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root/OpenMD/trunk/src/nonbonded/Electrostatic.cpp
Revision: 1925
Committed: Wed Aug 7 15:24:16 2013 UTC (11 years, 9 months ago) by gezelter
File size: 54231 byte(s)
Log Message:
More ewald fixes, reporting reciprocal potential in stats.

File Contents

# Content
1 /*
2 * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
3 *
4 * The University of Notre Dame grants you ("Licensee") a
5 * non-exclusive, royalty free, license to use, modify and
6 * redistribute this software in source and binary code form, provided
7 * that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the
15 * distribution.
16 *
17 * This software is provided "AS IS," without a warranty of any
18 * kind. All express or implied conditions, representations and
19 * warranties, including any implied warranty of merchantability,
20 * fitness for a particular purpose or non-infringement, are hereby
21 * excluded. The University of Notre Dame and its licensors shall not
22 * be liable for any damages suffered by licensee as a result of
23 * using, modifying or distributing the software or its
24 * derivatives. In no event will the University of Notre Dame or its
25 * licensors be liable for any lost revenue, profit or data, or for
26 * direct, indirect, special, consequential, incidental or punitive
27 * damages, however caused and regardless of the theory of liability,
28 * arising out of the use of or inability to use software, even if the
29 * University of Notre Dame has been advised of the possibility of
30 * such damages.
31 *
32 * SUPPORT OPEN SCIENCE! If you use OpenMD or its source code in your
33 * research, please cite the appropriate papers when you publish your
34 * work. Good starting points are:
35 *
36 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
37 * [2] Fennell & Gezelter, J. Chem. Phys. 124 234104 (2006).
38 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
39 * [4] Kuang & Gezelter, J. Chem. Phys. 133, 164101 (2010).
40 * [5] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
41 */
42
43 #include <stdio.h>
44 #include <string.h>
45
46 #include <cmath>
47 #include <numeric>
48 #include "nonbonded/Electrostatic.hpp"
49 #include "utils/simError.h"
50 #include "types/NonBondedInteractionType.hpp"
51 #include "types/FixedChargeAdapter.hpp"
52 #include "types/FluctuatingChargeAdapter.hpp"
53 #include "types/MultipoleAdapter.hpp"
54 #include "io/Globals.hpp"
55 #include "nonbonded/SlaterIntegrals.hpp"
56 #include "utils/PhysicalConstants.hpp"
57 #include "math/erfc.hpp"
58 #include "math/SquareMatrix.hpp"
59 #include "primitives/Molecule.hpp"
60 #ifdef IS_MPI
61 #include <mpi.h>
62 #endif
63
64 namespace OpenMD {
65
66 Electrostatic::Electrostatic(): name_("Electrostatic"), initialized_(false),
67 forceField_(NULL), info_(NULL),
68 haveCutoffRadius_(false),
69 haveDampingAlpha_(false),
70 haveDielectric_(false),
71 haveElectroSplines_(false)
72 {}
73
74 void Electrostatic::initialize() {
75
76 Globals* simParams_ = info_->getSimParams();
77
78 summationMap_["HARD"] = esm_HARD;
79 summationMap_["NONE"] = esm_HARD;
80 summationMap_["SWITCHING_FUNCTION"] = esm_SWITCHING_FUNCTION;
81 summationMap_["SHIFTED_POTENTIAL"] = esm_SHIFTED_POTENTIAL;
82 summationMap_["SHIFTED_FORCE"] = esm_SHIFTED_FORCE;
83 summationMap_["TAYLOR_SHIFTED"] = esm_TAYLOR_SHIFTED;
84 summationMap_["REACTION_FIELD"] = esm_REACTION_FIELD;
85 summationMap_["EWALD_FULL"] = esm_EWALD_FULL;
86 summationMap_["EWALD_PME"] = esm_EWALD_PME;
87 summationMap_["EWALD_SPME"] = esm_EWALD_SPME;
88 screeningMap_["DAMPED"] = DAMPED;
89 screeningMap_["UNDAMPED"] = UNDAMPED;
90
91 // these prefactors convert the multipole interactions into kcal / mol
92 // all were computed assuming distances are measured in angstroms
93 // Charge-Charge, assuming charges are measured in electrons
94 pre11_ = 332.0637778;
95 // Charge-Dipole, assuming charges are measured in electrons, and
96 // dipoles are measured in debyes
97 pre12_ = 69.13373;
98 // Dipole-Dipole, assuming dipoles are measured in Debye
99 pre22_ = 14.39325;
100 // Charge-Quadrupole, assuming charges are measured in electrons, and
101 // quadrupoles are measured in 10^-26 esu cm^2
102 // This unit is also known affectionately as an esu centibarn.
103 pre14_ = 69.13373;
104 // Dipole-Quadrupole, assuming dipoles are measured in debyes and
105 // quadrupoles in esu centibarns:
106 pre24_ = 14.39325;
107 // Quadrupole-Quadrupole, assuming esu centibarns:
108 pre44_ = 14.39325;
109
110 // conversions for the simulation box dipole moment
111 chargeToC_ = 1.60217733e-19;
112 angstromToM_ = 1.0e-10;
113 debyeToCm_ = 3.33564095198e-30;
114
115 // Default number of points for electrostatic splines
116 np_ = 100;
117
118 // variables to handle different summation methods for long-range
119 // electrostatics:
120 summationMethod_ = esm_HARD;
121 screeningMethod_ = UNDAMPED;
122 dielectric_ = 1.0;
123
124 // check the summation method:
125 if (simParams_->haveElectrostaticSummationMethod()) {
126 string myMethod = simParams_->getElectrostaticSummationMethod();
127 toUpper(myMethod);
128 map<string, ElectrostaticSummationMethod>::iterator i;
129 i = summationMap_.find(myMethod);
130 if ( i != summationMap_.end() ) {
131 summationMethod_ = (*i).second;
132 } else {
133 // throw error
134 sprintf( painCave.errMsg,
135 "Electrostatic::initialize: Unknown electrostaticSummationMethod.\n"
136 "\t(Input file specified %s .)\n"
137 "\telectrostaticSummationMethod must be one of: \"hard\",\n"
138 "\t\"shifted_potential\", \"shifted_force\",\n"
139 "\t\"taylor_shifted\", or \"reaction_field\".\n",
140 myMethod.c_str() );
141 painCave.isFatal = 1;
142 simError();
143 }
144 } else {
145 // set ElectrostaticSummationMethod to the cutoffMethod:
146 if (simParams_->haveCutoffMethod()){
147 string myMethod = simParams_->getCutoffMethod();
148 toUpper(myMethod);
149 map<string, ElectrostaticSummationMethod>::iterator i;
150 i = summationMap_.find(myMethod);
151 if ( i != summationMap_.end() ) {
152 summationMethod_ = (*i).second;
153 }
154 }
155 }
156
157 if (summationMethod_ == esm_REACTION_FIELD) {
158 if (!simParams_->haveDielectric()) {
159 // throw warning
160 sprintf( painCave.errMsg,
161 "SimInfo warning: dielectric was not specified in the input file\n\tfor the reaction field correction method.\n"
162 "\tA default value of %f will be used for the dielectric.\n", dielectric_);
163 painCave.isFatal = 0;
164 painCave.severity = OPENMD_INFO;
165 simError();
166 } else {
167 dielectric_ = simParams_->getDielectric();
168 }
169 haveDielectric_ = true;
170 }
171
172 if (simParams_->haveElectrostaticScreeningMethod()) {
173 string myScreen = simParams_->getElectrostaticScreeningMethod();
174 toUpper(myScreen);
175 map<string, ElectrostaticScreeningMethod>::iterator i;
176 i = screeningMap_.find(myScreen);
177 if ( i != screeningMap_.end()) {
178 screeningMethod_ = (*i).second;
179 } else {
180 sprintf( painCave.errMsg,
181 "SimInfo error: Unknown electrostaticScreeningMethod.\n"
182 "\t(Input file specified %s .)\n"
183 "\telectrostaticScreeningMethod must be one of: \"undamped\"\n"
184 "or \"damped\".\n", myScreen.c_str() );
185 painCave.isFatal = 1;
186 simError();
187 }
188 }
189
190 // check to make sure a cutoff value has been set:
191 if (!haveCutoffRadius_) {
192 sprintf( painCave.errMsg, "Electrostatic::initialize has no Default "
193 "Cutoff value!\n");
194 painCave.severity = OPENMD_ERROR;
195 painCave.isFatal = 1;
196 simError();
197 }
198
199 if (screeningMethod_ == DAMPED || summationMethod_ == esm_EWALD_FULL) {
200 if (!simParams_->haveDampingAlpha()) {
201 // first set a cutoff dependent alpha value
202 // we assume alpha depends linearly with rcut from 0 to 20.5 ang
203 dampingAlpha_ = 0.425 - cutoffRadius_* 0.02;
204 if (dampingAlpha_ < 0.0) dampingAlpha_ = 0.0;
205 // throw warning
206 sprintf( painCave.errMsg,
207 "Electrostatic::initialize: dampingAlpha was not specified in the\n"
208 "\tinput file. A default value of %f (1/ang) will be used for the\n"
209 "\tcutoff of %f (ang).\n",
210 dampingAlpha_, cutoffRadius_);
211 painCave.severity = OPENMD_INFO;
212 painCave.isFatal = 0;
213 simError();
214 } else {
215 dampingAlpha_ = simParams_->getDampingAlpha();
216 }
217 haveDampingAlpha_ = true;
218 }
219
220
221 Etypes.clear();
222 Etids.clear();
223 FQtypes.clear();
224 FQtids.clear();
225 ElectrostaticMap.clear();
226 Jij.clear();
227 nElectro_ = 0;
228 nFlucq_ = 0;
229
230 Etids.resize( forceField_->getNAtomType(), -1);
231 FQtids.resize( forceField_->getNAtomType(), -1);
232
233 set<AtomType*>::iterator at;
234 for (at = simTypes_.begin(); at != simTypes_.end(); ++at) {
235 if ((*at)->isElectrostatic()) nElectro_++;
236 if ((*at)->isFluctuatingCharge()) nFlucq_++;
237 }
238
239 Jij.resize(nFlucq_);
240
241 for (at = simTypes_.begin(); at != simTypes_.end(); ++at) {
242 if ((*at)->isElectrostatic()) addType(*at);
243 }
244
245 if (summationMethod_ == esm_REACTION_FIELD) {
246 preRF_ = (dielectric_ - 1.0) /
247 ((2.0 * dielectric_ + 1.0) * pow(cutoffRadius_,3) );
248 }
249
250 RealType b0c, b1c, b2c, b3c, b4c, b5c;
251 RealType db0c_1, db0c_2, db0c_3, db0c_4, db0c_5;
252 RealType a2, expTerm, invArootPi;
253
254 RealType r = cutoffRadius_;
255 RealType r2 = r * r;
256 RealType ric = 1.0 / r;
257 RealType ric2 = ric * ric;
258
259 if (screeningMethod_ == DAMPED) {
260 a2 = dampingAlpha_ * dampingAlpha_;
261 invArootPi = 1.0 / (dampingAlpha_ * sqrt(M_PI));
262 expTerm = exp(-a2 * r2);
263 // values of Smith's B_l functions at the cutoff radius:
264 b0c = erfc(dampingAlpha_ * r) / r;
265 b1c = ( b0c + 2.0*a2 * expTerm * invArootPi) / r2;
266 b2c = (3.0 * b1c + pow(2.0*a2, 2) * expTerm * invArootPi) / r2;
267 b3c = (5.0 * b2c + pow(2.0*a2, 3) * expTerm * invArootPi) / r2;
268 b4c = (7.0 * b3c + pow(2.0*a2, 4) * expTerm * invArootPi) / r2;
269 b5c = (9.0 * b4c + pow(2.0*a2, 5) * expTerm * invArootPi) / r2;
270 // Half the Smith self piece:
271 selfMult1_ = - a2 * invArootPi;
272 selfMult2_ = - 2.0 * a2 * a2 * invArootPi / 3.0;
273 selfMult4_ = - 4.0 * a2 * a2 * a2 * invArootPi / 5.0;
274 } else {
275 a2 = 0.0;
276 b0c = 1.0 / r;
277 b1c = ( b0c) / r2;
278 b2c = (3.0 * b1c) / r2;
279 b3c = (5.0 * b2c) / r2;
280 b4c = (7.0 * b3c) / r2;
281 b5c = (9.0 * b4c) / r2;
282 selfMult1_ = 0.0;
283 selfMult2_ = 0.0;
284 selfMult4_ = 0.0;
285 }
286
287 // higher derivatives of B_0 at the cutoff radius:
288 db0c_1 = -r * b1c;
289 db0c_2 = -b1c + r2 * b2c;
290 db0c_3 = 3.0*r*b2c - r2*r*b3c;
291 db0c_4 = 3.0*b2c - 6.0*r2*b3c + r2*r2*b4c;
292 db0c_5 = -15.0*r*b3c + 10.0*r2*r*b4c - r2*r2*r*b5c;
293
294 if (summationMethod_ != esm_EWALD_FULL) {
295 selfMult1_ -= b0c;
296 selfMult2_ += (db0c_2 + 2.0*db0c_1*ric) / 3.0;
297 selfMult4_ -= (db0c_4 + 4.0*db0c_3*ric) / 15.0;
298 }
299
300 // working variables for the splines:
301 RealType ri, ri2;
302 RealType b0, b1, b2, b3, b4, b5;
303 RealType db0_1, db0_2, db0_3, db0_4, db0_5;
304 RealType f, fc, f0;
305 RealType g, gc, g0, g1, g2, g3, g4;
306 RealType h, hc, h1, h2, h3, h4;
307 RealType s, sc, s2, s3, s4;
308 RealType t, tc, t3, t4;
309 RealType u, uc, u4;
310
311 // working variables for Taylor expansion:
312 RealType rmRc, rmRc2, rmRc3, rmRc4;
313
314 // Approximate using splines using a maximum of 0.1 Angstroms
315 // between points.
316 int nptest = int((cutoffRadius_ + 2.0) / 0.1);
317 np_ = (np_ > nptest) ? np_ : nptest;
318
319 // Add a 2 angstrom safety window to deal with cutoffGroups that
320 // have charged atoms longer than the cutoffRadius away from each
321 // other. Splining is almost certainly the best choice here.
322 // Direct calls to erfc would be preferrable if it is a very fast
323 // implementation.
324
325 RealType dx = (cutoffRadius_ + 2.0) / RealType(np_);
326
327 // Storage vectors for the computed functions
328 vector<RealType> rv;
329 vector<RealType> v01v;
330 vector<RealType> v11v;
331 vector<RealType> v21v, v22v;
332 vector<RealType> v31v, v32v;
333 vector<RealType> v41v, v42v, v43v;
334
335 for (int i = 1; i < np_ + 1; i++) {
336 r = RealType(i) * dx;
337 rv.push_back(r);
338
339 ri = 1.0 / r;
340 ri2 = ri * ri;
341
342 r2 = r * r;
343 expTerm = exp(-a2 * r2);
344
345 // Taylor expansion factors (no need for factorials this way):
346 rmRc = r - cutoffRadius_;
347 rmRc2 = rmRc * rmRc / 2.0;
348 rmRc3 = rmRc2 * rmRc / 3.0;
349 rmRc4 = rmRc3 * rmRc / 4.0;
350
351 // values of Smith's B_l functions at r:
352 if (screeningMethod_ == DAMPED) {
353 b0 = erfc(dampingAlpha_ * r) * ri;
354 b1 = ( b0 + 2.0*a2 * expTerm * invArootPi) * ri2;
355 b2 = (3.0 * b1 + pow(2.0*a2, 2) * expTerm * invArootPi) * ri2;
356 b3 = (5.0 * b2 + pow(2.0*a2, 3) * expTerm * invArootPi) * ri2;
357 b4 = (7.0 * b3 + pow(2.0*a2, 4) * expTerm * invArootPi) * ri2;
358 b5 = (9.0 * b4 + pow(2.0*a2, 5) * expTerm * invArootPi) * ri2;
359 } else {
360 b0 = ri;
361 b1 = ( b0) * ri2;
362 b2 = (3.0 * b1) * ri2;
363 b3 = (5.0 * b2) * ri2;
364 b4 = (7.0 * b3) * ri2;
365 b5 = (9.0 * b4) * ri2;
366 }
367
368 // higher derivatives of B_0 at r:
369 db0_1 = -r * b1;
370 db0_2 = -b1 + r2 * b2;
371 db0_3 = 3.0*r*b2 - r2*r*b3;
372 db0_4 = 3.0*b2 - 6.0*r2*b3 + r2*r2*b4;
373 db0_5 = -15.0*r*b3 + 10.0*r2*r*b4 - r2*r2*r*b5;
374
375 f = b0;
376 fc = b0c;
377 f0 = f - fc - rmRc*db0c_1;
378
379 g = db0_1;
380 gc = db0c_1;
381 g0 = g - gc;
382 g1 = g0 - rmRc *db0c_2;
383 g2 = g1 - rmRc2*db0c_3;
384 g3 = g2 - rmRc3*db0c_4;
385 g4 = g3 - rmRc4*db0c_5;
386
387 h = db0_2;
388 hc = db0c_2;
389 h1 = h - hc;
390 h2 = h1 - rmRc *db0c_3;
391 h3 = h2 - rmRc2*db0c_4;
392 h4 = h3 - rmRc3*db0c_5;
393
394 s = db0_3;
395 sc = db0c_3;
396 s2 = s - sc;
397 s3 = s2 - rmRc *db0c_4;
398 s4 = s3 - rmRc2*db0c_5;
399
400 t = db0_4;
401 tc = db0c_4;
402 t3 = t - tc;
403 t4 = t3 - rmRc *db0c_5;
404
405 u = db0_5;
406 uc = db0c_5;
407 u4 = u - uc;
408
409 // in what follows below, the various v functions are used for
410 // potentials and torques, while the w functions show up in the
411 // forces.
412
413 switch (summationMethod_) {
414 case esm_SHIFTED_FORCE:
415
416 v01 = f - fc - rmRc*gc;
417 v11 = g - gc - rmRc*hc;
418 v21 = g*ri - gc*ric - rmRc*(hc - gc*ric)*ric;
419 v22 = h - g*ri - (hc - gc*ric) - rmRc*(sc - (hc - gc*ric)*ric);
420 v31 = (h-g*ri)*ri - (hc-gc*ric)*ric - rmRc*(sc-2.0*(hc-gc*ric)*ric)*ric;
421 v32 = (s - 3.0*(h-g*ri)*ri) - (sc - 3.0*(hc-gc*ric)*ric)
422 - rmRc*(tc - 3.0*(sc-2.0*(hc-gc*ric)*ric)*ric);
423 v41 = (h - g*ri)*ri2 - (hc - gc*ric)*ric2
424 - rmRc*(sc - 3.0*(hc-gc*ric)*ric)*ric2;
425 v42 = (s-3.0*(h-g*ri)*ri)*ri - (sc-3.0*(hc-gc*ric)*ric)*ric
426 - rmRc*(tc - (4.0*sc - 9.0*(hc - gc*ric)*ric)*ric)*ric;
427
428 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri)
429 - (tc - 3.0*(2.0*sc - 5.0*(hc - gc*ric)*ric)*ric)
430 - rmRc*(uc-3.0*(2.0*tc - (7.0*sc - 15.0*(hc - gc*ric)*ric)*ric)*ric);
431
432 dv01 = g - gc;
433 dv11 = h - hc;
434 dv21 = (h - g*ri)*ri - (hc - gc*ric)*ric;
435 dv22 = (s - (h - g*ri)*ri) - (sc - (hc - gc*ric)*ric);
436 dv31 = (s - 2.0*(h-g*ri)*ri)*ri - (sc - 2.0*(hc-gc*ric)*ric)*ric;
437 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri)
438 - (tc - 3.0*(sc-2.0*(hc-gc*ric)*ric)*ric);
439 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2 - (sc - 3.0*(hc - gc*ric)*ric)*ric2;
440 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri
441 - (tc - (4.0*sc - 9.0*(hc-gc*ric)*ric)*ric)*ric;
442 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri)
443 - (uc - 3.0*(2.0*tc - (7.0*sc - 15.0*(hc - gc*ric)*ric)*ric)*ric);
444
445 break;
446
447 case esm_TAYLOR_SHIFTED:
448
449 v01 = f0;
450 v11 = g1;
451 v21 = g2 * ri;
452 v22 = h2 - v21;
453 v31 = (h3 - g3 * ri) * ri;
454 v32 = s3 - 3.0*v31;
455 v41 = (h4 - g4 * ri) * ri2;
456 v42 = s4 * ri - 3.0*v41;
457 v43 = t4 - 6.0*v42 - 3.0*v41;
458
459 dv01 = g0;
460 dv11 = h1;
461 dv21 = (h2 - g2*ri)*ri;
462 dv22 = (s2 - (h2 - g2*ri)*ri);
463 dv31 = (s3 - 2.0*(h3-g3*ri)*ri)*ri;
464 dv32 = (t3 - 3.0*(s3-2.0*(h3-g3*ri)*ri)*ri);
465 dv41 = (s4 - 3.0*(h4 - g4*ri)*ri)*ri2;
466 dv42 = (t4 - (4.0*s4 - 9.0*(h4-g4*ri)*ri)*ri)*ri;
467 dv43 = (u4 - 3.0*(2.0*t4 - (7.0*s4 - 15.0*(h4 - g4*ri)*ri)*ri)*ri);
468
469 break;
470
471 case esm_SHIFTED_POTENTIAL:
472
473 v01 = f - fc;
474 v11 = g - gc;
475 v21 = g*ri - gc*ric;
476 v22 = h - g*ri - (hc - gc*ric);
477 v31 = (h-g*ri)*ri - (hc-gc*ric)*ric;
478 v32 = (s - 3.0*(h-g*ri)*ri) - (sc - 3.0*(hc-gc*ric)*ric);
479 v41 = (h - g*ri)*ri2 - (hc - gc*ric)*ric2;
480 v42 = (s-3.0*(h-g*ri)*ri)*ri - (sc-3.0*(hc-gc*ric)*ric)*ric;
481 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri)
482 - (tc - 3.0*(2.0*sc - 5.0*(hc - gc*ric)*ric)*ric);
483
484 dv01 = g;
485 dv11 = h;
486 dv21 = (h - g*ri)*ri;
487 dv22 = (s - (h - g*ri)*ri);
488 dv31 = (s - 2.0*(h-g*ri)*ri)*ri;
489 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri);
490 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2;
491 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri;
492 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri);
493
494 break;
495
496 case esm_SWITCHING_FUNCTION:
497 case esm_HARD:
498 case esm_EWALD_FULL:
499
500 v01 = f;
501 v11 = g;
502 v21 = g*ri;
503 v22 = h - g*ri;
504 v31 = (h-g*ri)*ri;
505 v32 = (s - 3.0*(h-g*ri)*ri);
506 v41 = (h - g*ri)*ri2;
507 v42 = (s-3.0*(h-g*ri)*ri)*ri;
508 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri);
509
510 dv01 = g;
511 dv11 = h;
512 dv21 = (h - g*ri)*ri;
513 dv22 = (s - (h - g*ri)*ri);
514 dv31 = (s - 2.0*(h-g*ri)*ri)*ri;
515 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri);
516 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2;
517 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri;
518 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri);
519
520 break;
521
522 case esm_REACTION_FIELD:
523
524 // following DL_POLY's lead for shifting the image charge potential:
525 f = b0 + preRF_ * r2;
526 fc = b0c + preRF_ * cutoffRadius_ * cutoffRadius_;
527
528 g = db0_1 + preRF_ * 2.0 * r;
529 gc = db0c_1 + preRF_ * 2.0 * cutoffRadius_;
530
531 h = db0_2 + preRF_ * 2.0;
532 hc = db0c_2 + preRF_ * 2.0;
533
534 v01 = f - fc;
535 v11 = g - gc;
536 v21 = g*ri - gc*ric;
537 v22 = h - g*ri - (hc - gc*ric);
538 v31 = (h-g*ri)*ri - (hc-gc*ric)*ric;
539 v32 = (s - 3.0*(h-g*ri)*ri) - (sc - 3.0*(hc-gc*ric)*ric);
540 v41 = (h - g*ri)*ri2 - (hc - gc*ric)*ric2;
541 v42 = (s-3.0*(h-g*ri)*ri)*ri - (sc-3.0*(hc-gc*ric)*ric)*ric;
542 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri)
543 - (tc - 3.0*(2.0*sc - 5.0*(hc - gc*ric)*ric)*ric);
544
545 dv01 = g;
546 dv11 = h;
547 dv21 = (h - g*ri)*ri;
548 dv22 = (s - (h - g*ri)*ri);
549 dv31 = (s - 2.0*(h-g*ri)*ri)*ri;
550 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri);
551 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2;
552 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri;
553 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri);
554
555 break;
556
557 case esm_EWALD_PME:
558 case esm_EWALD_SPME:
559 default :
560 map<string, ElectrostaticSummationMethod>::iterator i;
561 std::string meth;
562 for (i = summationMap_.begin(); i != summationMap_.end(); ++i) {
563 if ((*i).second == summationMethod_) meth = (*i).first;
564 }
565 sprintf( painCave.errMsg,
566 "Electrostatic::initialize: electrostaticSummationMethod %s \n"
567 "\thas not been implemented yet. Please select one of:\n"
568 "\t\"hard\", \"shifted_potential\", or \"shifted_force\"\n",
569 meth.c_str() );
570 painCave.isFatal = 1;
571 simError();
572 break;
573 }
574
575 // Add these computed values to the storage vectors for spline creation:
576 v01v.push_back(v01);
577 v11v.push_back(v11);
578 v21v.push_back(v21);
579 v22v.push_back(v22);
580 v31v.push_back(v31);
581 v32v.push_back(v32);
582 v41v.push_back(v41);
583 v42v.push_back(v42);
584 v43v.push_back(v43);
585 }
586
587 // construct the spline structures and fill them with the values we've
588 // computed:
589
590 v01s = new CubicSpline();
591 v01s->addPoints(rv, v01v);
592 v11s = new CubicSpline();
593 v11s->addPoints(rv, v11v);
594 v21s = new CubicSpline();
595 v21s->addPoints(rv, v21v);
596 v22s = new CubicSpline();
597 v22s->addPoints(rv, v22v);
598 v31s = new CubicSpline();
599 v31s->addPoints(rv, v31v);
600 v32s = new CubicSpline();
601 v32s->addPoints(rv, v32v);
602 v41s = new CubicSpline();
603 v41s->addPoints(rv, v41v);
604 v42s = new CubicSpline();
605 v42s->addPoints(rv, v42v);
606 v43s = new CubicSpline();
607 v43s->addPoints(rv, v43v);
608
609 haveElectroSplines_ = true;
610
611 initialized_ = true;
612 }
613
614 void Electrostatic::addType(AtomType* atomType){
615
616 ElectrostaticAtomData electrostaticAtomData;
617 electrostaticAtomData.is_Charge = false;
618 electrostaticAtomData.is_Dipole = false;
619 electrostaticAtomData.is_Quadrupole = false;
620 electrostaticAtomData.is_Fluctuating = false;
621
622 FixedChargeAdapter fca = FixedChargeAdapter(atomType);
623
624 if (fca.isFixedCharge()) {
625 electrostaticAtomData.is_Charge = true;
626 electrostaticAtomData.fixedCharge = fca.getCharge();
627 }
628
629 MultipoleAdapter ma = MultipoleAdapter(atomType);
630 if (ma.isMultipole()) {
631 if (ma.isDipole()) {
632 electrostaticAtomData.is_Dipole = true;
633 electrostaticAtomData.dipole = ma.getDipole();
634 }
635 if (ma.isQuadrupole()) {
636 electrostaticAtomData.is_Quadrupole = true;
637 electrostaticAtomData.quadrupole = ma.getQuadrupole();
638 }
639 }
640
641 FluctuatingChargeAdapter fqa = FluctuatingChargeAdapter(atomType);
642
643 if (fqa.isFluctuatingCharge()) {
644 electrostaticAtomData.is_Fluctuating = true;
645 electrostaticAtomData.electronegativity = fqa.getElectronegativity();
646 electrostaticAtomData.hardness = fqa.getHardness();
647 electrostaticAtomData.slaterN = fqa.getSlaterN();
648 electrostaticAtomData.slaterZeta = fqa.getSlaterZeta();
649 }
650
651 int atid = atomType->getIdent();
652 int etid = Etypes.size();
653 int fqtid = FQtypes.size();
654
655 pair<set<int>::iterator,bool> ret;
656 ret = Etypes.insert( atid );
657 if (ret.second == false) {
658 sprintf( painCave.errMsg,
659 "Electrostatic already had a previous entry with ident %d\n",
660 atid);
661 painCave.severity = OPENMD_INFO;
662 painCave.isFatal = 0;
663 simError();
664 }
665
666 Etids[ atid ] = etid;
667 ElectrostaticMap.push_back(electrostaticAtomData);
668
669 if (electrostaticAtomData.is_Fluctuating) {
670 ret = FQtypes.insert( atid );
671 if (ret.second == false) {
672 sprintf( painCave.errMsg,
673 "Electrostatic already had a previous fluctuating charge entry with ident %d\n",
674 atid );
675 painCave.severity = OPENMD_INFO;
676 painCave.isFatal = 0;
677 simError();
678 }
679 FQtids[atid] = fqtid;
680 Jij[fqtid].resize(nFlucq_);
681
682 // Now, iterate over all known fluctuating and add to the
683 // coulomb integral map:
684
685 std::set<int>::iterator it;
686 for( it = FQtypes.begin(); it != FQtypes.end(); ++it) {
687 int etid2 = Etids[ (*it) ];
688 int fqtid2 = FQtids[ (*it) ];
689 ElectrostaticAtomData eaData2 = ElectrostaticMap[ etid2 ];
690 RealType a = electrostaticAtomData.slaterZeta;
691 RealType b = eaData2.slaterZeta;
692 int m = electrostaticAtomData.slaterN;
693 int n = eaData2.slaterN;
694
695 // Create the spline of the coulombic integral for s-type
696 // Slater orbitals. Add a 2 angstrom safety window to deal
697 // with cutoffGroups that have charged atoms longer than the
698 // cutoffRadius away from each other.
699
700 RealType rval;
701 RealType dr = (cutoffRadius_ + 2.0) / RealType(np_ - 1);
702 vector<RealType> rvals;
703 vector<RealType> Jvals;
704 // don't start at i = 0, as rval = 0 is undefined for the
705 // slater overlap integrals.
706 for (int i = 1; i < np_+1; i++) {
707 rval = RealType(i) * dr;
708 rvals.push_back(rval);
709 Jvals.push_back(sSTOCoulInt( a, b, m, n, rval *
710 PhysicalConstants::angstromToBohr ) *
711 PhysicalConstants::hartreeToKcal );
712 }
713
714 CubicSpline* J = new CubicSpline();
715 J->addPoints(rvals, Jvals);
716 Jij[fqtid][fqtid2] = J;
717 Jij[fqtid2].resize( nFlucq_ );
718 Jij[fqtid2][fqtid] = J;
719 }
720 }
721 return;
722 }
723
724 void Electrostatic::setCutoffRadius( RealType rCut ) {
725 cutoffRadius_ = rCut;
726 haveCutoffRadius_ = true;
727 }
728
729 void Electrostatic::setElectrostaticSummationMethod( ElectrostaticSummationMethod esm ) {
730 summationMethod_ = esm;
731 }
732 void Electrostatic::setElectrostaticScreeningMethod( ElectrostaticScreeningMethod sm ) {
733 screeningMethod_ = sm;
734 }
735 void Electrostatic::setDampingAlpha( RealType alpha ) {
736 dampingAlpha_ = alpha;
737 haveDampingAlpha_ = true;
738 }
739 void Electrostatic::setReactionFieldDielectric( RealType dielectric ){
740 dielectric_ = dielectric;
741 haveDielectric_ = true;
742 }
743
744 void Electrostatic::calcForce(InteractionData &idat) {
745
746 if (!initialized_) initialize();
747
748 data1 = ElectrostaticMap[Etids[idat.atid1]];
749 data2 = ElectrostaticMap[Etids[idat.atid2]];
750
751 U = 0.0; // Potential
752 F.zero(); // Force
753 Ta.zero(); // Torque on site a
754 Tb.zero(); // Torque on site b
755 Ea.zero(); // Electric field at site a
756 Eb.zero(); // Electric field at site b
757 dUdCa = 0.0; // fluctuating charge force at site a
758 dUdCb = 0.0; // fluctuating charge force at site a
759
760 // Indirect interactions mediated by the reaction field.
761 indirect_Pot = 0.0; // Potential
762 indirect_F.zero(); // Force
763 indirect_Ta.zero(); // Torque on site a
764 indirect_Tb.zero(); // Torque on site b
765
766 // Excluded potential that is still computed for fluctuating charges
767 excluded_Pot= 0.0;
768
769
770 // some variables we'll need independent of electrostatic type:
771
772 ri = 1.0 / *(idat.rij);
773 rhat = *(idat.d) * ri;
774
775 // logicals
776
777 a_is_Charge = data1.is_Charge;
778 a_is_Dipole = data1.is_Dipole;
779 a_is_Quadrupole = data1.is_Quadrupole;
780 a_is_Fluctuating = data1.is_Fluctuating;
781
782 b_is_Charge = data2.is_Charge;
783 b_is_Dipole = data2.is_Dipole;
784 b_is_Quadrupole = data2.is_Quadrupole;
785 b_is_Fluctuating = data2.is_Fluctuating;
786
787 // Obtain all of the required radial function values from the
788 // spline structures:
789
790 // needed for fields (and forces):
791 if (a_is_Charge || b_is_Charge) {
792 v01s->getValueAndDerivativeAt( *(idat.rij), v01, dv01);
793 }
794 if (a_is_Dipole || b_is_Dipole) {
795 v11s->getValueAndDerivativeAt( *(idat.rij), v11, dv11);
796 v11or = ri * v11;
797 }
798 if (a_is_Quadrupole || b_is_Quadrupole || (a_is_Dipole && b_is_Dipole)) {
799 v21s->getValueAndDerivativeAt( *(idat.rij), v21, dv21);
800 v22s->getValueAndDerivativeAt( *(idat.rij), v22, dv22);
801 v22or = ri * v22;
802 }
803
804 // needed for potentials (and forces and torques):
805 if ((a_is_Dipole && b_is_Quadrupole) ||
806 (b_is_Dipole && a_is_Quadrupole)) {
807 v31s->getValueAndDerivativeAt( *(idat.rij), v31, dv31);
808 v32s->getValueAndDerivativeAt( *(idat.rij), v32, dv32);
809 v31or = v31 * ri;
810 v32or = v32 * ri;
811 }
812 if (a_is_Quadrupole && b_is_Quadrupole) {
813 v41s->getValueAndDerivativeAt( *(idat.rij), v41, dv41);
814 v42s->getValueAndDerivativeAt( *(idat.rij), v42, dv42);
815 v43s->getValueAndDerivativeAt( *(idat.rij), v43, dv43);
816 v42or = v42 * ri;
817 v43or = v43 * ri;
818 }
819
820 // calculate the single-site contributions (fields, etc).
821
822 if (a_is_Charge) {
823 C_a = data1.fixedCharge;
824
825 if (a_is_Fluctuating) {
826 C_a += *(idat.flucQ1);
827 }
828
829 if (idat.excluded) {
830 *(idat.skippedCharge2) += C_a;
831 } else {
832 // only do the field if we're not excluded:
833 Eb -= C_a * pre11_ * dv01 * rhat;
834 }
835 }
836
837 if (a_is_Dipole) {
838 D_a = *(idat.dipole1);
839 rdDa = dot(rhat, D_a);
840 rxDa = cross(rhat, D_a);
841 if (!idat.excluded)
842 Eb -= pre12_ * ((dv11-v11or) * rdDa * rhat + v11or * D_a);
843 }
844
845 if (a_is_Quadrupole) {
846 Q_a = *(idat.quadrupole1);
847 trQa = Q_a.trace();
848 Qar = Q_a * rhat;
849 rQa = rhat * Q_a;
850 rdQar = dot(rhat, Qar);
851 rxQar = cross(rhat, Qar);
852 if (!idat.excluded)
853 Eb -= pre14_ * (trQa * rhat * dv21 + 2.0 * Qar * v22or
854 + rdQar * rhat * (dv22 - 2.0*v22or));
855 }
856
857 if (b_is_Charge) {
858 C_b = data2.fixedCharge;
859
860 if (b_is_Fluctuating)
861 C_b += *(idat.flucQ2);
862
863 if (idat.excluded) {
864 *(idat.skippedCharge1) += C_b;
865 } else {
866 // only do the field if we're not excluded:
867 Ea += C_b * pre11_ * dv01 * rhat;
868 }
869 }
870
871 if (b_is_Dipole) {
872 D_b = *(idat.dipole2);
873 rdDb = dot(rhat, D_b);
874 rxDb = cross(rhat, D_b);
875 if (!idat.excluded)
876 Ea += pre12_ * ((dv11-v11or) * rdDb * rhat + v11or * D_b);
877 }
878
879 if (b_is_Quadrupole) {
880 Q_b = *(idat.quadrupole2);
881 trQb = Q_b.trace();
882 Qbr = Q_b * rhat;
883 rQb = rhat * Q_b;
884 rdQbr = dot(rhat, Qbr);
885 rxQbr = cross(rhat, Qbr);
886 if (!idat.excluded)
887 Ea += pre14_ * (trQb * rhat * dv21 + 2.0 * Qbr * v22or
888 + rdQbr * rhat * (dv22 - 2.0*v22or));
889 }
890
891 if ((a_is_Fluctuating || b_is_Fluctuating) && idat.excluded) {
892 J = Jij[FQtids[idat.atid1]][FQtids[idat.atid2]];
893 }
894
895 if (a_is_Charge) {
896
897 if (b_is_Charge) {
898 pref = pre11_ * *(idat.electroMult);
899 U += C_a * C_b * pref * v01;
900 F += C_a * C_b * pref * dv01 * rhat;
901
902 // If this is an excluded pair, there are still indirect
903 // interactions via the reaction field we must worry about:
904
905 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
906 rfContrib = preRF_ * pref * C_a * C_b * *(idat.r2);
907 indirect_Pot += rfContrib;
908 indirect_F += rfContrib * 2.0 * ri * rhat;
909 }
910
911 // Fluctuating charge forces are handled via Coulomb integrals
912 // for excluded pairs (i.e. those connected via bonds) and
913 // with the standard charge-charge interaction otherwise.
914
915 if (idat.excluded) {
916 if (a_is_Fluctuating || b_is_Fluctuating) {
917 coulInt = J->getValueAt( *(idat.rij) );
918 if (a_is_Fluctuating) dUdCa += coulInt * C_b;
919 if (b_is_Fluctuating) dUdCb += coulInt * C_a;
920 excluded_Pot += C_a * C_b * coulInt;
921 }
922 } else {
923 if (a_is_Fluctuating) dUdCa += C_b * pref * v01;
924 if (a_is_Fluctuating) dUdCb += C_a * pref * v01;
925 }
926 }
927
928 if (b_is_Dipole) {
929 pref = pre12_ * *(idat.electroMult);
930 U += C_a * pref * v11 * rdDb;
931 F += C_a * pref * ((dv11 - v11or) * rdDb * rhat + v11or * D_b);
932 Tb += C_a * pref * v11 * rxDb;
933
934 if (a_is_Fluctuating) dUdCa += pref * v11 * rdDb;
935
936 // Even if we excluded this pair from direct interactions, we
937 // still have the reaction-field-mediated charge-dipole
938 // interaction:
939
940 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
941 rfContrib = C_a * pref * preRF_ * 2.0 * *(idat.rij);
942 indirect_Pot += rfContrib * rdDb;
943 indirect_F += rfContrib * D_b / (*idat.rij);
944 indirect_Tb += C_a * pref * preRF_ * rxDb;
945 }
946 }
947
948 if (b_is_Quadrupole) {
949 pref = pre14_ * *(idat.electroMult);
950 U += C_a * pref * (v21 * trQb + v22 * rdQbr);
951 F += C_a * pref * (trQb * dv21 * rhat + 2.0 * Qbr * v22or);
952 F += C_a * pref * rdQbr * rhat * (dv22 - 2.0*v22or);
953 Tb += C_a * pref * 2.0 * rxQbr * v22;
954
955 if (a_is_Fluctuating) dUdCa += pref * (v21 * trQb + v22 * rdQbr);
956 }
957 }
958
959 if (a_is_Dipole) {
960
961 if (b_is_Charge) {
962 pref = pre12_ * *(idat.electroMult);
963
964 U -= C_b * pref * v11 * rdDa;
965 F -= C_b * pref * ((dv11-v11or) * rdDa * rhat + v11or * D_a);
966 Ta -= C_b * pref * v11 * rxDa;
967
968 if (b_is_Fluctuating) dUdCb -= pref * v11 * rdDa;
969
970 // Even if we excluded this pair from direct interactions,
971 // we still have the reaction-field-mediated charge-dipole
972 // interaction:
973 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
974 rfContrib = C_b * pref * preRF_ * 2.0 * *(idat.rij);
975 indirect_Pot -= rfContrib * rdDa;
976 indirect_F -= rfContrib * D_a / (*idat.rij);
977 indirect_Ta -= C_b * pref * preRF_ * rxDa;
978 }
979 }
980
981 if (b_is_Dipole) {
982 pref = pre22_ * *(idat.electroMult);
983 DadDb = dot(D_a, D_b);
984 DaxDb = cross(D_a, D_b);
985
986 U -= pref * (DadDb * v21 + rdDa * rdDb * v22);
987 F -= pref * (dv21 * DadDb * rhat + v22or * (rdDb * D_a + rdDa * D_b));
988 F -= pref * (rdDa * rdDb) * (dv22 - 2.0*v22or) * rhat;
989 Ta += pref * ( v21 * DaxDb - v22 * rdDb * rxDa);
990 Tb += pref * (-v21 * DaxDb - v22 * rdDa * rxDb);
991
992 // Even if we excluded this pair from direct interactions, we
993 // still have the reaction-field-mediated dipole-dipole
994 // interaction:
995 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
996 rfContrib = -pref * preRF_ * 2.0;
997 indirect_Pot += rfContrib * DadDb;
998 indirect_Ta += rfContrib * DaxDb;
999 indirect_Tb -= rfContrib * DaxDb;
1000 }
1001 }
1002
1003 if (b_is_Quadrupole) {
1004 pref = pre24_ * *(idat.electroMult);
1005 DadQb = D_a * Q_b;
1006 DadQbr = dot(D_a, Qbr);
1007 DaxQbr = cross(D_a, Qbr);
1008
1009 U -= pref * ((trQb*rdDa + 2.0*DadQbr)*v31 + rdDa*rdQbr*v32);
1010 F -= pref * (trQb*D_a + 2.0*DadQb) * v31or;
1011 F -= pref * (trQb*rdDa + 2.0*DadQbr) * (dv31-v31or) * rhat;
1012 F -= pref * (D_a*rdQbr + 2.0*rdDa*rQb) * v32or;
1013 F -= pref * (rdDa * rdQbr * rhat * (dv32-3.0*v32or));
1014 Ta += pref * ((-trQb*rxDa + 2.0 * DaxQbr)*v31 - rxDa*rdQbr*v32);
1015 Tb += pref * ((2.0*cross(DadQb, rhat) - 2.0*DaxQbr)*v31
1016 - 2.0*rdDa*rxQbr*v32);
1017 }
1018 }
1019
1020 if (a_is_Quadrupole) {
1021 if (b_is_Charge) {
1022 pref = pre14_ * *(idat.electroMult);
1023 U += C_b * pref * (v21 * trQa + v22 * rdQar);
1024 F += C_b * pref * (trQa * rhat * dv21 + 2.0 * Qar * v22or);
1025 F += C_b * pref * rdQar * rhat * (dv22 - 2.0*v22or);
1026 Ta += C_b * pref * 2.0 * rxQar * v22;
1027
1028 if (b_is_Fluctuating) dUdCb += pref * (v21 * trQa + v22 * rdQar);
1029 }
1030 if (b_is_Dipole) {
1031 pref = pre24_ * *(idat.electroMult);
1032 DbdQa = D_b * Q_a;
1033 DbdQar = dot(D_b, Qar);
1034 DbxQar = cross(D_b, Qar);
1035
1036 U += pref * ((trQa*rdDb + 2.0*DbdQar)*v31 + rdDb*rdQar*v32);
1037 F += pref * (trQa*D_b + 2.0*DbdQa) * v31or;
1038 F += pref * (trQa*rdDb + 2.0*DbdQar) * (dv31-v31or) * rhat;
1039 F += pref * (D_b*rdQar + 2.0*rdDb*rQa) * v32or;
1040 F += pref * (rdDb * rdQar * rhat * (dv32-3.0*v32or));
1041 Ta += pref * ((-2.0*cross(DbdQa, rhat) + 2.0*DbxQar)*v31
1042 + 2.0*rdDb*rxQar*v32);
1043 Tb += pref * ((trQa*rxDb - 2.0 * DbxQar)*v31 + rxDb*rdQar*v32);
1044 }
1045 if (b_is_Quadrupole) {
1046 pref = pre44_ * *(idat.electroMult); // yes
1047 QaQb = Q_a * Q_b;
1048 trQaQb = QaQb.trace();
1049 rQaQb = rhat * QaQb;
1050 QaQbr = QaQb * rhat;
1051 QaxQb = cross(Q_a, Q_b);
1052 rQaQbr = dot(rQa, Qbr);
1053 rQaxQbr = cross(rQa, Qbr);
1054
1055 U += pref * (trQa * trQb + 2.0 * trQaQb) * v41;
1056 U += pref * (trQa * rdQbr + trQb * rdQar + 4.0 * rQaQbr) * v42;
1057 U += pref * (rdQar * rdQbr) * v43;
1058
1059 F += pref * rhat * (trQa * trQb + 2.0 * trQaQb)*dv41;
1060 F += pref*rhat*(trQa*rdQbr + trQb*rdQar + 4.0*rQaQbr)*(dv42-2.0*v42or);
1061 F += pref * rhat * (rdQar * rdQbr)*(dv43 - 4.0*v43or);
1062
1063 F += pref * 2.0 * (trQb*rQa + trQa*rQb) * v42or;
1064 F += pref * 4.0 * (rQaQb + QaQbr) * v42or;
1065 F += pref * 2.0 * (rQa*rdQbr + rdQar*rQb) * v43or;
1066
1067 Ta += pref * (- 4.0 * QaxQb * v41);
1068 Ta += pref * (- 2.0 * trQb * cross(rQa, rhat)
1069 + 4.0 * cross(rhat, QaQbr)
1070 - 4.0 * rQaxQbr) * v42;
1071 Ta += pref * 2.0 * cross(rhat,Qar) * rdQbr * v43;
1072
1073
1074 Tb += pref * (+ 4.0 * QaxQb * v41);
1075 Tb += pref * (- 2.0 * trQa * cross(rQb, rhat)
1076 - 4.0 * cross(rQaQb, rhat)
1077 + 4.0 * rQaxQbr) * v42;
1078 // Possible replacement for line 2 above:
1079 // + 4.0 * cross(rhat, QbQar)
1080
1081 Tb += pref * 2.0 * cross(rhat,Qbr) * rdQar * v43;
1082
1083 }
1084 }
1085
1086 if (idat.doElectricField) {
1087 *(idat.eField1) += Ea * *(idat.electroMult);
1088 *(idat.eField2) += Eb * *(idat.electroMult);
1089 }
1090
1091 if (a_is_Fluctuating) *(idat.dVdFQ1) += dUdCa * *(idat.sw);
1092 if (b_is_Fluctuating) *(idat.dVdFQ2) += dUdCb * *(idat.sw);
1093
1094 if (!idat.excluded) {
1095
1096 *(idat.vpair) += U;
1097 (*(idat.pot))[ELECTROSTATIC_FAMILY] += U * *(idat.sw);
1098 *(idat.f1) += F * *(idat.sw);
1099
1100 if (a_is_Dipole || a_is_Quadrupole)
1101 *(idat.t1) += Ta * *(idat.sw);
1102
1103 if (b_is_Dipole || b_is_Quadrupole)
1104 *(idat.t2) += Tb * *(idat.sw);
1105
1106 } else {
1107
1108 // only accumulate the forces and torques resulting from the
1109 // indirect reaction field terms.
1110
1111 *(idat.vpair) += indirect_Pot;
1112 (*(idat.excludedPot))[ELECTROSTATIC_FAMILY] += excluded_Pot;
1113 (*(idat.pot))[ELECTROSTATIC_FAMILY] += *(idat.sw) * indirect_Pot;
1114 *(idat.f1) += *(idat.sw) * indirect_F;
1115
1116 if (a_is_Dipole || a_is_Quadrupole)
1117 *(idat.t1) += *(idat.sw) * indirect_Ta;
1118
1119 if (b_is_Dipole || b_is_Quadrupole)
1120 *(idat.t2) += *(idat.sw) * indirect_Tb;
1121 }
1122 return;
1123 }
1124
1125 void Electrostatic::calcSelfCorrection(SelfData &sdat) {
1126
1127 if (!initialized_) initialize();
1128
1129 ElectrostaticAtomData data = ElectrostaticMap[Etids[sdat.atid]];
1130
1131 // logicals
1132 bool i_is_Charge = data.is_Charge;
1133 bool i_is_Dipole = data.is_Dipole;
1134 bool i_is_Quadrupole = data.is_Quadrupole;
1135 bool i_is_Fluctuating = data.is_Fluctuating;
1136 RealType C_a = data.fixedCharge;
1137 RealType self(0.0), preVal, DdD, trQ, trQQ;
1138
1139 if (i_is_Dipole) {
1140 DdD = data.dipole.lengthSquare();
1141 }
1142
1143 if (i_is_Fluctuating) {
1144 C_a += *(sdat.flucQ);
1145 // dVdFQ is really a force, so this is negative the derivative
1146 *(sdat.dVdFQ) -= *(sdat.flucQ) * data.hardness + data.electronegativity;
1147 (*(sdat.excludedPot))[ELECTROSTATIC_FAMILY] += (*sdat.flucQ) *
1148 (*(sdat.flucQ) * data.hardness * 0.5 + data.electronegativity);
1149 }
1150
1151 switch (summationMethod_) {
1152 case esm_REACTION_FIELD:
1153
1154 if (i_is_Charge) {
1155 // Self potential [see Wang and Hermans, "Reaction Field
1156 // Molecular Dynamics Simulation with Friedman’s Image Charge
1157 // Method," J. Phys. Chem. 99, 12001-12007 (1995).]
1158 preVal = pre11_ * preRF_ * C_a * C_a;
1159 (*(sdat.pot))[ELECTROSTATIC_FAMILY] -= 0.5 * preVal / cutoffRadius_;
1160 }
1161
1162 if (i_is_Dipole) {
1163 (*(sdat.pot))[ELECTROSTATIC_FAMILY] -= pre22_ * preRF_ * DdD;
1164 }
1165
1166 break;
1167
1168 case esm_SHIFTED_FORCE:
1169 case esm_SHIFTED_POTENTIAL:
1170 case esm_TAYLOR_SHIFTED:
1171 case esm_EWALD_FULL:
1172 if (i_is_Charge)
1173 self += selfMult1_ * pre11_ * C_a * (C_a + *(sdat.skippedCharge));
1174 if (i_is_Dipole)
1175 self += selfMult2_ * pre22_ * DdD;
1176 if (i_is_Quadrupole) {
1177 trQ = data.quadrupole.trace();
1178 trQQ = (data.quadrupole * data.quadrupole).trace();
1179 self += selfMult4_ * pre44_ * (2.0*trQQ + trQ*trQ);
1180 if (i_is_Charge)
1181 self -= selfMult2_ * pre14_ * 2.0 * C_a * trQ;
1182 }
1183 (*(sdat.pot))[ELECTROSTATIC_FAMILY] += self;
1184 break;
1185 default:
1186 break;
1187 }
1188 }
1189
1190 RealType Electrostatic::getSuggestedCutoffRadius(pair<AtomType*, AtomType*> atypes) {
1191 // This seems to work moderately well as a default. There's no
1192 // inherent scale for 1/r interactions that we can standardize.
1193 // 12 angstroms seems to be a reasonably good guess for most
1194 // cases.
1195 return 12.0;
1196 }
1197
1198
1199 void Electrostatic::ReciprocalSpaceSum(RealType& pot) {
1200
1201 RealType kPot = 0.0;
1202 RealType kVir = 0.0;
1203
1204 const RealType mPoleConverter = 0.20819434; // converts from the
1205 // internal units of
1206 // Debye (for dipoles)
1207 // or Debye-angstroms
1208 // (for quadrupoles) to
1209 // electron angstroms or
1210 // electron-angstroms^2
1211
1212 const RealType eConverter = 332.0637778; // convert the
1213 // Charge-Charge
1214 // electrostatic
1215 // interactions into kcal /
1216 // mol assuming distances
1217 // are measured in
1218 // angstroms.
1219
1220 Mat3x3d hmat = info_->getSnapshotManager()->getCurrentSnapshot()->getHmat();
1221 Vector3d box = hmat.diagonals();
1222 RealType boxMax = box.max();
1223
1224 //int kMax = int(2.0 * M_PI / (pow(dampingAlpha_,2)*cutoffRadius_ * boxMax) );
1225 int kMax = 7;
1226 int kSqMax = kMax*kMax + 2;
1227
1228 int kLimit = kMax+1;
1229 int kLim2 = 2*kMax+1;
1230 int kSqLim = kSqMax;
1231
1232 vector<RealType> AK(kSqLim+1, 0.0);
1233 RealType xcl = 2.0 * M_PI / box.x();
1234 RealType ycl = 2.0 * M_PI / box.y();
1235 RealType zcl = 2.0 * M_PI / box.z();
1236 RealType rcl = 2.0 * M_PI / boxMax;
1237 RealType rvol = 2.0 * M_PI /(box.x() * box.y() * box.z());
1238
1239 if(dampingAlpha_ < 1.0e-12) return;
1240
1241 RealType ralph = -0.25/pow(dampingAlpha_,2);
1242
1243 // Calculate and store exponential factors
1244
1245 vector<vector<RealType> > elc;
1246 vector<vector<RealType> > emc;
1247 vector<vector<RealType> > enc;
1248 vector<vector<RealType> > els;
1249 vector<vector<RealType> > ems;
1250 vector<vector<RealType> > ens;
1251
1252
1253 int nMax = info_->getNAtoms();
1254
1255 elc.resize(kLimit+1);
1256 emc.resize(kLimit+1);
1257 enc.resize(kLimit+1);
1258 els.resize(kLimit+1);
1259 ems.resize(kLimit+1);
1260 ens.resize(kLimit+1);
1261
1262 for (int j = 0; j < kLimit+1; j++) {
1263 elc[j].resize(nMax);
1264 emc[j].resize(nMax);
1265 enc[j].resize(nMax);
1266 els[j].resize(nMax);
1267 ems[j].resize(nMax);
1268 ens[j].resize(nMax);
1269 }
1270
1271 Vector3d t( 2.0 * M_PI );
1272 t.Vdiv(t, box);
1273
1274
1275 SimInfo::MoleculeIterator mi;
1276 Molecule::AtomIterator ai;
1277 int i;
1278 Vector3d r;
1279 Vector3d tt;
1280
1281 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1282 mol = info_->nextMolecule(mi)) {
1283 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1284 atom = mol->nextAtom(ai)) {
1285
1286 i = atom->getLocalIndex();
1287 r = atom->getPos();
1288 info_->getSnapshotManager()->getCurrentSnapshot()->wrapVector(r);
1289
1290 tt.Vmul(t, r);
1291
1292 elc[1][i] = 1.0;
1293 emc[1][i] = 1.0;
1294 enc[1][i] = 1.0;
1295 els[1][i] = 0.0;
1296 ems[1][i] = 0.0;
1297 ens[1][i] = 0.0;
1298
1299 elc[2][i] = cos(tt.x());
1300 emc[2][i] = cos(tt.y());
1301 enc[2][i] = cos(tt.z());
1302 els[2][i] = sin(tt.x());
1303 ems[2][i] = sin(tt.y());
1304 ens[2][i] = sin(tt.z());
1305
1306 for(int l = 3; l <= kLimit; l++) {
1307 elc[l][i]=elc[l-1][i]*elc[2][i]-els[l-1][i]*els[2][i];
1308 emc[l][i]=emc[l-1][i]*emc[2][i]-ems[l-1][i]*ems[2][i];
1309 enc[l][i]=enc[l-1][i]*enc[2][i]-ens[l-1][i]*ens[2][i];
1310 els[l][i]=els[l-1][i]*elc[2][i]+elc[l-1][i]*els[2][i];
1311 ems[l][i]=ems[l-1][i]*emc[2][i]+emc[l-1][i]*ems[2][i];
1312 ens[l][i]=ens[l-1][i]*enc[2][i]+enc[l-1][i]*ens[2][i];
1313 }
1314 }
1315 }
1316
1317 // Calculate and store AK coefficients:
1318
1319 RealType eksq = 1.0;
1320 RealType expf = 0.0;
1321 if (ralph < 0.0) expf = exp(ralph*rcl*rcl);
1322 for (i = 1; i <= kSqLim; i++) {
1323 RealType rksq = float(i)*rcl*rcl;
1324 eksq = expf*eksq;
1325 AK[i] = eConverter * eksq/rksq;
1326 }
1327
1328 /*
1329 * Loop over all k vectors k = 2 pi (ll/Lx, mm/Ly, nn/Lz)
1330 * the values of ll, mm and nn are selected so that the symmetry of
1331 * reciprocal lattice is taken into account i.e. the following
1332 * rules apply.
1333 *
1334 * ll ranges over the values 0 to kMax only.
1335 *
1336 * mm ranges over 0 to kMax when ll=0 and over
1337 * -kMax to kMax otherwise.
1338 * nn ranges over 1 to kMax when ll=mm=0 and over
1339 * -kMax to kMax otherwise.
1340 *
1341 * Hence the result of the summation must be doubled at the end.
1342 */
1343
1344 std::vector<RealType> clm(nMax, 0.0);
1345 std::vector<RealType> slm(nMax, 0.0);
1346 std::vector<RealType> ckr(nMax, 0.0);
1347 std::vector<RealType> skr(nMax, 0.0);
1348 std::vector<RealType> ckc(nMax, 0.0);
1349 std::vector<RealType> cks(nMax, 0.0);
1350 std::vector<RealType> dkc(nMax, 0.0);
1351 std::vector<RealType> dks(nMax, 0.0);
1352 std::vector<RealType> qkc(nMax, 0.0);
1353 std::vector<RealType> qks(nMax, 0.0);
1354 std::vector<Vector3d> dxk(nMax, V3Zero);
1355 std::vector<Vector3d> qxk(nMax, V3Zero);
1356 RealType rl, rm, rn;
1357 Vector3d kVec;
1358 Vector3d Qk;
1359 Mat3x3d k2;
1360 RealType ckcs, ckss, dkcs, dkss, qkcs, qkss;
1361 int atid;
1362 ElectrostaticAtomData data;
1363 RealType C, dk, qk;
1364 Vector3d D;
1365 Mat3x3d Q;
1366
1367 int mMin = kLimit;
1368 int nMin = kLimit + 1;
1369 for (int l = 1; l <= kLimit; l++) {
1370 int ll = l - 1;
1371 rl = xcl * float(ll);
1372 for (int mmm = mMin; mmm <= kLim2; mmm++) {
1373 int mm = mmm - kLimit;
1374 int m = abs(mm) + 1;
1375 rm = ycl * float(mm);
1376 // Set temporary products of exponential terms
1377 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1378 mol = info_->nextMolecule(mi)) {
1379 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1380 atom = mol->nextAtom(ai)) {
1381
1382 i = atom->getLocalIndex();
1383 if(mm < 0) {
1384 clm[i]=elc[l][i]*emc[m][i]+els[l][i]*ems[m][i];
1385 slm[i]=els[l][i]*emc[m][i]-ems[m][i]*elc[l][i];
1386 } else {
1387 clm[i]=elc[l][i]*emc[m][i]-els[l][i]*ems[m][i];
1388 slm[i]=els[l][i]*emc[m][i]+ems[m][i]*elc[l][i];
1389 }
1390 }
1391 }
1392 for (int nnn = nMin; nnn <= kLim2; nnn++) {
1393 int nn = nnn - kLimit;
1394 int n = abs(nn) + 1;
1395 rn = zcl * float(nn);
1396 // Test on magnitude of k vector:
1397 int kk=ll*ll + mm*mm + nn*nn;
1398 if(kk <= kSqLim) {
1399 kVec = Vector3d(rl, rm, rn);
1400 k2 = outProduct(kVec, kVec);
1401 // Calculate exp(ikr) terms
1402 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1403 mol = info_->nextMolecule(mi)) {
1404 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1405 atom = mol->nextAtom(ai)) {
1406 i = atom->getLocalIndex();
1407
1408 if (nn < 0) {
1409 ckr[i]=clm[i]*enc[n][i]+slm[i]*ens[n][i];
1410 skr[i]=slm[i]*enc[n][i]-clm[i]*ens[n][i];
1411
1412 } else {
1413 ckr[i]=clm[i]*enc[n][i]-slm[i]*ens[n][i];
1414 skr[i]=slm[i]*enc[n][i]+clm[i]*ens[n][i];
1415 }
1416 }
1417 }
1418
1419 // Calculate scalar and vector products for each site:
1420
1421 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1422 mol = info_->nextMolecule(mi)) {
1423 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1424 atom = mol->nextAtom(ai)) {
1425 i = atom->getLocalIndex();
1426 int atid = atom->getAtomType()->getIdent();
1427 data = ElectrostaticMap[Etids[atid]];
1428
1429 if (data.is_Charge) {
1430 C = data.fixedCharge;
1431 if (atom->isFluctuatingCharge()) C += atom->getFlucQPos();
1432 ckc[i] = C * ckr[i];
1433 cks[i] = C * skr[i];
1434 }
1435
1436 if (data.is_Dipole) {
1437 D = atom->getDipole() * mPoleConverter;
1438 dk = dot(D, kVec);
1439 dxk[i] = cross(D, kVec);
1440 dkc[i] = dk * ckr[i];
1441 dks[i] = dk * skr[i];
1442 }
1443 if (data.is_Quadrupole) {
1444 Q = atom->getQuadrupole();
1445 Q *= mPoleConverter;
1446 Qk = Q * kVec;
1447 qk = dot(kVec, Qk);
1448 qxk[i] = cross(kVec, Qk);
1449 qkc[i] = qk * ckr[i];
1450 qks[i] = qk * skr[i];
1451 }
1452 }
1453 }
1454
1455 // calculate vector sums
1456
1457 ckcs = std::accumulate(ckc.begin(),ckc.end(),0.0);
1458 ckss = std::accumulate(cks.begin(),cks.end(),0.0);
1459 dkcs = std::accumulate(dkc.begin(),dkc.end(),0.0);
1460 dkss = std::accumulate(dks.begin(),dks.end(),0.0);
1461 qkcs = std::accumulate(qkc.begin(),qkc.end(),0.0);
1462 qkss = std::accumulate(qks.begin(),qks.end(),0.0);
1463
1464 #ifdef IS_MPI
1465 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &ckcs, 1, MPI::REALTYPE,
1466 MPI::SUM);
1467 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &ckss, 1, MPI::REALTYPE,
1468 MPI::SUM);
1469 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &dkcs, 1, MPI::REALTYPE,
1470 MPI::SUM);
1471 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &dkss, 1, MPI::REALTYPE,
1472 MPI::SUM);
1473 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &qkcs, 1, MPI::REALTYPE,
1474 MPI::SUM);
1475 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &qkss, 1, MPI::REALTYPE,
1476 MPI::SUM);
1477 #endif
1478
1479 // Accumulate potential energy and virial contribution:
1480
1481 kPot += 2.0 * rvol * AK[kk]*((ckss+dkcs-qkss)*(ckss+dkcs-qkss)
1482 + (ckcs-dkss-qkcs)*(ckcs-dkss-qkcs));
1483
1484 kVir += 2.0 * rvol * AK[kk]*(ckcs*ckcs+ckss*ckss
1485 +4.0*(ckss*dkcs-ckcs*dkss)
1486 +3.0*(dkcs*dkcs+dkss*dkss)
1487 -6.0*(ckss*qkss+ckcs*qkcs)
1488 +8.0*(dkss*qkcs-dkcs*qkss)
1489 +5.0*(qkss*qkss+qkcs*qkcs));
1490
1491 // Calculate force and torque for each site:
1492
1493 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1494 mol = info_->nextMolecule(mi)) {
1495 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1496 atom = mol->nextAtom(ai)) {
1497
1498 i = atom->getLocalIndex();
1499 atid = atom->getAtomType()->getIdent();
1500 data = ElectrostaticMap[Etids[atid]];
1501
1502 RealType qfrc = AK[kk]*((cks[i]+dkc[i]-qks[i])*(ckcs-dkss-qkcs)
1503 - (ckc[i]-dks[i]-qkc[i])*(ckss+dkcs-qkss));
1504 RealType qtrq1 = AK[kk]*(skr[i]*(ckcs-dkss-qkcs)
1505 -ckr[i]*(ckss+dkcs-qkss));
1506 RealType qtrq2 = 2.0*AK[kk]*(ckr[i]*(ckcs-dkss-qkcs)
1507 +skr[i]*(ckss+dkcs-qkss));
1508
1509 atom->addFrc( 4.0 * rvol * qfrc * kVec );
1510
1511 if (data.is_Dipole) {
1512 atom->addTrq( 4.0 * rvol * qtrq1 * dxk[i] );
1513 }
1514 if (data.is_Quadrupole) {
1515 atom->addTrq( 4.0 * rvol * qtrq2 * qxk[i] );
1516 }
1517 }
1518 }
1519 }
1520 }
1521 nMin = 1;
1522 }
1523 mMin = 1;
1524 }
1525 pot += kPot;
1526 }
1527 }

Properties

Name Value
svn:eol-style native