posic.c

   1 /*
   2  * posic.c - precipitation process of silicon carbide in silicon
   3  *
   4  * author: Frank Zirkelbach <frank.zirkelbach@physik.uni-augsburg.de>
   5  *
   6  */
   7
   8 #include <math.h>
   9
  10 #include "moldyn.h"
  11 #include "math/math.h"
  12 #include "init/init.h"
  13 #include "visual/visual.h"
  14
  15 #include "posic.h"
  16
  17 int main(int argc,char **argv) {
  18
  19         t_moldyn md;
  20
  21         t_atom *si;
  22
  23         t_visual vis;
  24
  25         t_random random;
  26
  27         int a,b,c;
  28         double t,e,u;
  29         double help;
  30         t_3dvec p;
  31         int count;
  32
  33         t_lj_params lj;
  34
  35         char fb[32]="saves/lj_test";
  36
  37         /* init */
  38
  39         rand_init(&random,NULL,1);
  40         random.status|=RAND_STAT_VERBOSE;
  41
  42         /* testing random numbers */
  43         //for(a=0;a<1000000;a++)
  44         //      printf("%f %f\n",rand_get_gauss(&random),
  45         //                       rand_get_gauss(&random));
  46
  47         visual_init(&vis,fb);
  48
  49         a=LEN_X;
  50         b=LEN_Y;
  51         c=LEN_Z;
  52
  53         /* set for 'bounding atoms' */
  54         //vis.dim.x=a*LC_SI;
  55         //vis.dim.y=b*LC_SI;
  56         //vis.dim.z=c*LC_SI;
  57
  58         t=TEMPERATURE;
  59
  60         printf("placing silicon atoms ... ");
  61         count=create_lattice(DIAMOND,SI,M_SI,LC_SI,a,b,c,&si);
  62         printf("(%d) ok!\n",count);
  63
  64         /* testing purpose
  65         count=2;
  66         si=malloc(2*sizeof(t_atom));
  67         si[0].r.x=0.16e-9;
  68         si[0].r.y=0;
  69         si[0].r.z=0;
  70         si[0].element=SI;
  71         si[0].mass=M_SI;
  72         si[1].r.x=-0.16e-9;
  73         si[1].r.y=0;
  74         si[1].r.z=0;
  75         si[1].element=SI;
  76         si[1].mass=M_SI;
  77         */
  78
  79         printf("setting thermal fluctuations\n");
  80         thermal_init(si,&random,count,t);
  81         //v3_zero(&(si[0].v));
  82         //v3_zero(&(si[1].v));
  83
  84         /* check kinetic energy */
  85
  86         e=get_e_kin(si,count);
  87         printf("kinetic energy: %.40f [J]\n",e);
  88         printf("3/2 N k T = %.40f [J]\n",1.5*count*K_BOLTZMANN*t);
  89
  90         /* check total momentum */
  91         p=get_total_p(si,count);
  92         printf("total momentum: %.30f [Ns]\n",v3_norm(&p));
  93
  94         /* check potential energy */
  95         md.count=count;
  96         md.atom=si;
  97         md.potential=potential_lennard_jones;
  98         md.force=force_lennard_jones;
  99         md.cutoff=R_CUTOFF;
 100         md.cutoff_square=(R_CUTOFF*R_CUTOFF);
 101         md.pot_params=&lj;
 102         md.integrate=velocity_verlet;
 103         md.time_steps=RUNS;
 104         md.tau=TAU;
 105         md.status=0;
 106         md.visual=&vis;
 107         md.write=WRITE_FILE;
 108
 109         lj.sigma6=LJ_SIGMA_SI*LJ_SIGMA_SI;
 110         help=lj.sigma6*lj.sigma6;
 111         lj.sigma6*=help;
 112         lj.sigma12=lj.sigma6*lj.sigma6;
 113         lj.epsilon=LJ_EPSILON_SI;
 114
 115         u=get_e_pot(&md);
 116
 117         printf("potential energy: %.40f [J]\n",u);
 118         printf("total energy (1): %.40f [J]\n",e+u);
 119         printf("total energy (2): %.40f [J]\n",get_total_energy(&md));
 120
 121         md.dim.x=a*LC_SI;
 122         md.dim.y=b*LC_SI;
 123         md.dim.z=c*LC_SI;
 124
 125         printf("estimated accurate time step: %.30f [s]\n",
 126                estimate_time_step(&md,3.0,t));
 127
 128
 129         /*
 130          * let's do the actual md algorithm now
 131          *
 132          * integration of newtons equations
 133          */
 134
 135         moldyn_integrate(&md);
 136
 137         printf("total energy (after integration): %.40f [J]\n",
 138                get_total_energy(&md));
 139
 140         /* close */
 141
 142         visual_tini(&vis);
 143
 144         rand_close(&random);
 145
 146         return 0;
 147 }
 148