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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
54 #include "gromacs/domdec/domdec_struct.h"
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/mdtypes/mdatom.h"
63 #include "gromacs/topology/invblock.h"
64 #include "gromacs/utility/fatalerror.h"
65 #include "gromacs/utility/smalloc.h"
73 real* half_of_reduced_mass;
74 real* distance_squared_tolerance;
75 real* constraint_distance_squared;
81 int nblocks; /* The number of SHAKE blocks */
82 int* sblock; /* The SHAKE blocks */
83 int sblock_nalloc; /* The allocation size of sblock */
84 /*! \brief Scaled Lagrange multiplier for each constraint.
86 * Value is -2 * eta from p. 336 of the paper, divided by the
87 * constraint distance. */
88 real* scaled_lagrange_multiplier;
89 int lagr_nalloc; /* The allocation size of scaled_lagrange_multiplier */
92 shakedata* shake_init()
100 d->half_of_reduced_mass = nullptr;
101 d->distance_squared_tolerance = nullptr;
102 d->constraint_distance_squared = nullptr;
104 /* SOR initialization */
112 void done_shake(shakedata* d)
115 sfree(d->half_of_reduced_mass);
116 sfree(d->distance_squared_tolerance);
117 sfree(d->constraint_distance_squared);
119 sfree(d->scaled_lagrange_multiplier);
129 //! Compares sort blocks.
130 static int pcomp(const void* p1, const void* p2)
133 int min1, min2, max1, max2;
134 const t_sortblock* a1 = reinterpret_cast<const t_sortblock*>(p1);
135 const t_sortblock* a2 = reinterpret_cast<const t_sortblock*>(p2);
137 db = a1->blocknr - a2->blocknr;
144 min1 = std::min(a1->iatom[1], a1->iatom[2]);
145 max1 = std::max(a1->iatom[1], a1->iatom[2]);
146 min2 = std::min(a2->iatom[1], a2->iatom[2]);
147 max2 = std::max(a2->iatom[1], a2->iatom[2]);
159 //! Prints sortblocks
160 static void pr_sortblock(FILE* fp, const char* title, int nsb, t_sortblock sb[])
164 fprintf(fp, "%s\n", title);
165 for (i = 0; (i < nsb); i++)
167 fprintf(fp, "i: %5d, iatom: (%5d %5d %5d), blocknr: %5d\n", i, sb[i].iatom[0],
168 sb[i].iatom[1], sb[i].iatom[2], sb[i].blocknr);
172 //! Reallocates a vector.
173 static void resizeLagrangianData(shakedata* shaked, int ncons)
175 if (ncons > shaked->lagr_nalloc)
177 shaked->lagr_nalloc = over_alloc_dd(ncons);
178 srenew(shaked->scaled_lagrange_multiplier, shaked->lagr_nalloc);
182 void make_shake_sblock_serial(shakedata* shaked, InteractionDefinitions* idef, const t_mdatoms& md)
190 /* Since we are processing the local topology,
191 * the F_CONSTRNC ilist has been concatenated to the F_CONSTR ilist.
193 ncons = idef->il[F_CONSTR].size() / 3;
195 init_blocka(&sblocks);
196 sfree(sblocks.index); // To solve memory leak
197 gen_sblocks(nullptr, 0, md.homenr, *idef, &sblocks, FALSE);
200 bstart=(idef->nodeid > 0) ? blocks->multinr[idef->nodeid-1] : 0;
201 nblocks=blocks->multinr[idef->nodeid] - bstart;
204 shaked->nblocks = sblocks.nr;
207 fprintf(debug, "ncons: %d, bstart: %d, nblocks: %d\n", ncons, bstart, shaked->nblocks);
210 /* Calculate block number for each atom */
211 inv_sblock = make_invblocka(&sblocks, md.nr);
213 done_blocka(&sblocks);
215 /* Store the block number in temp array and
216 * sort the constraints in order of the sblock number
217 * and the atom numbers, really sorting a segment of the array!
219 int* iatom = idef->il[F_CONSTR].iatoms.data();
221 for (i = 0; (i < ncons); i++, iatom += 3)
223 for (m = 0; (m < 3); m++)
225 sb[i].iatom[m] = iatom[m];
227 sb[i].blocknr = inv_sblock[iatom[1]];
230 /* Now sort the blocks */
233 pr_sortblock(debug, "Before sorting", ncons, sb);
234 fprintf(debug, "Going to sort constraints\n");
237 std::qsort(sb, ncons, sizeof(*sb), pcomp);
241 pr_sortblock(debug, "After sorting", ncons, sb);
244 iatom = idef->il[F_CONSTR].iatoms.data();
245 for (i = 0; (i < ncons); i++, iatom += 3)
247 for (m = 0; (m < 3); m++)
249 iatom[m] = sb[i].iatom[m];
254 snew(shaked->sblock, shaked->nblocks + 1);
256 for (i = 0; (i < ncons); i++)
258 if (sb[i].blocknr != bnr)
261 shaked->sblock[j++] = 3 * i;
265 shaked->sblock[j++] = 3 * ncons;
267 if (j != (shaked->nblocks + 1))
269 fprintf(stderr, "bstart: %d\n", bstart);
270 fprintf(stderr, "j: %d, nblocks: %d, ncons: %d\n", j, shaked->nblocks, ncons);
271 for (i = 0; (i < ncons); i++)
273 fprintf(stderr, "i: %5d sb[i].blocknr: %5d\n", i, sb[i].blocknr);
275 for (j = 0; (j <= shaked->nblocks); j++)
277 fprintf(stderr, "sblock[%3d]=%5d\n", j, shaked->sblock[j]);
281 "sblocks does not match idef->il[F_CONSTR]");
285 resizeLagrangianData(shaked, ncons);
288 // TODO: Check if this code is useful. It might never be called.
289 void make_shake_sblock_dd(shakedata* shaked, const InteractionList& ilcon, const gmx_domdec_t* dd)
293 if (dd->ncg_home + 1 > shaked->sblock_nalloc)
295 shaked->sblock_nalloc = over_alloc_dd(dd->ncg_home + 1);
296 srenew(shaked->sblock, shaked->sblock_nalloc);
299 ncons = ilcon.size() / 3;
300 const int* iatom = ilcon.iatoms.data();
303 for (c = 0; c < ncons; c++)
305 if (c == 0 || iatom[1] >= cg + 1)
307 shaked->sblock[shaked->nblocks++] = 3 * c;
308 while (iatom[1] >= cg + 1)
315 shaked->sblock[shaked->nblocks] = 3 * ncons;
316 resizeLagrangianData(shaked, ncons);
319 /*! \brief Inner kernel for SHAKE constraints
321 * Original implementation from R.C. van Schaik and W.F. van Gunsteren
322 * (ETH Zuerich, June 1992), adapted for GROMACS by David van der
323 * Spoel November 1992.
325 * The algorithm here is based section five of Ryckaert, Ciccotti and
326 * Berendsen, J Comp Phys, 23, 327, 1977.
328 * \param[in] iatom Mini-topology of triples of constraint type (unused in this
329 * function) and indices of the two atoms involved
330 * \param[in] ncon Number of constraints
331 * \param[out] nnit Number of iterations performed
332 * \param[in] maxnit Maximum number of iterations permitted
333 * \param[in] constraint_distance_squared The objective value for each constraint
334 * \param[inout] positions The initial (and final) values of the positions of all atoms
335 * \param[in] initial_displacements The initial displacements of each constraint
336 * \param[in] half_of_reduced_mass Half of the reduced mass for each constraint
337 * \param[in] omega SHAKE over-relaxation factor (set non-1.0 by
338 * using shake-sor=yes in the .mdp, but there is no documentation anywhere)
339 * \param[in] invmass Inverse mass of each atom
340 * \param[in] distance_squared_tolerance Multiplicative tolerance on the difference in the
341 * square of the constrained distance (see code)
342 * \param[out] scaled_lagrange_multiplier Scaled Lagrange multiplier for each constraint (-2 * eta from p. 336
343 * of the paper, divided by the constraint distance)
344 * \param[out] nerror Zero upon success, returns one more than the index of the
345 * problematic constraint if the input was malformed
347 * \todo Make SHAKE use better data structures, in particular for iatom. */
348 void cshake(const int iatom[],
352 const real constraint_distance_squared[],
354 const real initial_displacements[],
355 const real half_of_reduced_mass[],
357 const real invmass[],
358 const real distance_squared_tolerance[],
359 real scaled_lagrange_multiplier[],
362 /* default should be increased! MRS 8/4/2009 */
363 const real mytol = 1e-10;
365 int ll, i, j, i3, j3, l3;
366 int ix, iy, iz, jx, jy, jz;
368 real constraint_distance_squared_ll;
369 real r_prime_squared;
370 real scaled_lagrange_multiplier_ll;
371 real r_prime_x, r_prime_y, r_prime_z, diff, im, jm;
372 real xh, yh, zh, rijx, rijy, rijz;
373 int nit, error, nconv;
376 // TODO nconv is used solely as a boolean, so we should write the
380 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
383 for (ll = 0; (ll < ncon) && (error == 0); ll++)
386 rijx = initial_displacements[l3 + XX];
387 rijy = initial_displacements[l3 + YY];
388 rijz = initial_displacements[l3 + ZZ];
400 /* Compute r prime between atoms i and j, which is the
401 displacement *before* this update stage */
402 r_prime_x = positions[ix] - positions[jx];
403 r_prime_y = positions[iy] - positions[jy];
404 r_prime_z = positions[iz] - positions[jz];
405 r_prime_squared = (r_prime_x * r_prime_x + r_prime_y * r_prime_y + r_prime_z * r_prime_z);
406 constraint_distance_squared_ll = constraint_distance_squared[ll];
407 diff = constraint_distance_squared_ll - r_prime_squared;
409 /* iconvf is less than 1 when the error is smaller than a bound */
410 iconvf = fabs(diff) * distance_squared_tolerance[ll];
414 nconv = static_cast<int>(iconvf);
415 r_dot_r_prime = (rijx * r_prime_x + rijy * r_prime_y + rijz * r_prime_z);
417 if (r_dot_r_prime < constraint_distance_squared_ll * mytol)
423 /* The next line solves equation 5.6 (neglecting
424 the term in g^2), for g */
425 scaled_lagrange_multiplier_ll = omega * diff * half_of_reduced_mass[ll] / r_dot_r_prime;
426 scaled_lagrange_multiplier[ll] += scaled_lagrange_multiplier_ll;
427 xh = rijx * scaled_lagrange_multiplier_ll;
428 yh = rijy * scaled_lagrange_multiplier_ll;
429 zh = rijz * scaled_lagrange_multiplier_ll;
432 positions[ix] += xh * im;
433 positions[iy] += yh * im;
434 positions[iz] += zh * im;
435 positions[jx] -= xh * jm;
436 positions[jy] -= yh * jm;
437 positions[jz] -= zh * jm;
446 //! Implements RATTLE (ie. SHAKE for velocity verlet integrators)
447 static void crattle(const int iatom[],
451 const real constraint_distance_squared[],
456 const real invmass[],
457 const real distance_squared_tolerance[],
458 real scaled_lagrange_multiplier[],
463 * r.c. van schaik and w.f. van gunsteren
466 * Adapted for use with Gromacs by David van der Spoel november 92 and later.
467 * rattle added by M.R. Shirts, April 2004, from code written by Jay Ponder in TINKER
468 * second part of rattle algorithm
471 int ll, i, j, i3, j3, l3;
472 int ix, iy, iz, jx, jy, jz;
473 real constraint_distance_squared_ll;
474 real vpijd, vx, vy, vz, acor, fac, im, jm;
475 real xh, yh, zh, rijx, rijy, rijz;
476 int nit, error, nconv;
479 // TODO nconv is used solely as a boolean, so we should write the
483 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
486 for (ll = 0; (ll < ncon) && (error == 0); ll++)
502 vx = vp[ix] - vp[jx];
503 vy = vp[iy] - vp[jy];
504 vz = vp[iz] - vp[jz];
506 vpijd = vx * rijx + vy * rijy + vz * rijz;
507 constraint_distance_squared_ll = constraint_distance_squared[ll];
509 /* iconv is zero when the error is smaller than a bound */
510 iconvf = fabs(vpijd) * (distance_squared_tolerance[ll] / invdt);
514 nconv = static_cast<int>(iconvf);
515 fac = omega * 2.0 * m2[ll] / constraint_distance_squared_ll;
517 scaled_lagrange_multiplier[ll] += acor;
539 static int vec_shakef(FILE* fplog,
541 const real invmass[],
543 ArrayRef<const t_iparams> ip,
551 real scaled_lagrange_multiplier[],
556 ConstraintVariable econq)
559 real *half_of_reduced_mass, *distance_squared_tolerance, *constraint_distance_squared;
561 int nit = 0, ll, i, j, d, d2, type;
565 real constraint_distance;
567 if (ncon > shaked->nalloc)
569 shaked->nalloc = over_alloc_dd(ncon);
570 srenew(shaked->rij, shaked->nalloc);
571 srenew(shaked->half_of_reduced_mass, shaked->nalloc);
572 srenew(shaked->distance_squared_tolerance, shaked->nalloc);
573 srenew(shaked->constraint_distance_squared, shaked->nalloc);
576 half_of_reduced_mass = shaked->half_of_reduced_mass;
577 distance_squared_tolerance = shaked->distance_squared_tolerance;
578 constraint_distance_squared = shaked->constraint_distance_squared;
581 const int* ia = iatom;
582 for (ll = 0; (ll < ncon); ll++, ia += 3)
588 mm = 2.0 * (invmass[i] + invmass[j]);
589 rij[ll][XX] = x[i][XX] - x[j][XX];
590 rij[ll][YY] = x[i][YY] - x[j][YY];
591 rij[ll][ZZ] = x[i][ZZ] - x[j][ZZ];
592 half_of_reduced_mass[ll] = 1.0 / mm;
595 constraint_distance = L1 * ip[type].constr.dA + lambda * ip[type].constr.dB;
599 constraint_distance = ip[type].constr.dA;
601 constraint_distance_squared[ll] = gmx::square(constraint_distance);
602 distance_squared_tolerance[ll] = 0.5 / (constraint_distance_squared[ll] * tol);
607 case ConstraintVariable::Positions:
608 cshake(iatom, ncon, &nit, maxnit, constraint_distance_squared, prime[0], rij[0],
609 half_of_reduced_mass, omega, invmass, distance_squared_tolerance,
610 scaled_lagrange_multiplier, &error);
612 case ConstraintVariable::Velocities:
613 crattle(iatom, ncon, &nit, maxnit, constraint_distance_squared, prime[0], rij[0],
614 half_of_reduced_mass, omega, invmass, distance_squared_tolerance,
615 scaled_lagrange_multiplier, &error, invdt);
617 default: gmx_incons("Unknown constraint quantity for SHAKE");
624 fprintf(fplog, "Shake did not converge in %d steps\n", maxnit);
626 fprintf(stderr, "Shake did not converge in %d steps\n", maxnit);
634 "Inner product between old and new vector <= 0.0!\n"
635 "constraint #%d atoms %d and %d\n",
636 error - 1, iatom[3 * (error - 1) + 1] + 1, iatom[3 * (error - 1) + 2] + 1);
639 "Inner product between old and new vector <= 0.0!\n"
640 "constraint #%d atoms %d and %d\n",
641 error - 1, iatom[3 * (error - 1) + 1] + 1, iatom[3 * (error - 1) + 2] + 1);
645 /* Constraint virial and correct the Lagrange multipliers for the length */
649 for (ll = 0; (ll < ncon); ll++, ia += 3)
655 if ((econq == ConstraintVariable::Positions) && v != nullptr)
657 /* Correct the velocities */
658 mm = scaled_lagrange_multiplier[ll] * invmass[i] * invdt;
659 for (d = 0; d < DIM; d++)
661 v[ia[1]][d] += mm * rij[ll][d];
663 mm = scaled_lagrange_multiplier[ll] * invmass[j] * invdt;
664 for (d = 0; d < DIM; d++)
666 v[ia[2]][d] -= mm * rij[ll][d];
671 /* constraint virial */
674 mm = scaled_lagrange_multiplier[ll];
675 for (d = 0; d < DIM; d++)
677 tmp = mm * rij[ll][d];
678 for (d2 = 0; d2 < DIM; d2++)
680 vir_r_m_dr[d][d2] -= tmp * rij[ll][d2];
686 /* cshake and crattle produce Lagrange multipliers scaled by
687 the reciprocal of the constraint length, so fix that */
690 constraint_distance = L1 * ip[type].constr.dA + lambda * ip[type].constr.dB;
694 constraint_distance = ip[type].constr.dA;
696 scaled_lagrange_multiplier[ll] *= constraint_distance;
702 //! Check that constraints are satisfied.
703 static void check_cons(FILE* log,
708 ArrayRef<const t_iparams> ip,
710 const real invmass[],
711 ConstraintVariable econq)
718 GMX_ASSERT(v, "Input has to be non-null");
719 fprintf(log, " i mi j mj before after should be\n");
720 const int* ia = iatom;
721 for (i = 0; (i < nc); i++, ia += 3)
725 rvec_sub(x[ai], x[aj], dx);
730 case ConstraintVariable::Positions:
731 rvec_sub(prime[ai], prime[aj], dx);
733 fprintf(log, "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n", ai + 1,
734 1.0 / invmass[ai], aj + 1, 1.0 / invmass[aj], d, dp, ip[ia[0]].constr.dA);
736 case ConstraintVariable::Velocities:
737 rvec_sub(v[ai], v[aj], dv);
739 rvec_sub(prime[ai], prime[aj], dv);
741 fprintf(log, "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n", ai + 1,
742 1.0 / invmass[ai], aj + 1, 1.0 / invmass[aj], d, dp, 0.);
744 default: gmx_incons("Unknown constraint quantity for SHAKE");
750 static bool bshakef(FILE* log,
752 const real invmass[],
753 const InteractionDefinitions& idef,
754 const t_inputrec& ir,
765 ConstraintVariable econq)
767 real *lam, dt_2, dvdl;
768 int i, n0, ncon, blen, type, ll;
769 int tnit = 0, trij = 0;
771 ncon = idef.il[F_CONSTR].size() / 3;
773 for (ll = 0; ll < ncon; ll++)
775 shaked->scaled_lagrange_multiplier[ll] = 0;
778 // TODO Rewrite this block so that it is obvious that i, iatoms
779 // and lam are all iteration variables. Is this easier if the
780 // sblock data structure is organized differently?
781 const int* iatoms = &(idef.il[F_CONSTR].iatoms[shaked->sblock[0]]);
782 lam = shaked->scaled_lagrange_multiplier;
783 for (i = 0; (i < shaked->nblocks);)
785 blen = (shaked->sblock[i + 1] - shaked->sblock[i]);
787 n0 = vec_shakef(log, shaked, invmass, blen, idef.iparams, iatoms, ir.shake_tol, x_s, prime,
788 shaked->omega, ir.efep != efepNO, lambda, lam, invdt, v, bCalcVir,
793 if (bDumpOnError && log)
796 check_cons(log, blen, x_s, prime, v, idef.iparams, iatoms, invmass, econq);
803 iatoms += 3 * blen; /* Increment pointer! */
807 /* only for position part? */
808 if (econq == ConstraintVariable::Positions)
810 if (ir.efep != efepNO)
812 ArrayRef<const t_iparams> iparams = idef.iparams;
814 /* TODO This should probably use invdt, so that sd integrator scaling works properly */
815 dt_2 = 1 / gmx::square(ir.delta_t);
817 for (ll = 0; ll < ncon; ll++)
819 type = idef.il[F_CONSTR].iatoms[3 * ll];
821 /* Per equations in the manual, dv/dl = -2 \sum_ll lagrangian_ll * r_ll * (d_B - d_A) */
822 /* The vector scaled_lagrange_multiplier[ll] contains the value -2 r_ll eta_ll
823 (eta_ll is the estimate of the Langrangian, definition on page 336 of Ryckaert et
824 al 1977), so the pre-factors are already present. */
825 const real bondA = iparams[type].constr.dA;
826 const real bondB = iparams[type].constr.dB;
827 dvdl += shaked->scaled_lagrange_multiplier[ll] * dt_2 * (bondB - bondA);
834 if (tnit > shaked->gamma)
836 shaked->delta *= -0.5;
838 shaked->omega += shaked->delta;
839 shaked->gamma = tnit;
841 inc_nrnb(nrnb, eNR_SHAKE, tnit);
842 inc_nrnb(nrnb, eNR_SHAKE_RIJ, trij);
845 inc_nrnb(nrnb, eNR_CONSTR_V, trij * 2);
849 inc_nrnb(nrnb, eNR_CONSTR_VIR, trij);
855 bool constrain_shake(FILE* log,
857 const real invmass[],
858 const InteractionDefinitions& idef,
859 const t_inputrec& ir,
871 ConstraintVariable econq)
873 if (shaked->nblocks == 0)
880 case (ConstraintVariable::Positions):
881 bOK = bshakef(log, shaked, invmass, idef, ir, x_s, xprime, nrnb, lambda, dvdlambda,
882 invdt, v, bCalcVir, vir_r_m_dr, bDumpOnError, econq);
884 case (ConstraintVariable::Velocities):
885 bOK = bshakef(log, shaked, invmass, idef, ir, x_s, vprime, nrnb, lambda, dvdlambda,
886 invdt, nullptr, bCalcVir, vir_r_m_dr, bDumpOnError, econq);
890 "Internal error, SHAKE called for constraining something else than "