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root/group/trunk/OOPSE/libmdtools/Integrator.cpp
Revision: 746
Committed: Thu Sep 4 21:48:35 2003 UTC (20 years, 10 months ago) by mmeineke
File size: 16373 byte(s)
Log Message:
added resetTime to the Global namespace.

added ability to reset the integrators in the NVT and NPT family.

File Contents

# Content
1 #include <iostream>
2 #include <cstdlib>
3 #include <cmath>
4
5 #ifdef IS_MPI
6 #include "mpiSimulation.hpp"
7 #include <unistd.h>
8 #endif //is_mpi
9
10 #include "Integrator.hpp"
11 #include "simError.h"
12
13
14 template<typename T> Integrator<T>::Integrator(SimInfo* theInfo,
15 ForceFields* the_ff){
16 info = theInfo;
17 myFF = the_ff;
18 isFirst = 1;
19
20 molecules = info->molecules;
21 nMols = info->n_mol;
22
23 // give a little love back to the SimInfo object
24
25 if (info->the_integrator != NULL){
26 delete info->the_integrator;
27 }
28 info->the_integrator = this;
29
30 nAtoms = info->n_atoms;
31
32 // check for constraints
33
34 constrainedA = NULL;
35 constrainedB = NULL;
36 constrainedDsqr = NULL;
37 moving = NULL;
38 moved = NULL;
39 oldPos = NULL;
40
41 nConstrained = 0;
42
43 checkConstraints();
44 }
45
46 template<typename T> Integrator<T>::~Integrator(){
47 if (nConstrained){
48 delete[] constrainedA;
49 delete[] constrainedB;
50 delete[] constrainedDsqr;
51 delete[] moving;
52 delete[] moved;
53 delete[] oldPos;
54 }
55 }
56
57 template<typename T> void Integrator<T>::checkConstraints(void){
58 isConstrained = 0;
59
60 Constraint* temp_con;
61 Constraint* dummy_plug;
62 temp_con = new Constraint[info->n_SRI];
63 nConstrained = 0;
64 int constrained = 0;
65
66 SRI** theArray;
67 for (int i = 0; i < nMols; i++){
68 theArray = (SRI * *) molecules[i].getMyBonds();
69 for (int j = 0; j < molecules[i].getNBonds(); j++){
70 constrained = theArray[j]->is_constrained();
71
72 if (constrained){
73 dummy_plug = theArray[j]->get_constraint();
74 temp_con[nConstrained].set_a(dummy_plug->get_a());
75 temp_con[nConstrained].set_b(dummy_plug->get_b());
76 temp_con[nConstrained].set_dsqr(dummy_plug->get_dsqr());
77
78 nConstrained++;
79 constrained = 0;
80 }
81 }
82
83 theArray = (SRI * *) molecules[i].getMyBends();
84 for (int j = 0; j < molecules[i].getNBends(); j++){
85 constrained = theArray[j]->is_constrained();
86
87 if (constrained){
88 dummy_plug = theArray[j]->get_constraint();
89 temp_con[nConstrained].set_a(dummy_plug->get_a());
90 temp_con[nConstrained].set_b(dummy_plug->get_b());
91 temp_con[nConstrained].set_dsqr(dummy_plug->get_dsqr());
92
93 nConstrained++;
94 constrained = 0;
95 }
96 }
97
98 theArray = (SRI * *) molecules[i].getMyTorsions();
99 for (int j = 0; j < molecules[i].getNTorsions(); j++){
100 constrained = theArray[j]->is_constrained();
101
102 if (constrained){
103 dummy_plug = theArray[j]->get_constraint();
104 temp_con[nConstrained].set_a(dummy_plug->get_a());
105 temp_con[nConstrained].set_b(dummy_plug->get_b());
106 temp_con[nConstrained].set_dsqr(dummy_plug->get_dsqr());
107
108 nConstrained++;
109 constrained = 0;
110 }
111 }
112 }
113
114 if (nConstrained > 0){
115 isConstrained = 1;
116
117 if (constrainedA != NULL)
118 delete[] constrainedA;
119 if (constrainedB != NULL)
120 delete[] constrainedB;
121 if (constrainedDsqr != NULL)
122 delete[] constrainedDsqr;
123
124 constrainedA = new int[nConstrained];
125 constrainedB = new int[nConstrained];
126 constrainedDsqr = new double[nConstrained];
127
128 for (int i = 0; i < nConstrained; i++){
129 constrainedA[i] = temp_con[i].get_a();
130 constrainedB[i] = temp_con[i].get_b();
131 constrainedDsqr[i] = temp_con[i].get_dsqr();
132 }
133
134
135 // save oldAtoms to check for lode balanceing later on.
136
137 oldAtoms = nAtoms;
138
139 moving = new int[nAtoms];
140 moved = new int[nAtoms];
141
142 oldPos = new double[nAtoms * 3];
143 }
144
145 delete[] temp_con;
146 }
147
148
149 template<typename T> void Integrator<T>::integrate(void){
150 int i, j; // loop counters
151
152 double runTime = info->run_time;
153 double sampleTime = info->sampleTime;
154 double statusTime = info->statusTime;
155 double thermalTime = info->thermalTime;
156 double resetTime = info->resetTime;
157
158
159 double currSample;
160 double currThermal;
161 double currStatus;
162 double currReset;
163
164 int calcPot, calcStress;
165 int isError;
166
167 tStats = new Thermo(info);
168 statOut = new StatWriter(info);
169 dumpOut = new DumpWriter(info);
170
171 atoms = info->atoms;
172 DirectionalAtom* dAtom;
173
174 dt = info->dt;
175 dt2 = 0.5 * dt;
176
177 // initialize the forces before the first step
178
179 calcForce(1, 1);
180
181 if (info->setTemp){
182 thermalize();
183 }
184
185 calcPot = 0;
186 calcStress = 0;
187 currSample = sampleTime + info->getTime();
188 currThermal = thermalTime+ info->getTime();
189 currStatus = statusTime + info->getTime();
190 currReset = resetTime + info->getTime();
191
192 dumpOut->writeDump(info->getTime());
193 statOut->writeStat(info->getTime());
194
195 readyCheck();
196
197 #ifdef IS_MPI
198 strcpy(checkPointMsg, "The integrator is ready to go.");
199 MPIcheckPoint();
200 #endif // is_mpi
201
202 while (info->getTime() < runTime){
203 if ((info->getTime() + dt) >= currStatus){
204 calcPot = 1;
205 calcStress = 1;
206 }
207
208 integrateStep(calcPot, calcStress);
209
210 info->incrTime(dt);
211
212 if (info->setTemp){
213 if (info->getTime() >= currThermal){
214 thermalize();
215 currThermal += thermalTime;
216 }
217 }
218
219 if (info->getTime() >= currSample){
220 dumpOut->writeDump(info->getTime());
221 currSample += sampleTime;
222 }
223
224 if (info->getTime() >= currStatus){
225 statOut->writeStat(info->getTime());
226 calcPot = 0;
227 calcStress = 0;
228 currStatus += statusTime;
229 }
230
231 if (info->resetIntegrator){
232 if (info->getTime() >= currReset){
233 this->resetIntegrator();
234 currReset += resetTime;
235 }
236 }
237
238 #ifdef IS_MPI
239 strcpy(checkPointMsg, "successfully took a time step.");
240 MPIcheckPoint();
241 #endif // is_mpi
242 }
243
244 dumpOut->writeFinal(info->getTime());
245
246 delete dumpOut;
247 delete statOut;
248 }
249
250 template<typename T> void Integrator<T>::integrateStep(int calcPot,
251 int calcStress){
252 // Position full step, and velocity half step
253 preMove();
254
255 moveA();
256
257 if (nConstrained){
258 constrainA();
259 }
260
261
262 #ifdef IS_MPI
263 strcpy(checkPointMsg, "Succesful moveA\n");
264 MPIcheckPoint();
265 #endif // is_mpi
266
267
268 // calc forces
269
270 calcForce(calcPot, calcStress);
271
272 #ifdef IS_MPI
273 strcpy(checkPointMsg, "Succesful doForces\n");
274 MPIcheckPoint();
275 #endif // is_mpi
276
277
278 // finish the velocity half step
279
280 moveB();
281
282 if (nConstrained){
283 constrainB();
284 }
285
286 #ifdef IS_MPI
287 strcpy(checkPointMsg, "Succesful moveB\n");
288 MPIcheckPoint();
289 #endif // is_mpi
290 }
291
292
293 template<typename T> void Integrator<T>::moveA(void){
294 int i, j;
295 DirectionalAtom* dAtom;
296 double Tb[3], ji[3];
297 double A[3][3], I[3][3];
298 double angle;
299 double vel[3], pos[3], frc[3];
300 double mass;
301
302 for (i = 0; i < nAtoms; i++){
303 atoms[i]->getVel(vel);
304 atoms[i]->getPos(pos);
305 atoms[i]->getFrc(frc);
306
307 mass = atoms[i]->getMass();
308
309 for (j = 0; j < 3; j++){
310 // velocity half step
311 vel[j] += (dt2 * frc[j] / mass) * eConvert;
312 // position whole step
313 pos[j] += dt * vel[j];
314 }
315
316 atoms[i]->setVel(vel);
317 atoms[i]->setPos(pos);
318
319 if (atoms[i]->isDirectional()){
320 dAtom = (DirectionalAtom *) atoms[i];
321
322 // get and convert the torque to body frame
323
324 dAtom->getTrq(Tb);
325 dAtom->lab2Body(Tb);
326
327 // get the angular momentum, and propagate a half step
328
329 dAtom->getJ(ji);
330
331 for (j = 0; j < 3; j++)
332 ji[j] += (dt2 * Tb[j]) * eConvert;
333
334 // use the angular velocities to propagate the rotation matrix a
335 // full time step
336
337 dAtom->getA(A);
338 dAtom->getI(I);
339
340 // rotate about the x-axis
341 angle = dt2 * ji[0] / I[0][0];
342 this->rotate(1, 2, angle, ji, A);
343
344 // rotate about the y-axis
345 angle = dt2 * ji[1] / I[1][1];
346 this->rotate(2, 0, angle, ji, A);
347
348 // rotate about the z-axis
349 angle = dt * ji[2] / I[2][2];
350 this->rotate(0, 1, angle, ji, A);
351
352 // rotate about the y-axis
353 angle = dt2 * ji[1] / I[1][1];
354 this->rotate(2, 0, angle, ji, A);
355
356 // rotate about the x-axis
357 angle = dt2 * ji[0] / I[0][0];
358 this->rotate(1, 2, angle, ji, A);
359
360
361 dAtom->setJ(ji);
362 dAtom->setA(A);
363 }
364 }
365 }
366
367
368 template<typename T> void Integrator<T>::moveB(void){
369 int i, j;
370 DirectionalAtom* dAtom;
371 double Tb[3], ji[3];
372 double vel[3], frc[3];
373 double mass;
374
375 for (i = 0; i < nAtoms; i++){
376 atoms[i]->getVel(vel);
377 atoms[i]->getFrc(frc);
378
379 mass = atoms[i]->getMass();
380
381 // velocity half step
382 for (j = 0; j < 3; j++)
383 vel[j] += (dt2 * frc[j] / mass) * eConvert;
384
385 atoms[i]->setVel(vel);
386
387 if (atoms[i]->isDirectional()){
388 dAtom = (DirectionalAtom *) atoms[i];
389
390 // get and convert the torque to body frame
391
392 dAtom->getTrq(Tb);
393 dAtom->lab2Body(Tb);
394
395 // get the angular momentum, and propagate a half step
396
397 dAtom->getJ(ji);
398
399 for (j = 0; j < 3; j++)
400 ji[j] += (dt2 * Tb[j]) * eConvert;
401
402
403 dAtom->setJ(ji);
404 }
405 }
406 }
407
408 template<typename T> void Integrator<T>::preMove(void){
409 int i, j;
410 double pos[3];
411
412 if (nConstrained){
413 for (i = 0; i < nAtoms; i++){
414 atoms[i]->getPos(pos);
415
416 for (j = 0; j < 3; j++){
417 oldPos[3 * i + j] = pos[j];
418 }
419 }
420 }
421 }
422
423 template<typename T> void Integrator<T>::constrainA(){
424 int i, j, k;
425 int done;
426 double posA[3], posB[3];
427 double velA[3], velB[3];
428 double pab[3];
429 double rab[3];
430 int a, b, ax, ay, az, bx, by, bz;
431 double rma, rmb;
432 double dx, dy, dz;
433 double rpab;
434 double rabsq, pabsq, rpabsq;
435 double diffsq;
436 double gab;
437 int iteration;
438
439 for (i = 0; i < nAtoms; i++){
440 moving[i] = 0;
441 moved[i] = 1;
442 }
443
444 iteration = 0;
445 done = 0;
446 while (!done && (iteration < maxIteration)){
447 done = 1;
448 for (i = 0; i < nConstrained; i++){
449 a = constrainedA[i];
450 b = constrainedB[i];
451
452 ax = (a * 3) + 0;
453 ay = (a * 3) + 1;
454 az = (a * 3) + 2;
455
456 bx = (b * 3) + 0;
457 by = (b * 3) + 1;
458 bz = (b * 3) + 2;
459
460 if (moved[a] || moved[b]){
461 atoms[a]->getPos(posA);
462 atoms[b]->getPos(posB);
463
464 for (j = 0; j < 3; j++)
465 pab[j] = posA[j] - posB[j];
466
467 //periodic boundary condition
468
469 info->wrapVector(pab);
470
471 pabsq = pab[0] * pab[0] + pab[1] * pab[1] + pab[2] * pab[2];
472
473 rabsq = constrainedDsqr[i];
474 diffsq = rabsq - pabsq;
475
476 // the original rattle code from alan tidesley
477 if (fabs(diffsq) > (tol * rabsq * 2)){
478 rab[0] = oldPos[ax] - oldPos[bx];
479 rab[1] = oldPos[ay] - oldPos[by];
480 rab[2] = oldPos[az] - oldPos[bz];
481
482 info->wrapVector(rab);
483
484 rpab = rab[0] * pab[0] + rab[1] * pab[1] + rab[2] * pab[2];
485
486 rpabsq = rpab * rpab;
487
488
489 if (rpabsq < (rabsq * -diffsq)){
490 #ifdef IS_MPI
491 a = atoms[a]->getGlobalIndex();
492 b = atoms[b]->getGlobalIndex();
493 #endif //is_mpi
494 sprintf(painCave.errMsg,
495 "Constraint failure in constrainA at atom %d and %d.\n", a,
496 b);
497 painCave.isFatal = 1;
498 simError();
499 }
500
501 rma = 1.0 / atoms[a]->getMass();
502 rmb = 1.0 / atoms[b]->getMass();
503
504 gab = diffsq / (2.0 * (rma + rmb) * rpab);
505
506 dx = rab[0] * gab;
507 dy = rab[1] * gab;
508 dz = rab[2] * gab;
509
510 posA[0] += rma * dx;
511 posA[1] += rma * dy;
512 posA[2] += rma * dz;
513
514 atoms[a]->setPos(posA);
515
516 posB[0] -= rmb * dx;
517 posB[1] -= rmb * dy;
518 posB[2] -= rmb * dz;
519
520 atoms[b]->setPos(posB);
521
522 dx = dx / dt;
523 dy = dy / dt;
524 dz = dz / dt;
525
526 atoms[a]->getVel(velA);
527
528 velA[0] += rma * dx;
529 velA[1] += rma * dy;
530 velA[2] += rma * dz;
531
532 atoms[a]->setVel(velA);
533
534 atoms[b]->getVel(velB);
535
536 velB[0] -= rmb * dx;
537 velB[1] -= rmb * dy;
538 velB[2] -= rmb * dz;
539
540 atoms[b]->setVel(velB);
541
542 moving[a] = 1;
543 moving[b] = 1;
544 done = 0;
545 }
546 }
547 }
548
549 for (i = 0; i < nAtoms; i++){
550 moved[i] = moving[i];
551 moving[i] = 0;
552 }
553
554 iteration++;
555 }
556
557 if (!done){
558 sprintf(painCave.errMsg,
559 "Constraint failure in constrainA, too many iterations: %d\n",
560 iteration);
561 painCave.isFatal = 1;
562 simError();
563 }
564 }
565
566 template<typename T> void Integrator<T>::constrainB(void){
567 int i, j, k;
568 int done;
569 double posA[3], posB[3];
570 double velA[3], velB[3];
571 double vxab, vyab, vzab;
572 double rab[3];
573 int a, b, ax, ay, az, bx, by, bz;
574 double rma, rmb;
575 double dx, dy, dz;
576 double rabsq, pabsq, rvab;
577 double diffsq;
578 double gab;
579 int iteration;
580
581 for (i = 0; i < nAtoms; i++){
582 moving[i] = 0;
583 moved[i] = 1;
584 }
585
586 done = 0;
587 iteration = 0;
588 while (!done && (iteration < maxIteration)){
589 done = 1;
590
591 for (i = 0; i < nConstrained; i++){
592 a = constrainedA[i];
593 b = constrainedB[i];
594
595 ax = (a * 3) + 0;
596 ay = (a * 3) + 1;
597 az = (a * 3) + 2;
598
599 bx = (b * 3) + 0;
600 by = (b * 3) + 1;
601 bz = (b * 3) + 2;
602
603 if (moved[a] || moved[b]){
604 atoms[a]->getVel(velA);
605 atoms[b]->getVel(velB);
606
607 vxab = velA[0] - velB[0];
608 vyab = velA[1] - velB[1];
609 vzab = velA[2] - velB[2];
610
611 atoms[a]->getPos(posA);
612 atoms[b]->getPos(posB);
613
614 for (j = 0; j < 3; j++)
615 rab[j] = posA[j] - posB[j];
616
617 info->wrapVector(rab);
618
619 rma = 1.0 / atoms[a]->getMass();
620 rmb = 1.0 / atoms[b]->getMass();
621
622 rvab = rab[0] * vxab + rab[1] * vyab + rab[2] * vzab;
623
624 gab = -rvab / ((rma + rmb) * constrainedDsqr[i]);
625
626 if (fabs(gab) > tol){
627 dx = rab[0] * gab;
628 dy = rab[1] * gab;
629 dz = rab[2] * gab;
630
631 velA[0] += rma * dx;
632 velA[1] += rma * dy;
633 velA[2] += rma * dz;
634
635 atoms[a]->setVel(velA);
636
637 velB[0] -= rmb * dx;
638 velB[1] -= rmb * dy;
639 velB[2] -= rmb * dz;
640
641 atoms[b]->setVel(velB);
642
643 moving[a] = 1;
644 moving[b] = 1;
645 done = 0;
646 }
647 }
648 }
649
650 for (i = 0; i < nAtoms; i++){
651 moved[i] = moving[i];
652 moving[i] = 0;
653 }
654
655 iteration++;
656 }
657
658 if (!done){
659 sprintf(painCave.errMsg,
660 "Constraint failure in constrainB, too many iterations: %d\n",
661 iteration);
662 painCave.isFatal = 1;
663 simError();
664 }
665 }
666
667 template<typename T> void Integrator<T>::rotate(int axes1, int axes2,
668 double angle, double ji[3],
669 double A[3][3]){
670 int i, j, k;
671 double sinAngle;
672 double cosAngle;
673 double angleSqr;
674 double angleSqrOver4;
675 double top, bottom;
676 double rot[3][3];
677 double tempA[3][3];
678 double tempJ[3];
679
680 // initialize the tempA
681
682 for (i = 0; i < 3; i++){
683 for (j = 0; j < 3; j++){
684 tempA[j][i] = A[i][j];
685 }
686 }
687
688 // initialize the tempJ
689
690 for (i = 0; i < 3; i++)
691 tempJ[i] = ji[i];
692
693 // initalize rot as a unit matrix
694
695 rot[0][0] = 1.0;
696 rot[0][1] = 0.0;
697 rot[0][2] = 0.0;
698
699 rot[1][0] = 0.0;
700 rot[1][1] = 1.0;
701 rot[1][2] = 0.0;
702
703 rot[2][0] = 0.0;
704 rot[2][1] = 0.0;
705 rot[2][2] = 1.0;
706
707 // use a small angle aproximation for sin and cosine
708
709 angleSqr = angle * angle;
710 angleSqrOver4 = angleSqr / 4.0;
711 top = 1.0 - angleSqrOver4;
712 bottom = 1.0 + angleSqrOver4;
713
714 cosAngle = top / bottom;
715 sinAngle = angle / bottom;
716
717 rot[axes1][axes1] = cosAngle;
718 rot[axes2][axes2] = cosAngle;
719
720 rot[axes1][axes2] = sinAngle;
721 rot[axes2][axes1] = -sinAngle;
722
723 // rotate the momentum acoording to: ji[] = rot[][] * ji[]
724
725 for (i = 0; i < 3; i++){
726 ji[i] = 0.0;
727 for (k = 0; k < 3; k++){
728 ji[i] += rot[i][k] * tempJ[k];
729 }
730 }
731
732 // rotate the Rotation matrix acording to:
733 // A[][] = A[][] * transpose(rot[][])
734
735
736 // NOte for as yet unknown reason, we are performing the
737 // calculation as:
738 // transpose(A[][]) = transpose(A[][]) * transpose(rot[][])
739
740 for (i = 0; i < 3; i++){
741 for (j = 0; j < 3; j++){
742 A[j][i] = 0.0;
743 for (k = 0; k < 3; k++){
744 A[j][i] += tempA[i][k] * rot[j][k];
745 }
746 }
747 }
748 }
749
750 template<typename T> void Integrator<T>::calcForce(int calcPot, int calcStress){
751 myFF->doForces(calcPot, calcStress);
752 }
753
754 template<typename T> void Integrator<T>::thermalize(){
755 tStats->velocitize();
756 }