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39 * \brief Defines SHAKE code.
41 * \author David van der Spoel <david.vanderspoel@icm.uu.se>
42 * \author Berk Hess <hess@kth.se>
43 * \author Mark Abraham <mark.j.abraham@gmail.com>
44 * \ingroup module_mdlib
55 #include "gromacs/gmxlib/nrnb.h"
56 #include "gromacs/math/functions.h"
57 #include "gromacs/math/vec.h"
58 #include "gromacs/mdlib/constr.h"
59 #include "gromacs/mdlib/splitter.h"
60 #include "gromacs/mdtypes/inputrec.h"
61 #include "gromacs/mdtypes/md_enums.h"
62 #include "gromacs/pbcutil/pbc.h"
63 #include "gromacs/topology/invblock.h"
64 #include "gromacs/utility/fatalerror.h"
65 #include "gromacs/utility/smalloc.h"
76 //! Compares sort blocks.
77 static int pcomp(const void* p1, const void* p2)
80 int min1, min2, max1, max2;
81 const t_sortblock* a1 = reinterpret_cast<const t_sortblock*>(p1);
82 const t_sortblock* a2 = reinterpret_cast<const t_sortblock*>(p2);
84 db = a1->blocknr - a2->blocknr;
91 min1 = std::min(a1->iatom[1], a1->iatom[2]);
92 max1 = std::max(a1->iatom[1], a1->iatom[2]);
93 min2 = std::min(a2->iatom[1], a2->iatom[2]);
94 max2 = std::max(a2->iatom[1], a2->iatom[2]);
106 //! Prints sortblocks
107 static void pr_sortblock(FILE* fp, const char* title, int nsb, t_sortblock sb[])
111 fprintf(fp, "%s\n", title);
112 for (i = 0; (i < nsb); i++)
115 "i: %5d, iatom: (%5d %5d %5d), blocknr: %5d\n",
124 //! Reallocates a vector.
125 static void resizeLagrangianData(shakedata* shaked, int ncons)
127 shaked->scaled_lagrange_multiplier.resize(ncons);
130 void make_shake_sblock_serial(shakedata* shaked, InteractionDefinitions* idef, const int numAtoms)
138 /* Since we are processing the local topology,
139 * the F_CONSTRNC ilist has been concatenated to the F_CONSTR ilist.
141 ncons = idef->il[F_CONSTR].size() / 3;
143 init_blocka(&sblocks);
144 sfree(sblocks.index); // To solve memory leak
145 gen_sblocks(nullptr, numAtoms, *idef, &sblocks, FALSE);
148 bstart=(idef->nodeid > 0) ? blocks->multinr[idef->nodeid-1] : 0;
149 nblocks=blocks->multinr[idef->nodeid] - bstart;
154 fprintf(debug, "ncons: %d, bstart: %d, nblocks: %d\n", ncons, bstart, sblocks.nr);
157 /* Calculate block number for each atom */
158 inv_sblock = make_invblocka(&sblocks, numAtoms);
160 done_blocka(&sblocks);
162 /* Store the block number in temp array and
163 * sort the constraints in order of the sblock number
164 * and the atom numbers, really sorting a segment of the array!
166 int* iatom = idef->il[F_CONSTR].iatoms.data();
168 for (i = 0; (i < ncons); i++, iatom += 3)
170 for (m = 0; (m < 3); m++)
172 sb[i].iatom[m] = iatom[m];
174 sb[i].blocknr = inv_sblock[iatom[1]];
177 /* Now sort the blocks */
180 pr_sortblock(debug, "Before sorting", ncons, sb);
181 fprintf(debug, "Going to sort constraints\n");
184 std::qsort(sb, ncons, sizeof(*sb), pcomp);
188 pr_sortblock(debug, "After sorting", ncons, sb);
191 iatom = idef->il[F_CONSTR].iatoms.data();
192 for (i = 0; (i < ncons); i++, iatom += 3)
194 for (m = 0; (m < 3); m++)
196 iatom[m] = sb[i].iatom[m];
200 shaked->sblock.clear();
202 for (i = 0; (i < ncons); i++)
204 if (sb[i].blocknr != bnr)
207 shaked->sblock.push_back(3 * i);
211 shaked->sblock.push_back(3 * ncons);
215 resizeLagrangianData(shaked, ncons);
218 void make_shake_sblock_dd(shakedata* shaked, const InteractionList& ilcon)
222 ncons = ilcon.size() / 3;
223 const int* iatom = ilcon.iatoms.data();
224 shaked->sblock.clear();
226 for (c = 0; c < ncons; c++)
228 if (c == 0 || iatom[1] >= cg + 1)
230 shaked->sblock.push_back(3 * c);
231 while (iatom[1] >= cg + 1)
238 shaked->sblock.push_back(3 * ncons);
239 resizeLagrangianData(shaked, ncons);
242 /*! \brief Inner kernel for SHAKE constraints
244 * Original implementation from R.C. van Schaik and W.F. van Gunsteren
245 * (ETH Zuerich, June 1992), adapted for GROMACS by David van der
246 * Spoel November 1992.
248 * The algorithm here is based section five of Ryckaert, Ciccotti and
249 * Berendsen, J Comp Phys, 23, 327, 1977.
251 * \param[in] iatom Mini-topology of triplets of constraint type (unused
252 * in this function) and indices of two atoms involved
253 * \param[in] ncon Number of constraints
254 * \param[out] nnit Number of iterations performed
255 * \param[in] maxnit Maximum number of iterations permitted
256 * \param[in] constraint_distance_squared The objective value for each constraint
257 * \param[inout] positions The initial (and final) values of the positions
259 * \param[in] pbc PBC information
260 * \param[in] initial_displacements The initial displacements of each constraint
261 * \param[in] half_of_reduced_mass Half of the reduced mass for each constraint
262 * \param[in] omega SHAKE over-relaxation factor (set non-1.0 by
263 * using shake-sor=yes in the .mdp,
264 * but there is no documentation anywhere)
265 * \param[in] invmass Inverse mass of each atom
266 * \param[in] distance_squared_tolerance Multiplicative tolerance on the difference in the
267 * square of the constrained distance (see code)
268 * \param[out] scaled_lagrange_multiplier Scaled Lagrange multiplier for each constraint
269 * (-2 * eta from p. 336 of the paper, divided by
270 * the constraint distance)
271 * \param[out] nerror Zero upon success, returns one more than the index of
272 * the problematic constraint if the input was malformed
274 * \todo Make SHAKE use better data structures, in particular for iatom. */
275 void cshake(const int iatom[],
279 ArrayRef<const real> constraint_distance_squared,
280 ArrayRef<RVec> positions,
282 ArrayRef<const RVec> initial_displacements,
283 ArrayRef<const real> half_of_reduced_mass,
285 const real invmass[],
286 ArrayRef<const real> distance_squared_tolerance,
287 ArrayRef<real> scaled_lagrange_multiplier,
290 /* default should be increased! MRS 8/4/2009 */
291 const real mytol = 1e-10;
293 // TODO nconv is used solely as a boolean, so we should write the
298 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
301 for (int ll = 0; (ll < ncon) && (error == 0); ll++)
303 const int l3 = 3 * ll;
304 const real rijx = initial_displacements[ll][XX];
305 const real rijy = initial_displacements[ll][YY];
306 const real rijz = initial_displacements[ll][ZZ];
307 const int i = iatom[l3 + 1];
308 const int j = iatom[l3 + 2];
310 /* Compute r prime between atoms i and j, which is the
311 displacement *before* this update stage */
315 pbc_dx(pbc, positions[i], positions[j], r_prime);
319 rvec_sub(positions[i], positions[j], r_prime);
321 const real r_prime_squared = norm2(r_prime);
322 const real constraint_distance_squared_ll = constraint_distance_squared[ll];
323 const real diff = constraint_distance_squared_ll - r_prime_squared;
325 /* iconvf is less than 1 when the error is smaller than a bound */
326 const real iconvf = std::abs(diff) * distance_squared_tolerance[ll];
328 if (iconvf > 1.0_real)
330 nconv = static_cast<int>(iconvf);
331 const real r_dot_r_prime =
332 (rijx * r_prime[XX] + rijy * r_prime[YY] + rijz * r_prime[ZZ]);
334 if (r_dot_r_prime < constraint_distance_squared_ll * mytol)
340 /* The next line solves equation 5.6 (neglecting
341 the term in g^2), for g */
342 real scaled_lagrange_multiplier_ll =
343 omega * diff * half_of_reduced_mass[ll] / r_dot_r_prime;
344 scaled_lagrange_multiplier[ll] += scaled_lagrange_multiplier_ll;
345 const real xh = rijx * scaled_lagrange_multiplier_ll;
346 const real yh = rijy * scaled_lagrange_multiplier_ll;
347 const real zh = rijz * scaled_lagrange_multiplier_ll;
348 const real im = invmass[i];
349 const real jm = invmass[j];
350 positions[i][XX] += xh * im;
351 positions[i][YY] += yh * im;
352 positions[i][ZZ] += zh * im;
353 positions[j][XX] -= xh * jm;
354 positions[j][YY] -= yh * jm;
355 positions[j][ZZ] -= zh * jm;
364 //! Implements RATTLE (ie. SHAKE for velocity verlet integrators)
365 static void crattle(const int iatom[],
369 ArrayRef<const real> constraint_distance_squared,
371 ArrayRef<const RVec> rij,
372 ArrayRef<const real> m2,
374 const real invmass[],
375 ArrayRef<const real> distance_squared_tolerance,
376 ArrayRef<real> scaled_lagrange_multiplier,
381 * r.c. van schaik and w.f. van gunsteren
384 * Adapted for use with Gromacs by David van der Spoel november 92 and later.
385 * rattle added by M.R. Shirts, April 2004, from code written by Jay Ponder in TINKER
386 * second part of rattle algorithm
389 // TODO nconv is used solely as a boolean, so we should write the
394 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
397 for (int ll = 0; (ll < ncon) && (error == 0); ll++)
399 const int l3 = 3 * ll;
400 const real rijx = rij[ll][XX];
401 const real rijy = rij[ll][YY];
402 const real rijz = rij[ll][ZZ];
403 const int i = iatom[l3 + 1];
404 const int j = iatom[l3 + 2];
406 rvec_sub(vp[i], vp[j], v);
408 const real vpijd = v[XX] * rijx + v[YY] * rijy + v[ZZ] * rijz;
409 const real constraint_distance_squared_ll = constraint_distance_squared[ll];
411 /* iconv is zero when the error is smaller than a bound */
412 const real iconvf = fabs(vpijd) * (distance_squared_tolerance[ll] / invdt);
414 if (iconvf > 1.0_real)
416 nconv = static_cast<int>(iconvf);
417 const real fac = omega * 2.0_real * m2[ll] / constraint_distance_squared_ll;
418 const real acor = -fac * vpijd;
419 scaled_lagrange_multiplier[ll] += acor;
420 const real xh = rijx * acor;
421 const real yh = rijy * acor;
422 const real zh = rijz * acor;
424 const real im = invmass[i];
425 const real jm = invmass[j];
427 vp[i][XX] += xh * im;
428 vp[i][YY] += yh * im;
429 vp[i][ZZ] += zh * im;
430 vp[j][XX] -= xh * jm;
431 vp[j][YY] -= yh * jm;
432 vp[j][ZZ] -= zh * jm;
441 static int vec_shakef(FILE* fplog,
443 const real invmass[],
445 ArrayRef<const t_iparams> ip,
448 ArrayRef<const RVec> x,
449 ArrayRef<RVec> prime,
454 ArrayRef<real> scaled_lagrange_multiplier,
459 ConstraintVariable econq)
462 int nit = 0, ll, i, j, d, d2, type;
465 real constraint_distance;
467 shaked->rij.resize(ncon);
468 shaked->half_of_reduced_mass.resize(ncon);
469 shaked->distance_squared_tolerance.resize(ncon);
470 shaked->constraint_distance_squared.resize(ncon);
472 ArrayRef<RVec> rij = shaked->rij;
473 ArrayRef<real> half_of_reduced_mass = shaked->half_of_reduced_mass;
474 ArrayRef<real> distance_squared_tolerance = shaked->distance_squared_tolerance;
475 ArrayRef<real> constraint_distance_squared = shaked->constraint_distance_squared;
477 L1 = 1.0_real - lambda;
478 const int* ia = iatom;
479 for (ll = 0; (ll < ncon); ll++, ia += 3)
487 pbc_dx(pbc, x[i], x[j], rij[ll]);
491 rvec_sub(x[i], x[j], rij[ll]);
493 const real mm = 2.0_real * (invmass[i] + invmass[j]);
494 half_of_reduced_mass[ll] = 1.0_real / mm;
497 constraint_distance = L1 * ip[type].constr.dA + lambda * ip[type].constr.dB;
501 constraint_distance = ip[type].constr.dA;
503 constraint_distance_squared[ll] = gmx::square(constraint_distance);
504 distance_squared_tolerance[ll] = 0.5 / (constraint_distance_squared[ll] * tol);
509 case ConstraintVariable::Positions:
514 constraint_distance_squared,
518 half_of_reduced_mass,
521 distance_squared_tolerance,
522 scaled_lagrange_multiplier,
525 case ConstraintVariable::Velocities:
530 constraint_distance_squared,
533 half_of_reduced_mass,
536 distance_squared_tolerance,
537 scaled_lagrange_multiplier,
541 default: gmx_incons("Unknown constraint quantity for SHAKE");
548 fprintf(fplog, "Shake did not converge in %d steps\n", maxnit);
550 fprintf(stderr, "Shake did not converge in %d steps\n", maxnit);
558 "Inner product between old and new vector <= 0.0!\n"
559 "constraint #%d atoms %d and %d\n",
561 iatom[3 * (error - 1) + 1] + 1,
562 iatom[3 * (error - 1) + 2] + 1);
565 "Inner product between old and new vector <= 0.0!\n"
566 "constraint #%d atoms %d and %d\n",
568 iatom[3 * (error - 1) + 1] + 1,
569 iatom[3 * (error - 1) + 2] + 1);
573 /* Constraint virial and correct the Lagrange multipliers for the length */
577 for (ll = 0; (ll < ncon); ll++, ia += 3)
583 if ((econq == ConstraintVariable::Positions) && !v.empty())
585 /* Correct the velocities */
586 real mm = scaled_lagrange_multiplier[ll] * invmass[i] * invdt;
587 for (d = 0; d < DIM; d++)
589 v[ia[1]][d] += mm * rij[ll][d];
591 mm = scaled_lagrange_multiplier[ll] * invmass[j] * invdt;
592 for (d = 0; d < DIM; d++)
594 v[ia[2]][d] -= mm * rij[ll][d];
599 /* constraint virial */
602 const real mm = scaled_lagrange_multiplier[ll];
603 for (d = 0; d < DIM; d++)
605 const real tmp = mm * rij[ll][d];
606 for (d2 = 0; d2 < DIM; d2++)
608 vir_r_m_dr[d][d2] -= tmp * rij[ll][d2];
614 /* cshake and crattle produce Lagrange multipliers scaled by
615 the reciprocal of the constraint length, so fix that */
618 constraint_distance = L1 * ip[type].constr.dA + lambda * ip[type].constr.dB;
622 constraint_distance = ip[type].constr.dA;
624 scaled_lagrange_multiplier[ll] *= constraint_distance;
630 //! Check that constraints are satisfied.
631 static void check_cons(FILE* log,
633 ArrayRef<const RVec> x,
634 ArrayRef<const RVec> prime,
635 ArrayRef<const RVec> v,
637 ArrayRef<const t_iparams> ip,
639 const real invmass[],
640 ConstraintVariable econq)
647 GMX_ASSERT(!v.empty(), "Input has to be non-null");
648 fprintf(log, " i mi j mj before after should be\n");
649 const int* ia = iatom;
650 for (i = 0; (i < nc); i++, ia += 3)
654 rvec_sub(x[ai], x[aj], dx);
659 case ConstraintVariable::Positions:
662 pbc_dx(pbc, prime[ai], prime[aj], dx);
666 rvec_sub(prime[ai], prime[aj], dx);
670 "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n",
677 ip[ia[0]].constr.dA);
679 case ConstraintVariable::Velocities:
680 rvec_sub(v[ai], v[aj], dv);
682 rvec_sub(prime[ai], prime[aj], dv);
685 "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n",
694 default: gmx_incons("Unknown constraint quantity for SHAKE");
700 static bool bshakef(FILE* log,
702 const real invmass[],
703 const InteractionDefinitions& idef,
704 const t_inputrec& ir,
705 ArrayRef<const RVec> x_s,
706 ArrayRef<RVec> prime,
716 ConstraintVariable econq)
719 int i, n0, ncon, blen, type, ll;
720 int tnit = 0, trij = 0;
722 ncon = idef.il[F_CONSTR].size() / 3;
724 for (ll = 0; ll < ncon; ll++)
726 shaked->scaled_lagrange_multiplier[ll] = 0;
729 // TODO Rewrite this block so that it is obvious that i, iatoms
730 // and lam are all iteration variables. Is this easier if the
731 // sblock data structure is organized differently?
732 const int* iatoms = &(idef.il[F_CONSTR].iatoms[shaked->sblock[0]]);
733 ArrayRef<real> lam = shaked->scaled_lagrange_multiplier;
734 for (i = 0; (i < shaked->numShakeBlocks());)
736 blen = (shaked->sblock[i + 1] - shaked->sblock[i]);
749 ir.efep != FreeEnergyPerturbationType::No,
760 if (bDumpOnError && log)
763 check_cons(log, blen, x_s, prime, v, pbc, idef.iparams, iatoms, invmass, econq);
770 iatoms += 3 * blen; /* Increment pointer! */
771 lam = lam.subArray(blen, lam.ssize() - blen);
774 /* only for position part? */
775 if (econq == ConstraintVariable::Positions)
777 if (ir.efep != FreeEnergyPerturbationType::No)
779 ArrayRef<const t_iparams> iparams = idef.iparams;
781 /* TODO This should probably use invdt, so that sd integrator scaling works properly */
782 dt_2 = 1 / gmx::square(ir.delta_t);
784 for (ll = 0; ll < ncon; ll++)
786 type = idef.il[F_CONSTR].iatoms[3 * ll];
788 /* Per equations in the manual, dv/dl = -2 \sum_ll lagrangian_ll * r_ll * (d_B - d_A) */
789 /* The vector scaled_lagrange_multiplier[ll] contains the value -2 r_ll eta_ll
790 (eta_ll is the estimate of the Langrangian, definition on page 336 of Ryckaert et
791 al 1977), so the pre-factors are already present. */
792 const real bondA = iparams[type].constr.dA;
793 const real bondB = iparams[type].constr.dB;
794 dvdl += shaked->scaled_lagrange_multiplier[ll] * dt_2 * (bondB - bondA);
801 if (tnit > shaked->gamma)
803 shaked->delta *= -0.5;
805 shaked->omega += shaked->delta;
806 shaked->gamma = tnit;
808 inc_nrnb(nrnb, eNR_SHAKE, tnit);
809 inc_nrnb(nrnb, eNR_SHAKE_RIJ, trij);
812 inc_nrnb(nrnb, eNR_CONSTR_V, trij * 2);
816 inc_nrnb(nrnb, eNR_CONSTR_VIR, trij);
822 bool constrain_shake(FILE* log,
824 const real invmass[],
825 const InteractionDefinitions& idef,
826 const t_inputrec& ir,
827 ArrayRef<const RVec> x_s,
828 ArrayRef<RVec> xprime,
829 ArrayRef<RVec> vprime,
839 ConstraintVariable econq)
841 if (shaked->numShakeBlocks() == 0)
848 case (ConstraintVariable::Positions):
850 log, shaked, invmass, idef, ir, x_s, xprime, pbc, nrnb, lambda, dvdlambda, invdt, v, bCalcVir, vir_r_m_dr, bDumpOnError, econq);
852 case (ConstraintVariable::Velocities):
873 "Internal error, SHAKE called for constraining something else than "