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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)
84 printf("Go away! kmax = %d\n", kmax);
88 for (i = 0; (i < natom); i++)
90 for (m = 0; (m < 3); m++)
96 for (m = 0; (m < 3); m++)
98 eir[1][i][m].re = cos(x[i][m]*lll[m]);
99 eir[1][i][m].im = sin(x[i][m]*lll[m]);
101 for (j = 2; (j < kmax); j++)
103 for (m = 0; (m < 3); m++)
105 eir[j][i][m] = cmul(eir[j-1][i][m], eir[1][i][m]);
111 void init_ewald_tab(ewald_tab_t *et, const t_inputrec *ir, FILE *fp)
118 fprintf(fp, "Will do ordinary reciprocal space Ewald sum.\n");
121 (*et)->nx = ir->nkx+1;
122 (*et)->ny = ir->nky+1;
123 (*et)->nz = ir->nkz+1;
124 (*et)->kmax = max((*et)->nx, max((*et)->ny, (*et)->nz));
126 (*et)->tab_xy = NULL;
127 (*et)->tab_qxyz = NULL;
132 real do_ewald(FILE *log, gmx_bool bVerbose,
135 real chargeA[], real chargeB[],
137 t_commrec *cr, int natoms,
138 matrix lrvir, real ewaldcoeff,
139 real lambda, real *dvdlambda,
142 real factor = -1.0/(4*ewaldcoeff*ewaldcoeff);
143 real scaleRecip = 4.0*M_PI/(box[XX]*box[YY]*box[ZZ])*ONE_4PI_EPS0/ir->epsilon_r; /* 1/(Vol*e0) */
144 real *charge, energy_AB[2], energy;
146 int lowiy, lowiz, ix, iy, iz, n, q;
147 real tmp, cs, ss, ak, akv, mx, my, mz, m2, scale;
148 gmx_bool bFreeEnergy;
154 gmx_fatal(FARGS, "No parallel Ewald. Use PME instead.\n");
159 if (!et->eir) /* allocate if we need to */
161 snew(et->eir, et->kmax);
162 for (n = 0; n < et->kmax; n++)
164 snew(et->eir[n], natoms);
166 snew(et->tab_xy, natoms);
167 snew(et->tab_qxyz, natoms);
170 bFreeEnergy = (ir->efep != efepNO);
175 /* make tables for the structure factor parts */
176 tabulate_eir(natoms, x, et->kmax, et->eir, lll);
178 for (q = 0; q < (bFreeEnergy ? 2 : 1); q++)
188 scale = 1.0 - lambda;
198 for (ix = 0; ix < et->nx; ix++)
201 for (iy = lowiy; iy < et->ny; iy++)
206 for (n = 0; n < natoms; n++)
208 et->tab_xy[n] = cmul(et->eir[ix][n][XX], et->eir[iy][n][YY]);
213 for (n = 0; n < natoms; n++)
215 et->tab_xy[n] = conjmul(et->eir[ix][n][XX], et->eir[-iy][n][YY]);
218 for (iz = lowiz; iz < et->nz; iz++)
221 m2 = mx*mx+my*my+mz*mz;
222 ak = exp(m2*factor)/m2;
223 akv = 2.0*ak*(1.0/m2-factor);
226 for (n = 0; n < natoms; n++)
228 et->tab_qxyz[n] = rcmul(charge[n], cmul(et->tab_xy[n],
229 et->eir[iz][n][ZZ]));
234 for (n = 0; n < natoms; n++)
236 et->tab_qxyz[n] = rcmul(charge[n], conjmul(et->tab_xy[n],
237 et->eir[-iz][n][ZZ]));
242 for (n = 0; n < natoms; n++)
244 cs += et->tab_qxyz[n].re;
245 ss += et->tab_qxyz[n].im;
247 energy_AB[q] += ak*(cs*cs+ss*ss);
248 tmp = scale*akv*(cs*cs+ss*ss);
249 lrvir[XX][XX] -= tmp*mx*mx;
250 lrvir[XX][YY] -= tmp*mx*my;
251 lrvir[XX][ZZ] -= tmp*mx*mz;
252 lrvir[YY][YY] -= tmp*my*my;
253 lrvir[YY][ZZ] -= tmp*my*mz;
254 lrvir[ZZ][ZZ] -= tmp*mz*mz;
255 for (n = 0; n < natoms; n++)
257 /*tmp=scale*ak*(cs*tab_qxyz[n].im-ss*tab_qxyz[n].re);*/
258 tmp = scale*ak*(cs*et->tab_qxyz[n].im-ss*et->tab_qxyz[n].re);
259 f[n][XX] += tmp*mx*2*scaleRecip;
260 f[n][YY] += tmp*my*2*scaleRecip;
261 f[n][ZZ] += tmp*mz*2*scaleRecip;
277 energy = energy_AB[0];
281 energy = (1.0 - lambda)*energy_AB[0] + lambda*energy_AB[1];
282 *dvdlambda += scaleRecip*(energy_AB[1] - energy_AB[0]);
285 lrvir[XX][XX] = -0.5*scaleRecip*(lrvir[XX][XX]+energy);
286 lrvir[XX][YY] = -0.5*scaleRecip*(lrvir[XX][YY]);
287 lrvir[XX][ZZ] = -0.5*scaleRecip*(lrvir[XX][ZZ]);
288 lrvir[YY][YY] = -0.5*scaleRecip*(lrvir[YY][YY]+energy);
289 lrvir[YY][ZZ] = -0.5*scaleRecip*(lrvir[YY][ZZ]);
290 lrvir[ZZ][ZZ] = -0.5*scaleRecip*(lrvir[ZZ][ZZ]+energy);
292 lrvir[YY][XX] = lrvir[XX][YY];
293 lrvir[ZZ][XX] = lrvir[XX][ZZ];
294 lrvir[ZZ][YY] = lrvir[YY][ZZ];
296 energy *= scaleRecip;