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38 * \brief Defines SHAKE code.
40 * \author David van der Spoel <david.vanderspoel@icm.uu.se>
41 * \author Berk Hess <hess@kth.se>
42 * \author Mark Abraham <mark.j.abraham@gmail.com>
43 * \ingroup module_mdlib
53 #include "gromacs/domdec/domdec_struct.h"
54 #include "gromacs/gmxlib/nrnb.h"
55 #include "gromacs/math/functions.h"
56 #include "gromacs/math/vec.h"
57 #include "gromacs/mdlib/constr.h"
58 #include "gromacs/mdlib/splitter.h"
59 #include "gromacs/mdtypes/inputrec.h"
60 #include "gromacs/mdtypes/md_enums.h"
61 #include "gromacs/mdtypes/mdatom.h"
62 #include "gromacs/topology/invblock.h"
63 #include "gromacs/utility/fatalerror.h"
64 #include "gromacs/utility/smalloc.h"
72 real* half_of_reduced_mass;
73 real* distance_squared_tolerance;
74 real* constraint_distance_squared;
80 int nblocks; /* The number of SHAKE blocks */
81 int* sblock; /* The SHAKE blocks */
82 int sblock_nalloc; /* The allocation size of sblock */
83 /*! \brief Scaled Lagrange multiplier for each constraint.
85 * Value is -2 * eta from p. 336 of the paper, divided by the
86 * constraint distance. */
87 real* scaled_lagrange_multiplier;
88 int lagr_nalloc; /* The allocation size of scaled_lagrange_multiplier */
91 shakedata* shake_init()
99 d->half_of_reduced_mass = nullptr;
100 d->distance_squared_tolerance = nullptr;
101 d->constraint_distance_squared = nullptr;
103 /* SOR initialization */
111 void done_shake(shakedata* d)
114 sfree(d->half_of_reduced_mass);
115 sfree(d->distance_squared_tolerance);
116 sfree(d->constraint_distance_squared);
118 sfree(d->scaled_lagrange_multiplier);
128 //! Compares sort blocks.
129 static int pcomp(const void* p1, const void* p2)
132 int min1, min2, max1, max2;
133 const t_sortblock* a1 = reinterpret_cast<const t_sortblock*>(p1);
134 const t_sortblock* a2 = reinterpret_cast<const t_sortblock*>(p2);
136 db = a1->blocknr - a2->blocknr;
143 min1 = std::min(a1->iatom[1], a1->iatom[2]);
144 max1 = std::max(a1->iatom[1], a1->iatom[2]);
145 min2 = std::min(a2->iatom[1], a2->iatom[2]);
146 max2 = std::max(a2->iatom[1], a2->iatom[2]);
158 //! Prints sortblocks
159 static void pr_sortblock(FILE* fp, const char* title, int nsb, t_sortblock sb[])
163 fprintf(fp, "%s\n", title);
164 for (i = 0; (i < nsb); i++)
166 fprintf(fp, "i: %5d, iatom: (%5d %5d %5d), blocknr: %5d\n", i, sb[i].iatom[0],
167 sb[i].iatom[1], sb[i].iatom[2], sb[i].blocknr);
171 //! Reallocates a vector.
172 static void resizeLagrangianData(shakedata* shaked, int ncons)
174 if (ncons > shaked->lagr_nalloc)
176 shaked->lagr_nalloc = over_alloc_dd(ncons);
177 srenew(shaked->scaled_lagrange_multiplier, shaked->lagr_nalloc);
181 void make_shake_sblock_serial(shakedata* shaked, const t_idef* 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].nr / 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 iatom = idef->il[F_CONSTR].iatoms;
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;
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 t_ilist* ilcon, const gmx_domdec_t* dd)
294 if (dd->ncg_home + 1 > shaked->sblock_nalloc)
296 shaked->sblock_nalloc = over_alloc_dd(dd->ncg_home + 1);
297 srenew(shaked->sblock, shaked->sblock_nalloc);
300 ncons = ilcon->nr / 3;
301 iatom = ilcon->iatoms;
304 for (c = 0; c < ncons; c++)
306 if (c == 0 || iatom[1] >= cg + 1)
308 shaked->sblock[shaked->nblocks++] = 3 * c;
309 while (iatom[1] >= cg + 1)
316 shaked->sblock[shaked->nblocks] = 3 * ncons;
317 resizeLagrangianData(shaked, ncons);
320 /*! \brief Inner kernel for SHAKE constraints
322 * Original implementation from R.C. van Schaik and W.F. van Gunsteren
323 * (ETH Zuerich, June 1992), adapted for GROMACS by David van der
324 * Spoel November 1992.
326 * The algorithm here is based section five of Ryckaert, Ciccotti and
327 * Berendsen, J Comp Phys, 23, 327, 1977.
329 * \param[in] iatom Mini-topology of triples of constraint type (unused in this
330 * function) and indices of the two atoms involved
331 * \param[in] ncon Number of constraints
332 * \param[out] nnit Number of iterations performed
333 * \param[in] maxnit Maximum number of iterations permitted
334 * \param[in] constraint_distance_squared The objective value for each constraint
335 * \param[inout] positions The initial (and final) values of the positions of all atoms
336 * \param[in] initial_displacements The initial displacements of each constraint
337 * \param[in] half_of_reduced_mass Half of the reduced mass for each constraint
338 * \param[in] omega SHAKE over-relaxation factor (set non-1.0 by
339 * using shake-sor=yes in the .mdp, but there is no documentation anywhere)
340 * \param[in] invmass Inverse mass of each atom
341 * \param[in] distance_squared_tolerance Multiplicative tolerance on the difference in the
342 * square of the constrained distance (see code)
343 * \param[out] scaled_lagrange_multiplier Scaled Lagrange multiplier for each constraint (-2 * eta from p. 336
344 * of the paper, divided by the constraint distance)
345 * \param[out] nerror Zero upon success, returns one more than the index of the
346 * problematic constraint if the input was malformed
348 * \todo Make SHAKE use better data structures, in particular for iatom. */
349 void cshake(const int iatom[],
353 const real constraint_distance_squared[],
355 const real initial_displacements[],
356 const real half_of_reduced_mass[],
358 const real invmass[],
359 const real distance_squared_tolerance[],
360 real scaled_lagrange_multiplier[],
363 /* default should be increased! MRS 8/4/2009 */
364 const real mytol = 1e-10;
366 int ll, i, j, i3, j3, l3;
367 int ix, iy, iz, jx, jy, jz;
369 real constraint_distance_squared_ll;
370 real r_prime_squared;
371 real scaled_lagrange_multiplier_ll;
372 real r_prime_x, r_prime_y, r_prime_z, diff, im, jm;
373 real xh, yh, zh, rijx, rijy, rijz;
374 int nit, error, nconv;
377 // TODO nconv is used solely as a boolean, so we should write the
381 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
384 for (ll = 0; (ll < ncon) && (error == 0); ll++)
387 rijx = initial_displacements[l3 + XX];
388 rijy = initial_displacements[l3 + YY];
389 rijz = initial_displacements[l3 + ZZ];
401 /* Compute r prime between atoms i and j, which is the
402 displacement *before* this update stage */
403 r_prime_x = positions[ix] - positions[jx];
404 r_prime_y = positions[iy] - positions[jy];
405 r_prime_z = positions[iz] - positions[jz];
406 r_prime_squared = (r_prime_x * r_prime_x + r_prime_y * r_prime_y + r_prime_z * r_prime_z);
407 constraint_distance_squared_ll = constraint_distance_squared[ll];
408 diff = constraint_distance_squared_ll - r_prime_squared;
410 /* iconvf is less than 1 when the error is smaller than a bound */
411 iconvf = fabs(diff) * distance_squared_tolerance[ll];
415 nconv = static_cast<int>(iconvf);
416 r_dot_r_prime = (rijx * r_prime_x + rijy * r_prime_y + rijz * r_prime_z);
418 if (r_dot_r_prime < constraint_distance_squared_ll * mytol)
424 /* The next line solves equation 5.6 (neglecting
425 the term in g^2), for g */
426 scaled_lagrange_multiplier_ll = omega * diff * half_of_reduced_mass[ll] / r_dot_r_prime;
427 scaled_lagrange_multiplier[ll] += scaled_lagrange_multiplier_ll;
428 xh = rijx * scaled_lagrange_multiplier_ll;
429 yh = rijy * scaled_lagrange_multiplier_ll;
430 zh = rijz * scaled_lagrange_multiplier_ll;
433 positions[ix] += xh * im;
434 positions[iy] += yh * im;
435 positions[iz] += zh * im;
436 positions[jx] -= xh * jm;
437 positions[jy] -= yh * jm;
438 positions[jz] -= zh * jm;
447 //! Implements RATTLE (ie. SHAKE for velocity verlet integrators)
448 static void crattle(const int iatom[],
452 const real constraint_distance_squared[],
457 const real invmass[],
458 const real distance_squared_tolerance[],
459 real scaled_lagrange_multiplier[],
464 * r.c. van schaik and w.f. van gunsteren
467 * Adapted for use with Gromacs by David van der Spoel november 92 and later.
468 * rattle added by M.R. Shirts, April 2004, from code written by Jay Ponder in TINKER
469 * second part of rattle algorithm
472 int ll, i, j, i3, j3, l3;
473 int ix, iy, iz, jx, jy, jz;
474 real constraint_distance_squared_ll;
475 real vpijd, vx, vy, vz, acor, fac, im, jm;
476 real xh, yh, zh, rijx, rijy, rijz;
477 int nit, error, nconv;
480 // TODO nconv is used solely as a boolean, so we should write the
484 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
487 for (ll = 0; (ll < ncon) && (error == 0); ll++)
503 vx = vp[ix] - vp[jx];
504 vy = vp[iy] - vp[jy];
505 vz = vp[iz] - vp[jz];
507 vpijd = vx * rijx + vy * rijy + vz * rijz;
508 constraint_distance_squared_ll = constraint_distance_squared[ll];
510 /* iconv is zero when the error is smaller than a bound */
511 iconvf = fabs(vpijd) * (distance_squared_tolerance[ll] / invdt);
515 nconv = static_cast<int>(iconvf);
516 fac = omega * 2.0 * m2[ll] / constraint_distance_squared_ll;
518 scaled_lagrange_multiplier[ll] += acor;
540 static int vec_shakef(FILE* fplog,
542 const real invmass[],
552 real scaled_lagrange_multiplier[],
557 ConstraintVariable econq)
560 real * half_of_reduced_mass, *distance_squared_tolerance, *constraint_distance_squared;
562 int nit = 0, ll, i, j, d, d2, type;
567 real constraint_distance;
569 if (ncon > shaked->nalloc)
571 shaked->nalloc = over_alloc_dd(ncon);
572 srenew(shaked->rij, shaked->nalloc);
573 srenew(shaked->half_of_reduced_mass, shaked->nalloc);
574 srenew(shaked->distance_squared_tolerance, shaked->nalloc);
575 srenew(shaked->constraint_distance_squared, shaked->nalloc);
578 half_of_reduced_mass = shaked->half_of_reduced_mass;
579 distance_squared_tolerance = shaked->distance_squared_tolerance;
580 constraint_distance_squared = shaked->constraint_distance_squared;
584 for (ll = 0; (ll < ncon); ll++, ia += 3)
590 mm = 2.0 * (invmass[i] + invmass[j]);
591 rij[ll][XX] = x[i][XX] - x[j][XX];
592 rij[ll][YY] = x[i][YY] - x[j][YY];
593 rij[ll][ZZ] = x[i][ZZ] - x[j][ZZ];
594 half_of_reduced_mass[ll] = 1.0 / mm;
597 constraint_distance = L1 * ip[type].constr.dA + lambda * ip[type].constr.dB;
601 constraint_distance = ip[type].constr.dA;
603 constraint_distance_squared[ll] = gmx::square(constraint_distance);
604 distance_squared_tolerance[ll] = 0.5 / (constraint_distance_squared[ll] * tol);
609 case ConstraintVariable::Positions:
610 cshake(iatom, ncon, &nit, maxnit, constraint_distance_squared, prime[0], rij[0],
611 half_of_reduced_mass, omega, invmass, distance_squared_tolerance,
612 scaled_lagrange_multiplier, &error);
614 case ConstraintVariable::Velocities:
615 crattle(iatom, ncon, &nit, maxnit, constraint_distance_squared, prime[0], rij[0],
616 half_of_reduced_mass, omega, invmass, distance_squared_tolerance,
617 scaled_lagrange_multiplier, &error, invdt);
619 default: gmx_incons("Unknown constraint quantity for SHAKE");
626 fprintf(fplog, "Shake did not converge in %d steps\n", maxnit);
628 fprintf(stderr, "Shake did not converge in %d steps\n", maxnit);
636 "Inner product between old and new vector <= 0.0!\n"
637 "constraint #%d atoms %d and %d\n",
638 error - 1, iatom[3 * (error - 1) + 1] + 1, iatom[3 * (error - 1) + 2] + 1);
641 "Inner product between old and new vector <= 0.0!\n"
642 "constraint #%d atoms %d and %d\n",
643 error - 1, iatom[3 * (error - 1) + 1] + 1, iatom[3 * (error - 1) + 2] + 1);
647 /* Constraint virial and correct the Lagrange multipliers for the length */
651 for (ll = 0; (ll < ncon); ll++, ia += 3)
657 if ((econq == ConstraintVariable::Positions) && v != nullptr)
659 /* Correct the velocities */
660 mm = scaled_lagrange_multiplier[ll] * invmass[i] * invdt;
661 for (d = 0; d < DIM; d++)
663 v[ia[1]][d] += mm * rij[ll][d];
665 mm = scaled_lagrange_multiplier[ll] * invmass[j] * invdt;
666 for (d = 0; d < DIM; d++)
668 v[ia[2]][d] -= mm * rij[ll][d];
673 /* constraint virial */
676 mm = scaled_lagrange_multiplier[ll];
677 for (d = 0; d < DIM; d++)
679 tmp = mm * rij[ll][d];
680 for (d2 = 0; d2 < DIM; d2++)
682 vir_r_m_dr[d][d2] -= tmp * rij[ll][d2];
688 /* cshake and crattle produce Lagrange multipliers scaled by
689 the reciprocal of the constraint length, so fix that */
692 constraint_distance = L1 * ip[type].constr.dA + lambda * ip[type].constr.dB;
696 constraint_distance = ip[type].constr.dA;
698 scaled_lagrange_multiplier[ll] *= constraint_distance;
704 //! Check that constraints are satisfied.
705 static void check_cons(FILE* log,
712 const real invmass[],
713 ConstraintVariable econq)
721 GMX_ASSERT(v, "Input has to be non-null");
722 fprintf(log, " i mi j mj before after should be\n");
724 for (i = 0; (i < nc); i++, ia += 3)
728 rvec_sub(x[ai], x[aj], dx);
733 case ConstraintVariable::Positions:
734 rvec_sub(prime[ai], prime[aj], dx);
736 fprintf(log, "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n", ai + 1,
737 1.0 / invmass[ai], aj + 1, 1.0 / invmass[aj], d, dp, ip[ia[0]].constr.dA);
739 case ConstraintVariable::Velocities:
740 rvec_sub(v[ai], v[aj], dv);
742 rvec_sub(prime[ai], prime[aj], dv);
744 fprintf(log, "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n", ai + 1,
745 1.0 / invmass[ai], aj + 1, 1.0 / invmass[aj], d, dp, 0.);
747 default: gmx_incons("Unknown constraint quantity for SHAKE");
753 static bool bshakef(FILE* log,
755 const real invmass[],
757 const t_inputrec& ir,
768 ConstraintVariable econq)
771 real * lam, dt_2, dvdl;
772 int i, n0, ncon, blen, type, ll;
773 int tnit = 0, trij = 0;
775 ncon = idef.il[F_CONSTR].nr / 3;
777 for (ll = 0; ll < ncon; ll++)
779 shaked->scaled_lagrange_multiplier[ll] = 0;
782 // TODO Rewrite this block so that it is obvious that i, iatoms
783 // and lam are all iteration variables. Is this easier if the
784 // sblock data structure is organized differently?
785 iatoms = &(idef.il[F_CONSTR].iatoms[shaked->sblock[0]]);
786 lam = shaked->scaled_lagrange_multiplier;
787 for (i = 0; (i < shaked->nblocks);)
789 blen = (shaked->sblock[i + 1] - shaked->sblock[i]);
791 n0 = vec_shakef(log, shaked, invmass, blen, idef.iparams, iatoms, ir.shake_tol, x_s, prime,
792 shaked->omega, ir.efep != efepNO, lambda, lam, invdt, v, bCalcVir,
797 if (bDumpOnError && log)
800 check_cons(log, blen, x_s, prime, v, idef.iparams, iatoms, invmass, econq);
807 iatoms += 3 * blen; /* Increment pointer! */
811 /* only for position part? */
812 if (econq == ConstraintVariable::Positions)
814 if (ir.efep != efepNO)
817 /* TODO This should probably use invdt, so that sd integrator scaling works properly */
818 dt_2 = 1 / gmx::square(ir.delta_t);
820 for (ll = 0; ll < ncon; ll++)
822 type = idef.il[F_CONSTR].iatoms[3 * ll];
824 /* Per equations in the manual, dv/dl = -2 \sum_ll lagrangian_ll * r_ll * (d_B - d_A) */
825 /* The vector scaled_lagrange_multiplier[ll] contains the value -2 r_ll eta_ll
826 (eta_ll is the estimate of the Langrangian, definition on page 336 of Ryckaert et
827 al 1977), so the pre-factors are already present. */
828 bondA = idef.iparams[type].constr.dA;
829 bondB = idef.iparams[type].constr.dB;
830 dvdl += shaked->scaled_lagrange_multiplier[ll] * dt_2 * (bondB - bondA);
837 if (tnit > shaked->gamma)
839 shaked->delta *= -0.5;
841 shaked->omega += shaked->delta;
842 shaked->gamma = tnit;
844 inc_nrnb(nrnb, eNR_SHAKE, tnit);
845 inc_nrnb(nrnb, eNR_SHAKE_RIJ, trij);
848 inc_nrnb(nrnb, eNR_CONSTR_V, trij * 2);
852 inc_nrnb(nrnb, eNR_CONSTR_VIR, trij);
858 bool constrain_shake(FILE* log,
860 const real invmass[],
862 const t_inputrec& ir,
874 ConstraintVariable econq)
876 if (shaked->nblocks == 0)
883 case (ConstraintVariable::Positions):
884 bOK = bshakef(log, shaked, invmass, idef, ir, x_s, xprime, nrnb, lambda, dvdlambda,
885 invdt, v, bCalcVir, vir_r_m_dr, bDumpOnError, econq);
887 case (ConstraintVariable::Velocities):
888 bOK = bshakef(log, shaked, invmass, idef, ir, x_s, vprime, nrnb, lambda, dvdlambda,
889 invdt, nullptr, bCalcVir, vir_r_m_dr, bDumpOnError, econq);
893 "Internal error, SHAKE called for constraining something else than "