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root/group/trunk/OOPSE/libmdtools/Integrator.cpp
Revision: 768
Committed: Wed Sep 17 14:22:15 2003 UTC (20 years, 9 months ago) by mmeineke
File size: 16481 byte(s)
Log Message:
fixed NPTi to now work with constraints.

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
258
259
260 #ifdef IS_MPI
261 strcpy(checkPointMsg, "Succesful moveA\n");
262 MPIcheckPoint();
263 #endif // is_mpi
264
265
266 // calc forces
267
268 calcForce(calcPot, calcStress);
269
270 #ifdef IS_MPI
271 strcpy(checkPointMsg, "Succesful doForces\n");
272 MPIcheckPoint();
273 #endif // is_mpi
274
275
276 // finish the velocity half step
277
278 moveB();
279
280
281
282 #ifdef IS_MPI
283 strcpy(checkPointMsg, "Succesful moveB\n");
284 MPIcheckPoint();
285 #endif // is_mpi
286 }
287
288
289 template<typename T> void Integrator<T>::moveA(void){
290 int i, j;
291 DirectionalAtom* dAtom;
292 double Tb[3], ji[3];
293 double A[3][3], I[3][3];
294 double angle;
295 double vel[3], pos[3], frc[3];
296 double mass;
297
298 for (i = 0; i < nAtoms; i++){
299 atoms[i]->getVel(vel);
300 atoms[i]->getPos(pos);
301 atoms[i]->getFrc(frc);
302
303 mass = atoms[i]->getMass();
304
305 for (j = 0; j < 3; j++){
306 // velocity half step
307 vel[j] += (dt2 * frc[j] / mass) * eConvert;
308 // position whole step
309 pos[j] += dt * vel[j];
310 }
311
312 atoms[i]->setVel(vel);
313 atoms[i]->setPos(pos);
314
315 if (atoms[i]->isDirectional()){
316 dAtom = (DirectionalAtom *) atoms[i];
317
318 // get and convert the torque to body frame
319
320 dAtom->getTrq(Tb);
321 dAtom->lab2Body(Tb);
322
323 // get the angular momentum, and propagate a half step
324
325 dAtom->getJ(ji);
326
327 for (j = 0; j < 3; j++)
328 ji[j] += (dt2 * Tb[j]) * eConvert;
329
330 // use the angular velocities to propagate the rotation matrix a
331 // full time step
332
333 dAtom->getA(A);
334 dAtom->getI(I);
335
336 // rotate about the x-axis
337 angle = dt2 * ji[0] / I[0][0];
338 this->rotate(1, 2, angle, ji, A);
339
340 // rotate about the y-axis
341 angle = dt2 * ji[1] / I[1][1];
342 this->rotate(2, 0, angle, ji, A);
343
344 // rotate about the z-axis
345 angle = dt * ji[2] / I[2][2];
346 this->rotate(0, 1, angle, ji, A);
347
348 // rotate about the y-axis
349 angle = dt2 * ji[1] / I[1][1];
350 this->rotate(2, 0, angle, ji, A);
351
352 // rotate about the x-axis
353 angle = dt2 * ji[0] / I[0][0];
354 this->rotate(1, 2, angle, ji, A);
355
356 dAtom->setJ(ji);
357 dAtom->setA(A);
358 }
359 }
360
361 if (nConstrained){
362 constrainA();
363 }
364 }
365
366
367 template<typename T> void Integrator<T>::moveB(void){
368 int i, j;
369 DirectionalAtom* dAtom;
370 double Tb[3], ji[3];
371 double vel[3], frc[3];
372 double mass;
373
374 for (i = 0; i < nAtoms; i++){
375 atoms[i]->getVel(vel);
376 atoms[i]->getFrc(frc);
377
378 mass = atoms[i]->getMass();
379
380 // velocity half step
381 for (j = 0; j < 3; j++)
382 vel[j] += (dt2 * frc[j] / mass) * eConvert;
383
384 atoms[i]->setVel(vel);
385
386 if (atoms[i]->isDirectional()){
387 dAtom = (DirectionalAtom *) atoms[i];
388
389 // get and convert the torque to body frame
390
391 dAtom->getTrq(Tb);
392 dAtom->lab2Body(Tb);
393
394 // get the angular momentum, and propagate a half step
395
396 dAtom->getJ(ji);
397
398 for (j = 0; j < 3; j++)
399 ji[j] += (dt2 * Tb[j]) * eConvert;
400
401
402 dAtom->setJ(ji);
403 }
404 }
405
406 if (nConstrained){
407 constrainB();
408 }
409 }
410
411 template<typename T> void Integrator<T>::preMove(void){
412 int i, j;
413 double pos[3];
414
415 if (nConstrained){
416 for (i = 0; i < nAtoms; i++){
417 atoms[i]->getPos(pos);
418
419 for (j = 0; j < 3; j++){
420 oldPos[3 * i + j] = pos[j];
421 }
422 }
423 }
424 }
425
426 template<typename T> void Integrator<T>::constrainA(){
427 int i, j, k;
428 int done;
429 double posA[3], posB[3];
430 double velA[3], velB[3];
431 double pab[3];
432 double rab[3];
433 int a, b, ax, ay, az, bx, by, bz;
434 double rma, rmb;
435 double dx, dy, dz;
436 double rpab;
437 double rabsq, pabsq, rpabsq;
438 double diffsq;
439 double gab;
440 int iteration;
441
442 for (i = 0; i < nAtoms; i++){
443 moving[i] = 0;
444 moved[i] = 1;
445 }
446
447 iteration = 0;
448 done = 0;
449 while (!done && (iteration < maxIteration)){
450 done = 1;
451 for (i = 0; i < nConstrained; i++){
452 a = constrainedA[i];
453 b = constrainedB[i];
454
455 ax = (a * 3) + 0;
456 ay = (a * 3) + 1;
457 az = (a * 3) + 2;
458
459 bx = (b * 3) + 0;
460 by = (b * 3) + 1;
461 bz = (b * 3) + 2;
462
463 if (moved[a] || moved[b]){
464 atoms[a]->getPos(posA);
465 atoms[b]->getPos(posB);
466
467 for (j = 0; j < 3; j++)
468 pab[j] = posA[j] - posB[j];
469
470 //periodic boundary condition
471
472 info->wrapVector(pab);
473
474 pabsq = pab[0] * pab[0] + pab[1] * pab[1] + pab[2] * pab[2];
475
476 rabsq = constrainedDsqr[i];
477 diffsq = rabsq - pabsq;
478
479 // the original rattle code from alan tidesley
480 if (fabs(diffsq) > (tol * rabsq * 2)){
481 rab[0] = oldPos[ax] - oldPos[bx];
482 rab[1] = oldPos[ay] - oldPos[by];
483 rab[2] = oldPos[az] - oldPos[bz];
484
485 info->wrapVector(rab);
486
487 rpab = rab[0] * pab[0] + rab[1] * pab[1] + rab[2] * pab[2];
488
489 rpabsq = rpab * rpab;
490
491
492 if (rpabsq < (rabsq * -diffsq)){
493 #ifdef IS_MPI
494 a = atoms[a]->getGlobalIndex();
495 b = atoms[b]->getGlobalIndex();
496 #endif //is_mpi
497 sprintf(painCave.errMsg,
498 "Constraint failure in constrainA at atom %d and %d.\n", a,
499 b);
500 painCave.isFatal = 1;
501 simError();
502 }
503
504 rma = 1.0 / atoms[a]->getMass();
505 rmb = 1.0 / atoms[b]->getMass();
506
507 gab = diffsq / (2.0 * (rma + rmb) * rpab);
508
509 dx = rab[0] * gab;
510 dy = rab[1] * gab;
511 dz = rab[2] * gab;
512
513 posA[0] += rma * dx;
514 posA[1] += rma * dy;
515 posA[2] += rma * dz;
516
517 atoms[a]->setPos(posA);
518
519 posB[0] -= rmb * dx;
520 posB[1] -= rmb * dy;
521 posB[2] -= rmb * dz;
522
523 atoms[b]->setPos(posB);
524
525 dx = dx / dt;
526 dy = dy / dt;
527 dz = dz / dt;
528
529 atoms[a]->getVel(velA);
530
531 velA[0] += rma * dx;
532 velA[1] += rma * dy;
533 velA[2] += rma * dz;
534
535 atoms[a]->setVel(velA);
536
537 atoms[b]->getVel(velB);
538
539 velB[0] -= rmb * dx;
540 velB[1] -= rmb * dy;
541 velB[2] -= rmb * dz;
542
543 atoms[b]->setVel(velB);
544
545 moving[a] = 1;
546 moving[b] = 1;
547 done = 0;
548 }
549 }
550 }
551
552 for (i = 0; i < nAtoms; i++){
553 moved[i] = moving[i];
554 moving[i] = 0;
555 }
556
557 iteration++;
558 }
559
560 if (!done){
561 sprintf(painCave.errMsg,
562 "Constraint failure in constrainA, too many iterations: %d\n",
563 iteration);
564 painCave.isFatal = 1;
565 simError();
566 }
567
568 }
569
570 template<typename T> void Integrator<T>::constrainB(void){
571 int i, j, k;
572 int done;
573 double posA[3], posB[3];
574 double velA[3], velB[3];
575 double vxab, vyab, vzab;
576 double rab[3];
577 int a, b, ax, ay, az, bx, by, bz;
578 double rma, rmb;
579 double dx, dy, dz;
580 double rabsq, pabsq, rvab;
581 double diffsq;
582 double gab;
583 int iteration;
584
585 for (i = 0; i < nAtoms; i++){
586 moving[i] = 0;
587 moved[i] = 1;
588 }
589
590 done = 0;
591 iteration = 0;
592 while (!done && (iteration < maxIteration)){
593 done = 1;
594
595 for (i = 0; i < nConstrained; i++){
596 a = constrainedA[i];
597 b = constrainedB[i];
598
599 ax = (a * 3) + 0;
600 ay = (a * 3) + 1;
601 az = (a * 3) + 2;
602
603 bx = (b * 3) + 0;
604 by = (b * 3) + 1;
605 bz = (b * 3) + 2;
606
607 if (moved[a] || moved[b]){
608 atoms[a]->getVel(velA);
609 atoms[b]->getVel(velB);
610
611 vxab = velA[0] - velB[0];
612 vyab = velA[1] - velB[1];
613 vzab = velA[2] - velB[2];
614
615 atoms[a]->getPos(posA);
616 atoms[b]->getPos(posB);
617
618 for (j = 0; j < 3; j++)
619 rab[j] = posA[j] - posB[j];
620
621 info->wrapVector(rab);
622
623 rma = 1.0 / atoms[a]->getMass();
624 rmb = 1.0 / atoms[b]->getMass();
625
626 rvab = rab[0] * vxab + rab[1] * vyab + rab[2] * vzab;
627
628 gab = -rvab / ((rma + rmb) * constrainedDsqr[i]);
629
630 if (fabs(gab) > tol){
631 dx = rab[0] * gab;
632 dy = rab[1] * gab;
633 dz = rab[2] * gab;
634
635 velA[0] += rma * dx;
636 velA[1] += rma * dy;
637 velA[2] += rma * dz;
638
639 atoms[a]->setVel(velA);
640
641 velB[0] -= rmb * dx;
642 velB[1] -= rmb * dy;
643 velB[2] -= rmb * dz;
644
645 atoms[b]->setVel(velB);
646
647 moving[a] = 1;
648 moving[b] = 1;
649 done = 0;
650 }
651 }
652 }
653
654 for (i = 0; i < nAtoms; i++){
655 moved[i] = moving[i];
656 moving[i] = 0;
657 }
658
659 iteration++;
660 }
661
662 if (!done){
663 sprintf(painCave.errMsg,
664 "Constraint failure in constrainB, too many iterations: %d\n",
665 iteration);
666 painCave.isFatal = 1;
667 simError();
668 }
669 }
670
671 template<typename T> void Integrator<T>::rotate(int axes1, int axes2,
672 double angle, double ji[3],
673 double A[3][3]){
674 int i, j, k;
675 double sinAngle;
676 double cosAngle;
677 double angleSqr;
678 double angleSqrOver4;
679 double top, bottom;
680 double rot[3][3];
681 double tempA[3][3];
682 double tempJ[3];
683
684 // initialize the tempA
685
686 for (i = 0; i < 3; i++){
687 for (j = 0; j < 3; j++){
688 tempA[j][i] = A[i][j];
689 }
690 }
691
692 // initialize the tempJ
693
694 for (i = 0; i < 3; i++)
695 tempJ[i] = ji[i];
696
697 // initalize rot as a unit matrix
698
699 rot[0][0] = 1.0;
700 rot[0][1] = 0.0;
701 rot[0][2] = 0.0;
702
703 rot[1][0] = 0.0;
704 rot[1][1] = 1.0;
705 rot[1][2] = 0.0;
706
707 rot[2][0] = 0.0;
708 rot[2][1] = 0.0;
709 rot[2][2] = 1.0;
710
711 // use a small angle aproximation for sin and cosine
712
713 angleSqr = angle * angle;
714 angleSqrOver4 = angleSqr / 4.0;
715 top = 1.0 - angleSqrOver4;
716 bottom = 1.0 + angleSqrOver4;
717
718 cosAngle = top / bottom;
719 sinAngle = angle / bottom;
720
721 rot[axes1][axes1] = cosAngle;
722 rot[axes2][axes2] = cosAngle;
723
724 rot[axes1][axes2] = sinAngle;
725 rot[axes2][axes1] = -sinAngle;
726
727 // rotate the momentum acoording to: ji[] = rot[][] * ji[]
728
729 for (i = 0; i < 3; i++){
730 ji[i] = 0.0;
731 for (k = 0; k < 3; k++){
732 ji[i] += rot[i][k] * tempJ[k];
733 }
734 }
735
736 // rotate the Rotation matrix acording to:
737 // A[][] = A[][] * transpose(rot[][])
738
739
740 // NOte for as yet unknown reason, we are performing the
741 // calculation as:
742 // transpose(A[][]) = transpose(A[][]) * transpose(rot[][])
743
744 for (i = 0; i < 3; i++){
745 for (j = 0; j < 3; j++){
746 A[j][i] = 0.0;
747 for (k = 0; k < 3; k++){
748 A[j][i] += tempA[i][k] * rot[j][k];
749 }
750 }
751 }
752 }
753
754 template<typename T> void Integrator<T>::calcForce(int calcPot, int calcStress){
755 myFF->doForces(calcPot, calcStress);
756 }
757
758 template<typename T> void Integrator<T>::thermalize(){
759 tStats->velocitize();
760 }
761
762 template<typename T> double Integrator<T>::getConservedQuantity(void){
763 return tStats->getTotalE();
764 }