1., 4.)) /
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( 1. + Q2*pow (rho_-1., 3.) );
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else exit (ERROR);
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}
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int main (void) {
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int Nr = 10001;
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double rmax = 9.;
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double dr = rmax/(double)Nr;
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int Nrho = 10001;
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double rhomax = rho (0.);
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double drho = rhomax/(double)Nrho;
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int atomic_number = 1;
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double mass = 63.55;
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double lattice_constant = 3.615;
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char lattice_type[] = "FCC";
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int i;
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char LAMMPSFilename[] = "Cu_Mishin1.eam";
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FILE *LAMMPSFile = fopen (LAMMPSFilename, "w");
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if (!LAMMPSFile) exit (ERROR);
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// Header for setfl format
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fprintf (LAMMPSFile, \
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"#-> LAMMPS Potential File in DYNAMO 86 setfl Format <-#\n"\
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"# Mishin Cu EAM1 PRB(2001)63:224106\n"\
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"# Implemented by G. Ziegenhain (2007) gerolf@ziegenhain.com \n"\
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"%d Cu\n"\
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"%d %20.20f %d %20.20f %20.20f\n"\
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"%d %20.20f %20.20f %s\n",
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atomic_number,
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Nrho, drho, Nr, dr, rc,
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atomic_number, mass, lattice_constant, lattice_type);
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// Embedding function
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for (i = 0; i < Nrho; i++)
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fprintf (LAMMPSFile, "%20.20f\n", F ((double)i*drho));
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// Density function
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for (i = 0; i < Nr; i++)
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fprintf (LAMMPSFile, "%20.20f\n", rho ((double)i*dr));
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// Pair potential
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for (i = 0; i < Nr; i++)
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fprintf (LAMMPSFile, "%20.20f\n", V ((double)i*dr) * (double)i*dr);
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fclose (LAMMPSFile);
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return (EOK);
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}
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