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43 #include "gmxcomplex.h"
46 #include "gmx_fatal.h"
57 t_complex *tab_xy, *tab_qxyz;
62 /* TODO: fix thread-safety */
64 /* the other routines are in complex.h */
65 static t_complex conjmul(t_complex a,t_complex b)
69 c.re = a.re*b.re + a.im*b.im;
70 c.im = a.im*b.re - a.re*b.im;
78 static void tabulate_eir(int natom,rvec x[],int kmax,cvec **eir,rvec lll)
83 printf("Go away! kmax = %d\n",kmax);
87 for(i=0; (i<natom); i++) {
88 for(m=0; (m<3); m++) {
93 for(m=0; (m<3); m++) {
94 eir[1][i][m].re = cos(x[i][m]*lll[m]);
95 eir[1][i][m].im = sin(x[i][m]*lll[m]);
97 for(j=2; (j<kmax); j++)
99 eir[j][i][m] = cmul(eir[j-1][i][m],eir[1][i][m]);
103 void init_ewald_tab(ewald_tab_t *et, const t_commrec *cr, const t_inputrec *ir,
110 fprintf(fp,"Will do ordinary reciprocal space Ewald sum.\n");
112 (*et)->nx = ir->nkx+1;
113 (*et)->ny = ir->nky+1;
114 (*et)->nz = ir->nkz+1;
115 (*et)->kmax = max((*et)->nx,max((*et)->ny,(*et)->nz));
117 (*et)->tab_xy = NULL;
118 (*et)->tab_qxyz = NULL;
123 real do_ewald(FILE *log, gmx_bool bVerbose,
126 real chargeA[], real chargeB[],
128 t_commrec *cr, int natoms,
129 matrix lrvir, real ewaldcoeff,
130 real lambda, real *dvdlambda,
133 real factor=-1.0/(4*ewaldcoeff*ewaldcoeff);
134 real scaleRecip =4.0*M_PI/(box[XX]*box[YY]*box[ZZ])*ONE_4PI_EPS0/ir->epsilon_r; /* 1/(Vol*e0) */
135 real *charge,energy_AB[2],energy;
137 int lowiy,lowiz,ix,iy,iz,n,q;
138 real tmp,cs,ss,ak,akv,mx,my,mz,m2,scale;
139 gmx_bool bFreeEnergy;
145 gmx_fatal(FARGS,"No parallel Ewald. Use PME instead.\n");
150 if (!et->eir) /* allocate if we need to */
152 snew(et->eir,et->kmax);
153 for(n=0;n<et->kmax;n++)
154 snew(et->eir[n],natoms);
155 snew(et->tab_xy,natoms);
156 snew(et->tab_qxyz,natoms);
159 bFreeEnergy = (ir->efep != efepNO);
164 /* make tables for the structure factor parts */
165 tabulate_eir(natoms,x,et->kmax,et->eir,lll);
167 for(q=0; q<(bFreeEnergy ? 2 : 1); q++) {
173 scale = 1.0 - lambda;
181 for(ix=0;ix<et->nx;ix++) {
183 for(iy=lowiy;iy<et->ny;iy++) {
186 for(n=0;n<natoms;n++)
187 et->tab_xy[n]=cmul(et->eir[ix][n][XX],et->eir[iy][n][YY]);
189 for(n=0;n<natoms;n++)
190 et->tab_xy[n]=conjmul(et->eir[ix][n][XX],et->eir[-iy][n][YY]);
191 for(iz=lowiz;iz<et->nz;iz++) {
193 m2=mx*mx+my*my+mz*mz;
194 ak=exp(m2*factor)/m2;
195 akv=2.0*ak*(1.0/m2-factor);
197 for(n=0;n<natoms;n++)
198 et->tab_qxyz[n]=rcmul(charge[n],cmul(et->tab_xy[n],
199 et->eir[iz][n][ZZ]));
201 for(n=0;n<natoms;n++)
202 et->tab_qxyz[n]=rcmul(charge[n],conjmul(et->tab_xy[n],
203 et->eir[-iz][n][ZZ]));
206 for(n=0;n<natoms;n++) {
207 cs+=et->tab_qxyz[n].re;
208 ss+=et->tab_qxyz[n].im;
210 energy_AB[q]+=ak*(cs*cs+ss*ss);
211 tmp=scale*akv*(cs*cs+ss*ss);
212 lrvir[XX][XX]-=tmp*mx*mx;
213 lrvir[XX][YY]-=tmp*mx*my;
214 lrvir[XX][ZZ]-=tmp*mx*mz;
215 lrvir[YY][YY]-=tmp*my*my;
216 lrvir[YY][ZZ]-=tmp*my*mz;
217 lrvir[ZZ][ZZ]-=tmp*mz*mz;
218 for(n=0;n<natoms;n++) {
219 /*tmp=scale*ak*(cs*tab_qxyz[n].im-ss*tab_qxyz[n].re);*/
220 tmp=scale*ak*(cs*et->tab_qxyz[n].im-ss*et->tab_qxyz[n].re);
221 f[n][XX]+=tmp*mx*2*scaleRecip;
222 f[n][YY]+=tmp*my*2*scaleRecip;
223 f[n][ZZ]+=tmp*mz*2*scaleRecip;
238 energy = energy_AB[0];
240 energy = (1.0 - lambda)*energy_AB[0] + lambda*energy_AB[1];
241 *dvdlambda += scaleRecip*(energy_AB[1] - energy_AB[0]);
244 lrvir[XX][XX]=-0.5*scaleRecip*(lrvir[XX][XX]+energy);
245 lrvir[XX][YY]=-0.5*scaleRecip*(lrvir[XX][YY]);
246 lrvir[XX][ZZ]=-0.5*scaleRecip*(lrvir[XX][ZZ]);
247 lrvir[YY][YY]=-0.5*scaleRecip*(lrvir[YY][YY]+energy);
248 lrvir[YY][ZZ]=-0.5*scaleRecip*(lrvir[YY][ZZ]);
249 lrvir[ZZ][ZZ]=-0.5*scaleRecip*(lrvir[ZZ][ZZ]+energy);
251 lrvir[YY][XX]=lrvir[XX][YY];
252 lrvir[ZZ][XX]=lrvir[XX][ZZ];
253 lrvir[ZZ][YY]=lrvir[YY][ZZ];