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45 #include "gmxcomplex.h"
47 #include "gromacs/fileio/futil.h"
48 #include "gmx_fatal.h"
59 t_complex *tab_xy, *tab_qxyz;
64 /* TODO: fix thread-safety */
66 /* the other routines are in complex.h */
67 static t_complex conjmul(t_complex a, t_complex b)
71 c.re = a.re*b.re + a.im*b.im;
72 c.im = a.im*b.re - a.re*b.im;
80 static void tabulate_eir(int natom, rvec x[], int kmax, cvec **eir, rvec lll)
86 printf("Go away! kmax = %d\n", kmax);
90 for (i = 0; (i < natom); i++)
92 for (m = 0; (m < 3); m++)
98 for (m = 0; (m < 3); m++)
100 eir[1][i][m].re = cos(x[i][m]*lll[m]);
101 eir[1][i][m].im = sin(x[i][m]*lll[m]);
103 for (j = 2; (j < kmax); j++)
105 for (m = 0; (m < 3); m++)
107 eir[j][i][m] = cmul(eir[j-1][i][m], eir[1][i][m]);
113 void init_ewald_tab(ewald_tab_t *et, const t_inputrec *ir, FILE *fp)
120 fprintf(fp, "Will do ordinary reciprocal space Ewald sum.\n");
123 (*et)->nx = ir->nkx+1;
124 (*et)->ny = ir->nky+1;
125 (*et)->nz = ir->nkz+1;
126 (*et)->kmax = max((*et)->nx, max((*et)->ny, (*et)->nz));
128 (*et)->tab_xy = NULL;
129 (*et)->tab_qxyz = NULL;
134 real do_ewald(t_inputrec *ir,
136 real chargeA[], real chargeB[],
138 t_commrec *cr, int natoms,
139 matrix lrvir, real ewaldcoeff,
140 real lambda, real *dvdlambda,
143 real factor = -1.0/(4*ewaldcoeff*ewaldcoeff);
144 real scaleRecip = 4.0*M_PI/(box[XX]*box[YY]*box[ZZ])*ONE_4PI_EPS0/ir->epsilon_r; /* 1/(Vol*e0) */
145 real *charge, energy_AB[2], energy;
147 int lowiy, lowiz, ix, iy, iz, n, q;
148 real tmp, cs, ss, ak, akv, mx, my, mz, m2, scale;
149 gmx_bool bFreeEnergy;
155 gmx_fatal(FARGS, "No parallel Ewald. Use PME instead.\n");
160 if (!et->eir) /* allocate if we need to */
162 snew(et->eir, et->kmax);
163 for (n = 0; n < et->kmax; n++)
165 snew(et->eir[n], natoms);
167 snew(et->tab_xy, natoms);
168 snew(et->tab_qxyz, natoms);
171 bFreeEnergy = (ir->efep != efepNO);
176 /* make tables for the structure factor parts */
177 tabulate_eir(natoms, x, et->kmax, et->eir, lll);
179 for (q = 0; q < (bFreeEnergy ? 2 : 1); q++)
189 scale = 1.0 - lambda;
199 for (ix = 0; ix < et->nx; ix++)
202 for (iy = lowiy; iy < et->ny; iy++)
207 for (n = 0; n < natoms; n++)
209 et->tab_xy[n] = cmul(et->eir[ix][n][XX], et->eir[iy][n][YY]);
214 for (n = 0; n < natoms; n++)
216 et->tab_xy[n] = conjmul(et->eir[ix][n][XX], et->eir[-iy][n][YY]);
219 for (iz = lowiz; iz < et->nz; iz++)
222 m2 = mx*mx+my*my+mz*mz;
223 ak = exp(m2*factor)/m2;
224 akv = 2.0*ak*(1.0/m2-factor);
227 for (n = 0; n < natoms; n++)
229 et->tab_qxyz[n] = rcmul(charge[n], cmul(et->tab_xy[n],
230 et->eir[iz][n][ZZ]));
235 for (n = 0; n < natoms; n++)
237 et->tab_qxyz[n] = rcmul(charge[n], conjmul(et->tab_xy[n],
238 et->eir[-iz][n][ZZ]));
243 for (n = 0; n < natoms; n++)
245 cs += et->tab_qxyz[n].re;
246 ss += et->tab_qxyz[n].im;
248 energy_AB[q] += ak*(cs*cs+ss*ss);
249 tmp = scale*akv*(cs*cs+ss*ss);
250 lrvir[XX][XX] -= tmp*mx*mx;
251 lrvir[XX][YY] -= tmp*mx*my;
252 lrvir[XX][ZZ] -= tmp*mx*mz;
253 lrvir[YY][YY] -= tmp*my*my;
254 lrvir[YY][ZZ] -= tmp*my*mz;
255 lrvir[ZZ][ZZ] -= tmp*mz*mz;
256 for (n = 0; n < natoms; n++)
258 /*tmp=scale*ak*(cs*tab_qxyz[n].im-ss*tab_qxyz[n].re);*/
259 tmp = scale*ak*(cs*et->tab_qxyz[n].im-ss*et->tab_qxyz[n].re);
260 f[n][XX] += tmp*mx*2*scaleRecip;
261 f[n][YY] += tmp*my*2*scaleRecip;
262 f[n][ZZ] += tmp*mz*2*scaleRecip;
278 energy = energy_AB[0];
282 energy = (1.0 - lambda)*energy_AB[0] + lambda*energy_AB[1];
283 *dvdlambda += scaleRecip*(energy_AB[1] - energy_AB[0]);
286 lrvir[XX][XX] = -0.5*scaleRecip*(lrvir[XX][XX]+energy);
287 lrvir[XX][YY] = -0.5*scaleRecip*(lrvir[XX][YY]);
288 lrvir[XX][ZZ] = -0.5*scaleRecip*(lrvir[XX][ZZ]);
289 lrvir[YY][YY] = -0.5*scaleRecip*(lrvir[YY][YY]+energy);
290 lrvir[YY][ZZ] = -0.5*scaleRecip*(lrvir[YY][ZZ]);
291 lrvir[ZZ][ZZ] = -0.5*scaleRecip*(lrvir[ZZ][ZZ]+energy);
293 lrvir[YY][XX] = lrvir[XX][YY];
294 lrvir[ZZ][XX] = lrvir[XX][ZZ];
295 lrvir[ZZ][YY] = lrvir[YY][ZZ];
297 energy *= scaleRecip;