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#include<stdio.h> |
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#include<math.h> |
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#include<stdlib.h> |
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#define max_sites 15000 |
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#define MYSEED 8973247 |
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int nsites, xlat, ylat; |
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double beta; |
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double theta[max_sites], x[max_sites], y[max_sites], z[max_sites], phi[max_sites], mu[max_sites]; |
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double domsizex, domsizey; |
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double magx, magy, magz, magmag, kz, ktheta, strength, z0, theta0; |
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double en,dtheta,deltaz,deltaphi; |
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int attemp, nacc; |
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int main() |
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{ |
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void getmag(); |
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double eneri(double xi, double yi, double zi, double phii, double thetai, int i, int jb); |
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double toterg(); |
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void adjust(); |
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void mcmove(); |
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void store(FILE *outFile); |
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double twopi, nnd, myran, kb; |
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double ent; |
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int icycl, ncycl, imove, nmoves, nsamp; |
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int nx, ny, which, i, j; |
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FILE *outFile; |
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outFile=fopen("dp_file","w"); |
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srand48(MYSEED); |
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// These two parameters set the size of the system: |
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nnd = 7.0; |
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ny = 100; |
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// we want the domains to be roughly square: |
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nx = (int) ((double)ny / sqrt(3.0)); |
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// periodic box boundaries: |
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domsizex = sqrt(3.0) * nx * nnd; |
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domsizey = ny * nnd; |
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strength = 10.0; |
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ncycl = 1e7; |
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nmoves = 100; |
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nsamp = 1e4; |
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twopi = 2.0 * M_PI; |
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dtheta = 0.1; |
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kb = 0.0019872198; |
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beta = 1.0 / (kb * 300.0); |
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z0 = 0.0; |
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deltaz = 0.1; |
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deltaphi = 0.1; |
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kz = kb; |
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ktheta = kb; |
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theta0 = M_PI / 2.0; |
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which = 0; |
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xlat = 0; |
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for(i=0; i < nx; i++) { |
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xlat = xlat + 2; |
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ylat = 0; |
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for(j=0; j<ny; j++) { |
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which = which + 1; |
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x[which] = i * sqrt(3.0) * nnd; |
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y[which] = j * nnd; |
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myran = drand48(); |
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phi[which] = myran * twopi; |
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myran = drand48(); |
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theta[which] = acos(2.0*myran-1.0); |
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myran = drand48(); |
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z[which]=z0 + (2.0*myran-1.0)*deltaz; |
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mu[which] = strength; |
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which = which + 1; |
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printf("%d\n", which); |
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x[which] = nnd* sqrt(3.0) * (2.0*i + 1.0) / 2.0; |
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y[which] = nnd* ( 2.0*j+1.0 ) / 2.0; |
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myran = drand48(); |
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phi[which] = myran * twopi; |
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myran = drand48(); |
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theta[which] = acos(2.0*myran-1.0); |
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myran = drand48(); |
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z[which] = z0 + (2.0*myran-1.0) * deltaz; |
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mu[which] = strength; |
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ylat = ylat + 2; |
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} |
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} |
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nsites= which; |
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en=toterg(); |
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printf("\nthe initial energy is : \t%f\n\n",en); |
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attemp = 0; |
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nacc = 0; |
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adjust(); |
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for(icycl=1;icycl<=ncycl;icycl++) |
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{ |
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for(imove=1;imove<=nmoves;imove++) |
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{ |
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mcmove(); |
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} |
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if((icycl%nsamp) == 0) |
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{ |
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store(outFile); |
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getmag(); |
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printf("mag=%f\t%f\t%f\t%f\n", magx, magy, magz, magmag); |
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} |
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if( (icycl%(ncycl/5))==0 ) |
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{ |
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printf("\n=====> Done\t%d\tout of\t%d\n", icycl, ncycl); |
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adjust(); |
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} |
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} |
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if(ncycl!=0) |
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{ |
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if(attemp!=0) |
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{ |
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printf("Number of att. to disl. a part. :%d\nsuccess: %d(=%f%)\n\n", attemp, nacc, 100*(double)(nacc)/(double)(attemp)); |
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} |
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ent=toterg(); |
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if(fabs(ent-en)>1e-6) printf("\n###### PROBLEMS ENERGY ###############\n"); |
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printf("\nTotal energy end of simulation : %f\nrunning energy : %f\ndifference : %f\n\n", ent, en, ent-en); |
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} |
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fclose(outFile); |
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return 0; |
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} |
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double toterg() |
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{ |
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double eneri(double, double, double, double, double, int, int); |
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double xi, yi, zi, phii, thetai, eni; |
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int i, jb; |
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double ener=0.0; |
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for(i=1;i<=nsites;i++) |
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{ |
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xi = x[i]; |
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yi = y[i]; |
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zi = z[i]; |
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phii = phi[i]; |
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thetai = theta[i]; |
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jb = i; |
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eni=eneri(xi, yi, zi, phii, thetai, i, jb); |
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ener = ener + eni; |
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} |
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return ener; |
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} |
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void getmag( ) |
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{ |
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double thetai, phii; |
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int i; |
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magx = 0.0; |
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magy = 0.0; |
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magz = 0.0; |
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for(i=1;i<=nsites;i++) |
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{ |
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phii = phi[i]; |
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thetai = theta[i]; |
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magx = magx + mu[i] * cos(phii) * sin(thetai); |
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magy = magy + mu[i] * sin(phii) * sin(thetai); |
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magz = magz + mu[i] * cos(thetai); |
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} |
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magx = magx / (double)(nsites); |
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magy = magy / (double)(nsites); |
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magz = magz / (double)(nsites); |
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magmag = sqrt (magx*magx+magy*magy+magz*magz); |
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} |
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double eneri(double xi, double yi, double zi, double phii, double thetai, int i, int jb) |
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{ |
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double uxi, uyi, uzi, dx, dy, dz, r, r2, r3, r5, uxj, uyj, uzj, rcut; |
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double udotu, rdotui, rdotuj, vij, pre, vint; |
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double eni; |
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int j; |
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pre = 14.38362; |
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rcut = 30.0; |
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eni = 0.0; |
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uxi = mu[i] * cos(phii) * sin(thetai); |
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uyi = mu[i] * sin(phii) * sin(thetai); |
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uzi = mu[i] * cos(thetai); |
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for(j=jb;j<=nsites;j++) |
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{ |
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if(j!=i) |
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{ |
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dx = x[j]-xi; |
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if(fabs(dx)>(domsizex/2.0)) dx = dx - domsizex*copysign(1.0,dx)*(double)(int)(fabs(dx /domsizex)+0.5); |
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dy = y[j]-yi; |
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if(fabs(dy)>(domsizey/2.0)) dy = dy - domsizey*copysign(1.0,dy)*(double)(int)(fabs(dy /domsizey)+0.5); |
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dz = z[j]-zi; |
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r2 = dx*dx+dy*dy+dz*dz; |
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r = sqrt(r2); |
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if(r<rcut) |
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{ |
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r3 = r2*r; |
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r5 = r2*r3; |
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uxj = mu[j]*cos(phi[j]) * sin(theta[j]); |
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uyj = mu[j]*sin(phi[j]) * sin(theta[j]); |
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uzj = mu[j] * cos(theta[j]); |
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udotu = uxi*uxj + uyi*uyj + uzi*uzj; |
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rdotui = dx*uxi + dy*uyi + dz*uzi; |
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rdotuj = dx*uxj + dy*uyj + dz*uzj; |
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vij = pre*(udotu/r3 - 3.0*rdotui*rdotuj/r5); |
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eni = eni + vij; |
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} |
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} |
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} |
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vint = 0.5 * kz * (zi-z0) * (zi-z0) + 0.5 * ktheta * (thetai-theta0) * (thetai-theta0); |
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eni = eni + vint; |
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return eni; |
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} |
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void adjust() |
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{ |
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static int attempp, naccp; |
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double dzo, dphio, dthetao, frac; |
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if((attemp==0)||(attempp>=attemp)) |
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{ |
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naccp = nacc; |
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attempp = attemp; |
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} |
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else |
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{ |
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frac = (double)(nacc-naccp)/(double)(attemp-attempp); |
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dthetao = dtheta; |
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dzo = deltaz; |
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dphio = deltaphi; |
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dtheta = dtheta * fabs(frac/0.5); |
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deltaz = deltaz * fabs(frac/0.5); |
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deltaphi = deltaphi * fabs(frac/0.5); |
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if((dtheta/dthetao)>1.5) dtheta = dthetao*1.5; |
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if((dtheta/dthetao)<0.5) dtheta = dthetao*0.5; |
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if((deltaz/dzo)>1.5) deltaz = dzo * 1.5; |
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if((deltaz/dzo)<0.5) deltaz = dzo * 0.5; |
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if((deltaphi/dphio)>1.5) deltaphi = dphio * 1.5; |
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if((deltaphi/dphio)<0.5) deltaphi = dphio * 0.5; |
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printf("Max. displ. set to :%f\t%f\t%f\t(old :%f\t%f\t%f)\nFrac. acc.:%f\nattempts:%d\nsucces:%d\n\n", deltaz, deltaphi, dtheta, dzo, dphio, dthetao, frac, attemp-attempp, nacc - naccp); |
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naccp = nacc; |
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attempp=attemp; |
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} |
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} |
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void mcmove() |
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{ |
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int o; |
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double eno, zn, phin, thetan, enn, myran; |
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int jb; |
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attemp = attemp + 1; |
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jb = 1; |
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myran = drand48(); |
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o = (int)(nsites*myran) + 1; |
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eno=eneri(x[o], y[o], z[o], phi[o], theta[o], o, jb); |
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myran = drand48(); |
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zn = z[o] + (2.0*myran-1.0) * deltaz; |
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myran = drand48(); |
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phin = phi[o] + (2.0*myran-1.0) * deltaphi; |
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myran = drand48(); |
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thetan = theta[o] + (2.0*myran-1.0)*dtheta; |
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enn=eneri(x[o], y[o], zn, phin, thetan, o, jb); |
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myran = drand48(); |
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if(myran<=(exp(-beta*(enn-eno)))) |
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{ |
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nacc = nacc + 1; |
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en = en + (enn-eno); |
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z[o] = zn; |
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phi[o] = phin; |
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theta[o] = thetan; |
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} |
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} |
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void store(FILE* outFile) |
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{ |
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double uxi, uyi, uzi; |
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int i; |
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fprintf(outFile,"%d\n",nsites); |
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fprintf(outFile,"%d\t%d\n",xlat, ylat); |
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for(i=1;i<=nsites;i++) |
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{ |
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uxi = cos(phi[i])*sin(theta[i]); |
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uyi = sin(phi[i])*sin(theta[i]); |
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uzi = cos(theta[i]); |
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fprintf(outFile,"%s\t%f\t%f\t%f\t%f\t%f\t%f\t%f\n","Ar",x[i],y[i],z[i],phi[i],uxi,uyi,uzi); |
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} |
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} |
