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42 #include "gromacs/commandline/pargs.h"
43 #include "gromacs/fileio/confio.h"
44 #include "gromacs/fileio/tpxio.h"
45 #include "gromacs/fileio/trxio.h"
46 #include "gromacs/fileio/xvgr.h"
47 #include "gromacs/gmxana/gmx_ana.h"
48 #include "gromacs/gmxana/gstat.h"
49 #include "gromacs/legacyheaders/macros.h"
50 #include "gromacs/legacyheaders/typedefs.h"
51 #include "gromacs/legacyheaders/viewit.h"
52 #include "gromacs/math/utilities.h"
53 #include "gromacs/math/vec.h"
54 #include "gromacs/pbcutil/rmpbc.h"
55 #include "gromacs/statistics/statistics.h"
56 #include "gromacs/topology/index.h"
57 #include "gromacs/utility/fatalerror.h"
58 #include "gromacs/utility/futil.h"
59 #include "gromacs/utility/smalloc.h"
61 #define FACTOR 1000.0 /* Convert nm^2/ps to 10e-5 cm^2/s */
62 /* NORMAL = total diffusion coefficient (default). X,Y,Z is diffusion
63 coefficient in X,Y,Z direction. LATERAL is diffusion coefficient in
64 plane perpendicular to axis
67 NOT_USED, NORMAL, X, Y, Z, LATERAL
71 real t0; /* start time and time increment between */
72 real delta_t; /* time between restart points */
73 real beginfit, /* the begin/end time for fits as reals between */
75 real dim_factor; /* the dimensionality factor for the diffusion
77 real **data; /* the displacement data. First index is the group
78 number, second is frame number */
79 real *time; /* frame time */
80 real *mass; /* masses for mass-weighted msd */
82 rvec **x0; /* original positions */
83 rvec *com; /* center of mass correction for each frame */
84 gmx_stats_t **lsq; /* fitting stats for individual molecule msds */
85 msd_type type; /* the type of msd to calculate (lateral, etc.)*/
86 int axis; /* the axis along which to calculate */
88 int nrestart; /* number of restart points */
89 int nmol; /* number of molecules (for bMol) */
90 int nframes; /* number of frames */
92 int ngrp; /* number of groups to use for msd calculation */
94 int **ndata; /* the number of msds (particles/mols) per data
98 typedef real t_calc_func (t_corr *curr, int nx, atom_id index[], int nx0, rvec xc[],
99 rvec dcom, gmx_bool bTen, matrix mat);
101 static real thistime(t_corr *curr)
103 return curr->time[curr->nframes];
106 static gmx_bool in_data(t_corr *curr, int nx00)
108 return curr->nframes-curr->n_offs[nx00];
111 t_corr *init_corr(int nrgrp, int type, int axis, real dim_factor,
112 int nmol, gmx_bool bTen, gmx_bool bMass, real dt, t_topology *top,
113 real beginfit, real endfit)
120 curr->type = (msd_type)type;
125 curr->beginfit = (1 - 2*GMX_REAL_EPS)*beginfit;
126 curr->endfit = (1 + 2*GMX_REAL_EPS)*endfit;
131 curr->dim_factor = dim_factor;
133 snew(curr->ndata, nrgrp);
134 snew(curr->data, nrgrp);
137 snew(curr->datam, nrgrp);
139 for (i = 0; (i < nrgrp); i++)
141 curr->ndata[i] = NULL;
142 curr->data[i] = NULL;
145 curr->datam[i] = NULL;
153 snew(curr->mass, curr->nmol);
154 for (i = 0; i < curr->nmol; i++)
164 snew(curr->mass, atoms->nr);
165 for (i = 0; (i < atoms->nr); i++)
167 curr->mass[i] = atoms->atom[i].m;
175 static void corr_print(t_corr *curr, gmx_bool bTen, const char *fn, const char *title,
177 real msdtime, real beginfit, real endfit,
178 real *DD, real *SigmaD, char *grpname[],
179 const output_env_t oenv)
184 out = xvgropen(fn, title, output_env_get_xvgr_tlabel(oenv), yaxis, oenv);
187 fprintf(out, "# MSD gathered over %g %s with %d restarts\n",
188 msdtime, output_env_get_time_unit(oenv), curr->nrestart);
189 fprintf(out, "# Diffusion constants fitted from time %g to %g %s\n",
190 beginfit, endfit, output_env_get_time_unit(oenv));
191 for (i = 0; i < curr->ngrp; i++)
193 fprintf(out, "# D[%10s] = %.4f (+/- %.4f) (1e-5 cm^2/s)\n",
194 grpname[i], DD[i], SigmaD[i]);
197 for (i = 0; i < curr->nframes; i++)
199 fprintf(out, "%10g", output_env_conv_time(oenv, curr->time[i]));
200 for (j = 0; j < curr->ngrp; j++)
202 fprintf(out, " %10g", curr->data[j][i]);
205 fprintf(out, " %10g %10g %10g %10g %10g %10g",
206 curr->datam[j][i][XX][XX],
207 curr->datam[j][i][YY][YY],
208 curr->datam[j][i][ZZ][ZZ],
209 curr->datam[j][i][YY][XX],
210 curr->datam[j][i][ZZ][XX],
211 curr->datam[j][i][ZZ][YY]);
219 /* called from corr_loop, to do the main calculations */
220 static void calc_corr(t_corr *curr, int nr, int nx, atom_id index[], rvec xc[],
221 gmx_bool bRmCOMM, rvec com, t_calc_func *calc1, gmx_bool bTen)
228 /* Check for new starting point */
229 if (curr->nlast < curr->nrestart)
231 if ((thistime(curr) >= (curr->nlast*curr->delta_t)) && (nr == 0))
233 memcpy(curr->x0[curr->nlast], xc, curr->ncoords*sizeof(xc[0]));
234 curr->n_offs[curr->nlast] = curr->nframes;
235 copy_rvec(com, curr->com[curr->nlast]);
240 /* nx0 appears to be the number of new starting points,
241 * so for all starting points, call calc1.
243 for (nx0 = 0; (nx0 < curr->nlast); nx0++)
247 rvec_sub(com, curr->com[nx0], dcom);
253 g = calc1(curr, nx, index, nx0, xc, dcom, bTen, mat);
255 printf("g[%d]=%g\n", nx0, g);
257 curr->data[nr][in_data(curr, nx0)] += g;
260 m_add(curr->datam[nr][in_data(curr, nx0)], mat,
261 curr->datam[nr][in_data(curr, nx0)]);
263 curr->ndata[nr][in_data(curr, nx0)]++;
267 /* the non-mass-weighted mean-squared displacement calcuation */
268 static real calc1_norm(t_corr *curr, int nx, atom_id index[], int nx0, rvec xc[],
269 rvec dcom, gmx_bool bTen, matrix mat)
278 for (i = 0; (i < nx); i++)
285 for (m = 0; (m < DIM); m++)
287 rv[m] = xc[ix][m] - curr->x0[nx0][ix][m] - dcom[m];
291 for (m2 = 0; m2 <= m; m2++)
293 mat[m][m2] += rv[m]*rv[m2];
301 r = xc[ix][curr->type-X] - curr->x0[nx0][ix][curr->type-X] -
306 for (m = 0; (m < DIM); m++)
310 r = xc[ix][m] - curr->x0[nx0][ix][m] - dcom[m];
316 gmx_fatal(FARGS, "Error: did not expect option value %d", curr->type);
321 msmul(mat, 1.0/nx, mat);
326 /* calculate the com of molecules in x and put it into xa */
327 static void calc_mol_com(int nmol, int *molindex, t_block *mols, t_atoms *atoms,
334 for (m = 0; m < nmol; m++)
339 for (i = mols->index[mol]; i < mols->index[mol+1]; i++)
341 mass = atoms->atom[i].m;
342 for (d = 0; d < DIM; d++)
344 xm[d] += mass*x[i][d];
348 svmul(1/mtot, xm, xa[m]);
352 static real calc_one_mw(t_corr *curr, int ix, int nx0, rvec xc[], real *tm,
353 rvec dcom, gmx_bool bTen, matrix mat)
369 for (m = 0; (m < DIM); m++)
371 rv[m] = xc[ix][m] - curr->x0[nx0][ix][m] - dcom[m];
372 r2 += mm*rv[m]*rv[m];
375 for (m2 = 0; m2 <= m; m2++)
377 mat[m][m2] += mm*rv[m]*rv[m2];
385 r = xc[ix][curr->type-X] - curr->x0[nx0][ix][curr->type-X] -
390 for (m = 0; (m < DIM); m++)
394 r = xc[ix][m] - curr->x0[nx0][ix][m] - dcom[m];
400 gmx_fatal(FARGS, "Options got screwed. Did not expect value %d\n", curr->type);
405 /* the normal, mass-weighted mean-squared displacement calcuation */
406 static real calc1_mw(t_corr *curr, int nx, atom_id index[], int nx0, rvec xc[],
407 rvec dcom, gmx_bool bTen, matrix mat)
414 for (i = 0; (i < nx); i++)
416 g += calc_one_mw(curr, index[i], nx0, xc, &tm, dcom, bTen, mat);
422 msmul(mat, 1/tm, mat);
428 /* prepare the coordinates by removing periodic boundary crossings.
429 gnx = the number of atoms/molecules
431 xcur = the current coordinates
432 xprev = the previous coordinates
433 box = the box matrix */
434 static void prep_data(gmx_bool bMol, int gnx, atom_id index[],
435 rvec xcur[], rvec xprev[], matrix box)
440 /* Remove periodicity */
441 for (m = 0; (m < DIM); m++)
443 hbox[m] = 0.5*box[m][m];
446 for (i = 0; (i < gnx); i++)
457 for (m = DIM-1; m >= 0; m--)
463 while (xcur[ind][m]-xprev[ind][m] <= -hbox[m])
465 rvec_inc(xcur[ind], box[m]);
467 while (xcur[ind][m]-xprev[ind][m] > hbox[m])
469 rvec_dec(xcur[ind], box[m]);
475 /* calculate the center of mass for a group
476 gnx = the number of atoms/molecules
478 xcur = the current coordinates
479 xprev = the previous coordinates
481 atoms = atom data (for mass)
482 com(output) = center of mass */
483 static void calc_com(gmx_bool bMol, int gnx, atom_id index[],
484 rvec xcur[], rvec xprev[], matrix box, t_atoms *atoms,
496 prep_data(bMol, gnx, index, xcur, xprev, box);
497 for (i = 0; (i < gnx); i++)
509 mass = atoms->atom[ind].m;
510 for (m = 0; m < DIM; m++)
512 sx[m] += mass*xcur[ind][m];
516 for (m = 0; m < DIM; m++)
518 com[m] = sx[m]/tmass;
523 static real calc1_mol(t_corr *curr, int nx, atom_id gmx_unused index[], int nx0, rvec xc[],
524 rvec dcom, gmx_bool bTen, matrix mat)
527 real g, tm, gtot, tt;
529 tt = curr->time[in_data(curr, nx0)];
533 for (i = 0; (i < nx); i++)
535 g = calc_one_mw(curr, i, nx0, xc, &tm, dcom, bTen, mat);
536 /* We don't need to normalize as the mass was set to 1 */
538 if (tt >= curr->beginfit && (curr->endfit < 0 || tt <= curr->endfit))
540 gmx_stats_add_point(curr->lsq[nx0][i], tt, g, 0, 0);
543 msmul(mat, 1.0/nx, mat);
548 void printmol(t_corr *curr, const char *fn,
549 const char *fn_pdb, int *molindex, t_topology *top,
550 rvec *x, int ePBC, matrix box, const output_env_t oenv)
556 real a, b, D, Dav, D2av, VarD, sqrtD, sqrtD_max, scale;
557 t_pdbinfo *pdbinfo = NULL;
560 out = xvgropen(fn, "Diffusion Coefficients / Molecule", "Molecule", "D", oenv);
564 if (top->atoms.pdbinfo == NULL)
566 snew(top->atoms.pdbinfo, top->atoms.nr);
568 pdbinfo = top->atoms.pdbinfo;
569 mol2a = top->mols.index;
574 for (i = 0; (i < curr->nmol); i++)
576 lsq1 = gmx_stats_init();
577 for (j = 0; (j < curr->nrestart); j++)
581 while (gmx_stats_get_point(curr->lsq[j][i], &xx, &yy, &dx, &dy, 0) == estatsOK)
583 gmx_stats_add_point(lsq1, xx, yy, dx, dy);
586 gmx_stats_get_ab(lsq1, elsqWEIGHT_NONE, &a, &b, NULL, NULL, NULL, NULL);
587 gmx_stats_done(lsq1);
589 D = a*FACTOR/curr->dim_factor;
596 fprintf(out, "%10d %10g\n", i, D);
600 if (sqrtD > sqrtD_max)
604 for (j = mol2a[molindex[i]]; j < mol2a[molindex[i]+1]; j++)
606 pdbinfo[j].bfac = sqrtD;
611 do_view(oenv, fn, "-graphtype bar");
613 /* Compute variance, stddev and error */
616 VarD = D2av - sqr(Dav);
617 printf("<D> = %.4f Std. Dev. = %.4f Error = %.4f\n",
618 Dav, sqrt(VarD), sqrt(VarD/curr->nmol));
623 while (scale*sqrtD_max > 10)
627 while (scale*sqrtD_max < 0.1)
631 for (i = 0; i < top->atoms.nr; i++)
633 pdbinfo[i].bfac *= scale;
635 write_sto_conf(fn_pdb, "molecular MSD", &top->atoms, x, NULL, ePBC, box);
639 /* this is the main loop for the correlation type functions
640 * fx and nx are file pointers to things like read_first_x and
643 int corr_loop(t_corr *curr, const char *fn, t_topology *top, int ePBC,
644 gmx_bool bMol, int gnx[], atom_id *index[],
645 t_calc_func *calc1, gmx_bool bTen, int *gnx_com, atom_id *index_com[],
646 real dt, real t_pdb, rvec **x_pdb, matrix box_pdb,
647 const output_env_t oenv)
649 rvec *x[2]; /* the coordinates to read */
650 rvec *xa[2]; /* the coordinates to calculate displacements for */
653 int natoms, i, j, cur = 0, maxframes = 0;
658 gmx_rmpbc_t gpbc = NULL;
660 natoms = read_first_x(oenv, &status, fn, &curr->t0, &(x[cur]), box);
662 fprintf(stderr, "Read %d atoms for first frame\n", natoms);
664 if ((gnx_com != NULL) && natoms < top->atoms.nr)
666 fprintf(stderr, "WARNING: The trajectory only contains part of the system (%d of %d atoms) and therefore the COM motion of only this part of the system will be removed\n", natoms, top->atoms.nr);
669 snew(x[prev], natoms);
673 curr->ncoords = curr->nmol;
674 snew(xa[0], curr->ncoords);
675 snew(xa[1], curr->ncoords);
679 curr->ncoords = natoms;
693 gpbc = gmx_rmpbc_init(&top->idef, ePBC, natoms);
696 /* the loop over all frames */
699 if (x_pdb && ((bFirst && t_pdb < t) ||
701 t_pdb > t - 0.5*(t - t_prev) &&
702 t_pdb < t + 0.5*(t - t_prev))))
706 snew(*x_pdb, natoms);
708 for (i = 0; i < natoms; i++)
710 copy_rvec(x[cur][i], (*x_pdb)[i]);
712 copy_mat(box, box_pdb);
716 /* check whether we've reached a restart point */
717 if (bRmod(t, curr->t0, dt))
721 srenew(curr->x0, curr->nrestart);
722 snew(curr->x0[curr->nrestart-1], curr->ncoords);
723 srenew(curr->com, curr->nrestart);
724 srenew(curr->n_offs, curr->nrestart);
725 srenew(curr->lsq, curr->nrestart);
726 snew(curr->lsq[curr->nrestart-1], curr->nmol);
727 for (i = 0; i < curr->nmol; i++)
729 curr->lsq[curr->nrestart-1][i] = gmx_stats_init();
734 fprintf(debug, "Extended data structures because of new restart %d\n",
738 /* create or extend the frame-based arrays */
739 if (curr->nframes >= maxframes-1)
743 for (i = 0; (i < curr->ngrp); i++)
745 curr->ndata[i] = NULL;
746 curr->data[i] = NULL;
749 curr->datam[i] = NULL;
755 for (i = 0; (i < curr->ngrp); i++)
757 srenew(curr->ndata[i], maxframes);
758 srenew(curr->data[i], maxframes);
761 srenew(curr->datam[i], maxframes);
763 for (j = maxframes-10; j < maxframes; j++)
765 curr->ndata[i][j] = 0;
766 curr->data[i][j] = 0;
769 clear_mat(curr->datam[i][j]);
773 srenew(curr->time, maxframes);
777 curr->time[curr->nframes] = t - curr->t0;
779 /* for the first frame, the previous frame is a copy of the first frame */
782 memcpy(xa[prev], xa[cur], curr->ncoords*sizeof(xa[prev][0]));
786 /* make the molecules whole */
789 gmx_rmpbc(gpbc, natoms, box, x[cur]);
792 /* calculate the molecules' centers of masses and put them into xa */
795 calc_mol_com(gnx[0], index[0], &top->mols, &top->atoms, x[cur], xa[cur]);
798 /* first remove the periodic boundary condition crossings */
799 for (i = 0; i < curr->ngrp; i++)
801 prep_data(bMol, gnx[i], index[i], xa[cur], xa[prev], box);
804 /* calculate the center of mass */
807 prep_data(bMol, gnx_com[0], index_com[0], xa[cur], xa[prev], box);
808 calc_com(bMol, gnx_com[0], index_com[0], xa[cur], xa[prev], box,
812 /* loop over all groups in index file */
813 for (i = 0; (i < curr->ngrp); i++)
815 /* calculate something useful, like mean square displacements */
816 calc_corr(curr, i, gnx[i], index[i], xa[cur], (gnx_com != NULL), com,
824 while (read_next_x(oenv, status, &t, x[cur], box));
825 fprintf(stderr, "\nUsed %d restart points spaced %g %s over %g %s\n\n",
827 output_env_conv_time(oenv, dt), output_env_get_time_unit(oenv),
828 output_env_conv_time(oenv, curr->time[curr->nframes-1]),
829 output_env_get_time_unit(oenv) );
833 gmx_rmpbc_done(gpbc);
841 static void index_atom2mol(int *n, int *index, t_block *mols)
843 int nat, i, nmol, mol, j;
851 while (index[i] > mols->index[mol])
856 gmx_fatal(FARGS, "Atom index out of range: %d", index[i]+1);
859 for (j = mols->index[mol]; j < mols->index[mol+1]; j++)
861 if (i >= nat || index[i] != j)
863 gmx_fatal(FARGS, "The index group does not consist of whole molecules");
870 fprintf(stderr, "Split group of %d atoms into %d molecules\n", nat, nmol);
875 void do_corr(const char *trx_file, const char *ndx_file, const char *msd_file,
876 const char *mol_file, const char *pdb_file, real t_pdb,
877 int nrgrp, t_topology *top, int ePBC,
878 gmx_bool bTen, gmx_bool bMW, gmx_bool bRmCOMM,
879 int type, real dim_factor, int axis,
880 real dt, real beginfit, real endfit, const output_env_t oenv)
883 int *gnx; /* the selected groups' sizes */
884 atom_id **index; /* selected groups' indices */
886 int i, i0, i1, j, N, nat_trx;
887 real *DD, *SigmaD, a, a2, b, r, chi2;
890 int *gnx_com = NULL; /* the COM removal group size */
891 atom_id **index_com = NULL; /* the COM removal group atom indices */
892 char **grpname_com = NULL; /* the COM removal group name */
896 snew(grpname, nrgrp);
898 fprintf(stderr, "\nSelect a group to calculate mean squared displacement for:\n");
899 get_index(&top->atoms, ndx_file, nrgrp, gnx, index, grpname);
905 snew(grpname_com, 1);
907 fprintf(stderr, "\nNow select a group for center of mass removal:\n");
908 get_index(&top->atoms, ndx_file, 1, gnx_com, index_com, grpname_com);
913 index_atom2mol(&gnx[0], index[0], &top->mols);
916 msd = init_corr(nrgrp, type, axis, dim_factor,
917 mol_file == NULL ? 0 : gnx[0], bTen, bMW, dt, top,
921 corr_loop(msd, trx_file, top, ePBC, mol_file ? gnx[0] : 0, gnx, index,
922 (mol_file != NULL) ? calc1_mol : (bMW ? calc1_mw : calc1_norm),
923 bTen, gnx_com, index_com, dt, t_pdb,
924 pdb_file ? &x : NULL, box, oenv);
926 /* Correct for the number of points */
927 for (j = 0; (j < msd->ngrp); j++)
929 for (i = 0; (i < msd->nframes); i++)
931 msd->data[j][i] /= msd->ndata[j][i];
934 msmul(msd->datam[j][i], 1.0/msd->ndata[j][i], msd->datam[j][i]);
941 if (pdb_file && x == NULL)
943 fprintf(stderr, "\nNo frame found need time tpdb = %g ps\n"
944 "Can not write %s\n\n", t_pdb, pdb_file);
947 top->atoms.nr = nat_trx;
948 printmol(msd, mol_file, pdb_file, index[0], top, x, ePBC, box, oenv);
957 i0 = (int)(0.1*(msd->nframes - 1) + 0.5);
958 beginfit = msd->time[i0];
962 for (i0 = 0; i0 < msd->nframes && msd->time[i0] < beginfit; i0++)
970 i1 = (int)(0.9*(msd->nframes - 1) + 0.5) + 1;
971 endfit = msd->time[i1-1];
975 for (i1 = i0; i1 < msd->nframes && msd->time[i1] <= endfit; i1++)
980 fprintf(stdout, "Fitting from %g to %g %s\n\n", beginfit, endfit,
981 output_env_get_time_unit(oenv));
986 fprintf(stdout, "Not enough points for fitting (%d).\n"
987 "Can not determine the diffusion constant.\n", N);
992 snew(SigmaD, msd->ngrp);
993 for (j = 0; j < msd->ngrp; j++)
997 lsq_y_ax_b(N/2, &(msd->time[i0]), &(msd->data[j][i0]), &a, &b, &r, &chi2);
998 lsq_y_ax_b(N/2, &(msd->time[i0+N/2]), &(msd->data[j][i0+N/2]), &a2, &b, &r, &chi2);
999 SigmaD[j] = fabs(a-a2);
1005 lsq_y_ax_b(N, &(msd->time[i0]), &(msd->data[j][i0]), &(DD[j]), &b, &r, &chi2);
1006 DD[j] *= FACTOR/msd->dim_factor;
1007 SigmaD[j] *= FACTOR/msd->dim_factor;
1008 if (DD[j] > 0.01 && DD[j] < 1e4)
1010 fprintf(stdout, "D[%10s] %.4f (+/- %.4f) 1e-5 cm^2/s\n",
1011 grpname[j], DD[j], SigmaD[j]);
1015 fprintf(stdout, "D[%10s] %.4g (+/- %.4g) 1e-5 cm^2/s\n",
1016 grpname[j], DD[j], SigmaD[j]);
1020 /* Print mean square displacement */
1021 corr_print(msd, bTen, msd_file,
1022 "Mean Square Displacement",
1024 msd->time[msd->nframes-1], beginfit, endfit, DD, SigmaD, grpname, oenv);
1027 int gmx_msd(int argc, char *argv[])
1029 const char *desc[] = {
1030 "[THISMODULE] computes the mean square displacement (MSD) of atoms from",
1031 "a set of initial positions. This provides an easy way to compute",
1032 "the diffusion constant using the Einstein relation.",
1033 "The time between the reference points for the MSD calculation",
1034 "is set with [TT]-trestart[tt].",
1035 "The diffusion constant is calculated by least squares fitting a",
1036 "straight line (D*t + c) through the MSD(t) from [TT]-beginfit[tt] to",
1037 "[TT]-endfit[tt] (note that t is time from the reference positions,",
1038 "not simulation time). An error estimate given, which is the difference",
1039 "of the diffusion coefficients obtained from fits over the two halves",
1040 "of the fit interval.[PAR]",
1041 "There are three, mutually exclusive, options to determine different",
1042 "types of mean square displacement: [TT]-type[tt], [TT]-lateral[tt]",
1043 "and [TT]-ten[tt]. Option [TT]-ten[tt] writes the full MSD tensor for",
1044 "each group, the order in the output is: trace xx yy zz yx zx zy.[PAR]",
1045 "If [TT]-mol[tt] is set, [THISMODULE] plots the MSD for individual molecules",
1046 "(including making molecules whole across periodic boundaries): ",
1047 "for each individual molecule a diffusion constant is computed for ",
1048 "its center of mass. The chosen index group will be split into ",
1050 "The default way to calculate a MSD is by using mass-weighted averages.",
1051 "This can be turned off with [TT]-nomw[tt].[PAR]",
1052 "With the option [TT]-rmcomm[tt], the center of mass motion of a ",
1053 "specific group can be removed. For trajectories produced with ",
1054 "GROMACS this is usually not necessary, ",
1055 "as [gmx-mdrun] usually already removes the center of mass motion.",
1056 "When you use this option be sure that the whole system is stored",
1057 "in the trajectory file.[PAR]",
1058 "The diffusion coefficient is determined by linear regression of the MSD,",
1059 "where, unlike for the normal output of D, the times are weighted",
1060 "according to the number of reference points, i.e. short times have",
1061 "a higher weight. Also when [TT]-beginfit[tt]=-1,fitting starts at 10%",
1062 "and when [TT]-endfit[tt]=-1, fitting goes to 90%.",
1063 "Using this option one also gets an accurate error estimate",
1064 "based on the statistics between individual molecules.",
1065 "Note that this diffusion coefficient and error estimate are only",
1066 "accurate when the MSD is completely linear between",
1067 "[TT]-beginfit[tt] and [TT]-endfit[tt].[PAR]",
1068 "Option [TT]-pdb[tt] writes a [TT].pdb[tt] file with the coordinates of the frame",
1069 "at time [TT]-tpdb[tt] with in the B-factor field the square root of",
1070 "the diffusion coefficient of the molecule.",
1071 "This option implies option [TT]-mol[tt]."
1073 static const char *normtype[] = { NULL, "no", "x", "y", "z", NULL };
1074 static const char *axtitle[] = { NULL, "no", "x", "y", "z", NULL };
1075 static int ngroup = 1;
1076 static real dt = 10;
1077 static real t_pdb = 0;
1078 static real beginfit = -1;
1079 static real endfit = -1;
1080 static gmx_bool bTen = FALSE;
1081 static gmx_bool bMW = TRUE;
1082 static gmx_bool bRmCOMM = FALSE;
1084 { "-type", FALSE, etENUM, {normtype},
1085 "Compute diffusion coefficient in one direction" },
1086 { "-lateral", FALSE, etENUM, {axtitle},
1087 "Calculate the lateral diffusion in a plane perpendicular to" },
1088 { "-ten", FALSE, etBOOL, {&bTen},
1089 "Calculate the full tensor" },
1090 { "-ngroup", FALSE, etINT, {&ngroup},
1091 "Number of groups to calculate MSD for" },
1092 { "-mw", FALSE, etBOOL, {&bMW},
1093 "Mass weighted MSD" },
1094 { "-rmcomm", FALSE, etBOOL, {&bRmCOMM},
1095 "Remove center of mass motion" },
1096 { "-tpdb", FALSE, etTIME, {&t_pdb},
1097 "The frame to use for option [TT]-pdb[tt] (%t)" },
1098 { "-trestart", FALSE, etTIME, {&dt},
1099 "Time between restarting points in trajectory (%t)" },
1100 { "-beginfit", FALSE, etTIME, {&beginfit},
1101 "Start time for fitting the MSD (%t), -1 is 10%" },
1102 { "-endfit", FALSE, etTIME, {&endfit},
1103 "End time for fitting the MSD (%t), -1 is 90%" }
1107 { efTRX, NULL, NULL, ffREAD },
1108 { efTPS, NULL, NULL, ffREAD },
1109 { efNDX, NULL, NULL, ffOPTRD },
1110 { efXVG, NULL, "msd", ffWRITE },
1111 { efXVG, "-mol", "diff_mol", ffOPTWR },
1112 { efPDB, "-pdb", "diff_mol", ffOPTWR }
1114 #define NFILE asize(fnm)
1120 const char *trx_file, *tps_file, *ndx_file, *msd_file, *mol_file, *pdb_file;
1127 if (!parse_common_args(&argc, argv,
1128 PCA_CAN_VIEW | PCA_CAN_BEGIN | PCA_CAN_END | PCA_TIME_UNIT,
1129 NFILE, fnm, asize(pa), pa, asize(desc), desc, 0, NULL, &oenv))
1133 trx_file = ftp2fn_null(efTRX, NFILE, fnm);
1134 tps_file = ftp2fn_null(efTPS, NFILE, fnm);
1135 ndx_file = ftp2fn_null(efNDX, NFILE, fnm);
1136 msd_file = ftp2fn_null(efXVG, NFILE, fnm);
1137 pdb_file = opt2fn_null("-pdb", NFILE, fnm);
1140 mol_file = opt2fn("-mol", NFILE, fnm);
1144 mol_file = opt2fn_null("-mol", NFILE, fnm);
1149 gmx_fatal(FARGS, "Must have at least 1 group (now %d)", ngroup);
1151 if (mol_file && ngroup > 1)
1153 gmx_fatal(FARGS, "With molecular msd can only have 1 group (now %d)",
1161 fprintf(stderr, "Calculating diffusion coefficients for molecules.\n");
1164 if (normtype[0][0] != 'n')
1166 type = normtype[0][0] - 'x' + X; /* See defines above */
1174 if ((type == NORMAL) && (axtitle[0][0] != 'n'))
1178 axis = (axtitle[0][0] - 'x'); /* See defines above */
1185 if (bTen && type != NORMAL)
1187 gmx_fatal(FARGS, "Can only calculate the full tensor for 3D msd");
1190 bTop = read_tps_conf(tps_file, title, &top, &ePBC, &xdum, NULL, box, bMW || bRmCOMM);
1191 if (mol_file && !bTop)
1194 "Could not read a topology from %s. Try a tpr file instead.",
1198 do_corr(trx_file, ndx_file, msd_file, mol_file, pdb_file, t_pdb, ngroup,
1199 &top, ePBC, bTen, bMW, bRmCOMM, type, dim_factor, axis, dt, beginfit, endfit,
1202 view_all(oenv, NFILE, fnm);