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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 */
116 //! Compares sort blocks.
117 static int pcomp(const void *p1, const void *p2)
120 int min1, min2, max1, max2;
121 const t_sortblock *a1 = reinterpret_cast<const t_sortblock*>(p1);
122 const t_sortblock *a2 = reinterpret_cast<const t_sortblock*>(p2);
124 db = a1->blocknr-a2->blocknr;
131 min1 = std::min(a1->iatom[1], a1->iatom[2]);
132 max1 = std::max(a1->iatom[1], a1->iatom[2]);
133 min2 = std::min(a2->iatom[1], a2->iatom[2]);
134 max2 = std::max(a2->iatom[1], a2->iatom[2]);
146 //! Prints sortblocks
147 static void pr_sortblock(FILE *fp, const char *title, int nsb, t_sortblock sb[])
151 fprintf(fp, "%s\n", title);
152 for (i = 0; (i < nsb); i++)
154 fprintf(fp, "i: %5d, iatom: (%5d %5d %5d), blocknr: %5d\n",
155 i, sb[i].iatom[0], sb[i].iatom[1], sb[i].iatom[2],
160 //! Reallocates a vector.
161 static void resizeLagrangianData(shakedata *shaked, int ncons)
163 if (ncons > shaked->lagr_nalloc)
165 shaked->lagr_nalloc = over_alloc_dd(ncons);
166 srenew(shaked->scaled_lagrange_multiplier, shaked->lagr_nalloc);
171 make_shake_sblock_serial(shakedata *shaked,
172 const t_idef *idef, const t_mdatoms &md)
181 /* Since we are processing the local topology,
182 * the F_CONSTRNC ilist has been concatenated to the F_CONSTR ilist.
184 ncons = idef->il[F_CONSTR].nr/3;
186 init_blocka(&sblocks);
187 gen_sblocks(nullptr, 0, md.homenr, idef, &sblocks, FALSE);
190 bstart=(idef->nodeid > 0) ? blocks->multinr[idef->nodeid-1] : 0;
191 nblocks=blocks->multinr[idef->nodeid] - bstart;
194 shaked->nblocks = sblocks.nr;
197 fprintf(debug, "ncons: %d, bstart: %d, nblocks: %d\n",
198 ncons, bstart, shaked->nblocks);
201 /* Calculate block number for each atom */
202 inv_sblock = make_invblocka(&sblocks, md.nr);
204 done_blocka(&sblocks);
206 /* Store the block number in temp array and
207 * sort the constraints in order of the sblock number
208 * and the atom numbers, really sorting a segment of the array!
210 iatom = idef->il[F_CONSTR].iatoms;
212 for (i = 0; (i < ncons); i++, iatom += 3)
214 for (m = 0; (m < 3); m++)
216 sb[i].iatom[m] = iatom[m];
218 sb[i].blocknr = inv_sblock[iatom[1]];
221 /* Now sort the blocks */
224 pr_sortblock(debug, "Before sorting", ncons, sb);
225 fprintf(debug, "Going to sort constraints\n");
228 qsort(sb, ncons, sizeof(*sb), pcomp);
232 pr_sortblock(debug, "After sorting", ncons, sb);
235 iatom = idef->il[F_CONSTR].iatoms;
236 for (i = 0; (i < ncons); i++, iatom += 3)
238 for (m = 0; (m < 3); m++)
240 iatom[m] = sb[i].iatom[m];
245 snew(shaked->sblock, shaked->nblocks+1);
247 for (i = 0; (i < ncons); i++)
249 if (sb[i].blocknr != bnr)
252 shaked->sblock[j++] = 3*i;
256 shaked->sblock[j++] = 3*ncons;
258 if (j != (shaked->nblocks+1))
260 fprintf(stderr, "bstart: %d\n", bstart);
261 fprintf(stderr, "j: %d, nblocks: %d, ncons: %d\n",
262 j, shaked->nblocks, ncons);
263 for (i = 0; (i < ncons); i++)
265 fprintf(stderr, "i: %5d sb[i].blocknr: %5d\n", i, sb[i].blocknr);
267 for (j = 0; (j <= shaked->nblocks); j++)
269 fprintf(stderr, "sblock[%3d]=%5d\n", j, shaked->sblock[j]);
271 gmx_fatal(FARGS, "DEATH HORROR: "
272 "sblocks does not match idef->il[F_CONSTR]");
276 resizeLagrangianData(shaked, ncons);
280 make_shake_sblock_dd(shakedata *shaked,
281 const t_ilist *ilcon, const t_block *cgs,
282 const gmx_domdec_t *dd)
287 if (dd->ncg_home+1 > shaked->sblock_nalloc)
289 shaked->sblock_nalloc = over_alloc_dd(dd->ncg_home+1);
290 srenew(shaked->sblock, shaked->sblock_nalloc);
294 iatom = ilcon->iatoms;
297 for (c = 0; c < ncons; c++)
299 if (c == 0 || iatom[1] >= cgs->index[cg+1])
301 shaked->sblock[shaked->nblocks++] = 3*c;
302 while (iatom[1] >= cgs->index[cg+1])
309 shaked->sblock[shaked->nblocks] = 3*ncons;
310 resizeLagrangianData(shaked, ncons);
313 /*! \brief Inner kernel for SHAKE constraints
315 * Original implementation from R.C. van Schaik and W.F. van Gunsteren
316 * (ETH Zuerich, June 1992), adapted for GROMACS by David van der
317 * Spoel November 1992.
319 * The algorithm here is based section five of Ryckaert, Ciccotti and
320 * Berendsen, J Comp Phys, 23, 327, 1977.
322 * \param[in] iatom Mini-topology of triples of constraint type (unused in this
323 * function) and indices of the two atoms involved
324 * \param[in] ncon Number of constraints
325 * \param[out] nnit Number of iterations performed
326 * \param[in] maxnit Maximum number of iterations permitted
327 * \param[in] constraint_distance_squared The objective value for each constraint
328 * \param[inout] positions The initial (and final) values of the positions of all atoms
329 * \param[in] initial_displacements The initial displacements of each constraint
330 * \param[in] half_of_reduced_mass Half of the reduced mass for each constraint
331 * \param[in] omega SHAKE over-relaxation factor (set non-1.0 by
332 * using shake-sor=yes in the .mdp, but there is no documentation anywhere)
333 * \param[in] invmass Inverse mass of each atom
334 * \param[in] distance_squared_tolerance Multiplicative tolerance on the difference in the
335 * square of the constrained distance (see code)
336 * \param[out] scaled_lagrange_multiplier Scaled Lagrange multiplier for each constraint (-2 * eta from p. 336
337 * of the paper, divided by the constraint distance)
338 * \param[out] nerror Zero upon success, returns one more than the index of the
339 * problematic constraint if the input was malformed
341 * \todo Make SHAKE use better data structures, in particular for iatom. */
342 void cshake(const int iatom[], int ncon, int *nnit, int maxnit,
343 const real constraint_distance_squared[], real positions[],
344 const real initial_displacements[], const real half_of_reduced_mass[], real omega,
345 const real invmass[], const real distance_squared_tolerance[],
346 real scaled_lagrange_multiplier[], int *nerror)
348 /* default should be increased! MRS 8/4/2009 */
349 const real mytol = 1e-10;
351 int ll, i, j, i3, j3, l3;
352 int ix, iy, iz, jx, jy, jz;
354 real constraint_distance_squared_ll;
355 real r_prime_squared;
356 real scaled_lagrange_multiplier_ll;
357 real r_prime_x, r_prime_y, r_prime_z, diff, im, jm;
358 real xh, yh, zh, rijx, rijy, rijz;
359 int nit, error, nconv;
362 // TODO nconv is used solely as a boolean, so we should write the
366 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
369 for (ll = 0; (ll < ncon) && (error == 0); ll++)
372 rijx = initial_displacements[l3+XX];
373 rijy = initial_displacements[l3+YY];
374 rijz = initial_displacements[l3+ZZ];
386 /* Compute r prime between atoms i and j, which is the
387 displacement *before* this update stage */
388 r_prime_x = positions[ix]-positions[jx];
389 r_prime_y = positions[iy]-positions[jy];
390 r_prime_z = positions[iz]-positions[jz];
391 r_prime_squared = (r_prime_x * r_prime_x +
392 r_prime_y * r_prime_y +
393 r_prime_z * r_prime_z);
394 constraint_distance_squared_ll = constraint_distance_squared[ll];
395 diff = constraint_distance_squared_ll - r_prime_squared;
397 /* iconvf is less than 1 when the error is smaller than a bound */
398 iconvf = fabs(diff) * distance_squared_tolerance[ll];
402 nconv = static_cast<int>(iconvf);
403 r_dot_r_prime = (rijx * r_prime_x +
407 if (r_dot_r_prime < constraint_distance_squared_ll * mytol)
413 /* The next line solves equation 5.6 (neglecting
414 the term in g^2), for g */
415 scaled_lagrange_multiplier_ll = omega*diff*half_of_reduced_mass[ll]/r_dot_r_prime;
416 scaled_lagrange_multiplier[ll] += scaled_lagrange_multiplier_ll;
417 xh = rijx * scaled_lagrange_multiplier_ll;
418 yh = rijy * scaled_lagrange_multiplier_ll;
419 zh = rijz * scaled_lagrange_multiplier_ll;
422 positions[ix] += xh*im;
423 positions[iy] += yh*im;
424 positions[iz] += zh*im;
425 positions[jx] -= xh*jm;
426 positions[jy] -= yh*jm;
427 positions[jz] -= zh*jm;
436 //! Implements RATTLE (ie. SHAKE for velocity verlet integrators)
438 crattle(const int iatom[], int ncon, int *nnit, int maxnit,
439 const real constraint_distance_squared[], real vp[], const real rij[], const real m2[], real omega,
440 const real invmass[], const real distance_squared_tolerance[], real scaled_lagrange_multiplier[],
441 int *nerror, real invdt)
444 * r.c. van schaik and w.f. van gunsteren
447 * Adapted for use with Gromacs by David van der Spoel november 92 and later.
448 * rattle added by M.R. Shirts, April 2004, from code written by Jay Ponder in TINKER
449 * second part of rattle algorithm
452 int ll, i, j, i3, j3, l3;
453 int ix, iy, iz, jx, jy, jz;
454 real constraint_distance_squared_ll;
455 real vpijd, vx, vy, vz, acor, fac, im, jm;
456 real xh, yh, zh, rijx, rijy, rijz;
457 int nit, error, nconv;
460 // TODO nconv is used solely as a boolean, so we should write the
464 for (nit = 0; (nit < maxnit) && (nconv != 0) && (error == 0); nit++)
467 for (ll = 0; (ll < ncon) && (error == 0); ll++)
487 vpijd = vx*rijx+vy*rijy+vz*rijz;
488 constraint_distance_squared_ll = constraint_distance_squared[ll];
490 /* iconv is zero when the error is smaller than a bound */
491 iconvf = fabs(vpijd)*(distance_squared_tolerance[ll]/invdt);
495 nconv = static_cast<int>(iconvf);
496 fac = omega*2.0*m2[ll]/constraint_distance_squared_ll;
498 scaled_lagrange_multiplier[ll] += acor;
520 static int vec_shakef(FILE *fplog, shakedata *shaked,
521 const real invmass[], int ncon,
522 t_iparams ip[], t_iatom *iatom,
523 real tol, const rvec x[], rvec prime[], real omega,
524 bool bFEP, real lambda, real scaled_lagrange_multiplier[],
526 bool bCalcVir, tensor vir_r_m_dr, ConstraintVariable econq)
529 real *half_of_reduced_mass, *distance_squared_tolerance, *constraint_distance_squared;
531 int nit = 0, ll, i, j, d, d2, type;
536 real constraint_distance;
538 if (ncon > shaked->nalloc)
540 shaked->nalloc = over_alloc_dd(ncon);
541 srenew(shaked->rij, shaked->nalloc);
542 srenew(shaked->half_of_reduced_mass, shaked->nalloc);
543 srenew(shaked->distance_squared_tolerance, shaked->nalloc);
544 srenew(shaked->constraint_distance_squared, shaked->nalloc);
547 half_of_reduced_mass = shaked->half_of_reduced_mass;
548 distance_squared_tolerance = shaked->distance_squared_tolerance;
549 constraint_distance_squared = shaked->constraint_distance_squared;
553 for (ll = 0; (ll < ncon); ll++, ia += 3)
559 mm = 2.0*(invmass[i]+invmass[j]);
560 rij[ll][XX] = x[i][XX]-x[j][XX];
561 rij[ll][YY] = x[i][YY]-x[j][YY];
562 rij[ll][ZZ] = x[i][ZZ]-x[j][ZZ];
563 half_of_reduced_mass[ll] = 1.0/mm;
566 constraint_distance = L1*ip[type].constr.dA + lambda*ip[type].constr.dB;
570 constraint_distance = ip[type].constr.dA;
572 constraint_distance_squared[ll] = gmx::square(constraint_distance);
573 distance_squared_tolerance[ll] = 0.5/(constraint_distance_squared[ll]*tol);
578 case ConstraintVariable::Positions:
579 cshake(iatom, ncon, &nit, maxnit, constraint_distance_squared, prime[0], rij[0], half_of_reduced_mass, omega, invmass, distance_squared_tolerance, scaled_lagrange_multiplier, &error);
581 case ConstraintVariable::Velocities:
582 crattle(iatom, ncon, &nit, maxnit, constraint_distance_squared, prime[0], rij[0], half_of_reduced_mass, omega, invmass, distance_squared_tolerance, scaled_lagrange_multiplier, &error, invdt);
585 gmx_incons("Unknown constraint quantity for SHAKE");
592 fprintf(fplog, "Shake did not converge in %d steps\n", maxnit);
594 fprintf(stderr, "Shake did not converge in %d steps\n", maxnit);
601 fprintf(fplog, "Inner product between old and new vector <= 0.0!\n"
602 "constraint #%d atoms %d and %d\n",
603 error-1, iatom[3*(error-1)+1]+1, iatom[3*(error-1)+2]+1);
605 fprintf(stderr, "Inner product between old and new vector <= 0.0!\n"
606 "constraint #%d atoms %d and %d\n",
607 error-1, iatom[3*(error-1)+1]+1, iatom[3*(error-1)+2]+1);
611 /* Constraint virial and correct the Lagrange multipliers for the length */
615 for (ll = 0; (ll < ncon); ll++, ia += 3)
621 if ((econq == ConstraintVariable::Positions) && v != nullptr)
623 /* Correct the velocities */
624 mm = scaled_lagrange_multiplier[ll]*invmass[i]*invdt;
625 for (d = 0; d < DIM; d++)
627 v[ia[1]][d] += mm*rij[ll][d];
629 mm = scaled_lagrange_multiplier[ll]*invmass[j]*invdt;
630 for (d = 0; d < DIM; d++)
632 v[ia[2]][d] -= mm*rij[ll][d];
637 /* constraint virial */
640 mm = scaled_lagrange_multiplier[ll];
641 for (d = 0; d < DIM; d++)
644 for (d2 = 0; d2 < DIM; d2++)
646 vir_r_m_dr[d][d2] -= tmp*rij[ll][d2];
652 /* cshake and crattle produce Lagrange multipliers scaled by
653 the reciprocal of the constraint length, so fix that */
656 constraint_distance = L1*ip[type].constr.dA + lambda*ip[type].constr.dB;
660 constraint_distance = ip[type].constr.dA;
662 scaled_lagrange_multiplier[ll] *= constraint_distance;
668 //! Check that constraints are satisfied.
669 static void check_cons(FILE *log, int nc, const rvec x[], rvec prime[], rvec v[],
670 t_iparams ip[], t_iatom *iatom,
671 const real invmass[], ConstraintVariable econq)
679 GMX_ASSERT(v, "Input has to be non-null");
681 " i mi j mj before after should be\n");
683 for (i = 0; (i < nc); i++, ia += 3)
687 rvec_sub(x[ai], x[aj], dx);
692 case ConstraintVariable::Positions:
693 rvec_sub(prime[ai], prime[aj], dx);
695 fprintf(log, "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n",
696 ai+1, 1.0/invmass[ai],
697 aj+1, 1.0/invmass[aj], d, dp, ip[ia[0]].constr.dA);
699 case ConstraintVariable::Velocities:
700 rvec_sub(v[ai], v[aj], dv);
702 rvec_sub(prime[ai], prime[aj], dv);
704 fprintf(log, "%5d %5.2f %5d %5.2f %10.5f %10.5f %10.5f\n",
705 ai+1, 1.0/invmass[ai],
706 aj+1, 1.0/invmass[aj], d, dp, 0.);
709 gmx_incons("Unknown constraint quantity for SHAKE");
716 bshakef(FILE *log, shakedata *shaked,
717 const real invmass[],
718 const t_idef &idef, const t_inputrec &ir, const rvec x_s[], rvec prime[],
719 t_nrnb *nrnb, real lambda, real *dvdlambda,
720 real invdt, rvec *v, bool bCalcVir, tensor vir_r_m_dr,
721 bool bDumpOnError, ConstraintVariable econq)
724 real *lam, dt_2, dvdl;
725 int i, n0, ncon, blen, type, ll;
726 int tnit = 0, trij = 0;
728 ncon = idef.il[F_CONSTR].nr/3;
730 for (ll = 0; ll < ncon; ll++)
732 shaked->scaled_lagrange_multiplier[ll] = 0;
735 // TODO Rewrite this block so that it is obvious that i, iatoms
736 // and lam are all iteration variables. Is this easier if the
737 // sblock data structure is organized differently?
738 iatoms = &(idef.il[F_CONSTR].iatoms[shaked->sblock[0]]);
739 lam = shaked->scaled_lagrange_multiplier;
740 for (i = 0; (i < shaked->nblocks); )
742 blen = (shaked->sblock[i+1]-shaked->sblock[i]);
744 n0 = vec_shakef(log, shaked, invmass, blen, idef.iparams,
745 iatoms, ir.shake_tol, x_s, prime, shaked->omega,
746 ir.efep != efepNO, lambda, lam, invdt, v, bCalcVir, vir_r_m_dr,
751 if (bDumpOnError && log)
754 check_cons(log, blen, x_s, prime, v, idef.iparams, iatoms, invmass, econq);
761 iatoms += 3*blen; /* Increment pointer! */
765 /* only for position part? */
766 if (econq == ConstraintVariable::Positions)
768 if (ir.efep != efepNO)
771 /* TODO This should probably use invdt, so that sd integrator scaling works properly */
772 dt_2 = 1/gmx::square(ir.delta_t);
774 for (ll = 0; ll < ncon; ll++)
776 type = idef.il[F_CONSTR].iatoms[3*ll];
778 /* Per equations in the manual, dv/dl = -2 \sum_ll lagrangian_ll * r_ll * (d_B - d_A) */
779 /* The vector scaled_lagrange_multiplier[ll] contains the value -2 r_ll eta_ll (eta_ll is the
780 estimate of the Langrangian, definition on page 336 of Ryckaert et al 1977),
781 so the pre-factors are already present. */
782 bondA = idef.iparams[type].constr.dA;
783 bondB = idef.iparams[type].constr.dB;
784 dvdl += shaked->scaled_lagrange_multiplier[ll] * dt_2 * (bondB - bondA);
791 if (tnit > shaked->gamma)
793 shaked->delta *= -0.5;
795 shaked->omega += shaked->delta;
796 shaked->gamma = tnit;
798 inc_nrnb(nrnb, eNR_SHAKE, tnit);
799 inc_nrnb(nrnb, eNR_SHAKE_RIJ, trij);
802 inc_nrnb(nrnb, eNR_CONSTR_V, trij*2);
806 inc_nrnb(nrnb, eNR_CONSTR_VIR, trij);
813 constrain_shake(FILE *log,
815 const real invmass[],
817 const t_inputrec &ir,
829 ConstraintVariable econq)
831 if (shaked->nblocks == 0)
838 case (ConstraintVariable::Positions):
839 bOK = bshakef(log, shaked,
841 idef, ir, x_s, xprime, nrnb,
843 invdt, v, bCalcVir, vir_r_m_dr,
844 bDumpOnError, econq);
846 case (ConstraintVariable::Velocities):
847 bOK = bshakef(log, shaked,
849 idef, ir, x_s, vprime, nrnb,
851 invdt, nullptr, bCalcVir, vir_r_m_dr,
852 bDumpOnError, econq);
855 gmx_fatal(FARGS, "Internal error, SHAKE called for constraining something else than coordinates");