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44 #include "gromacs/commandline/pargs.h"
45 #include "gromacs/commandline/viewit.h"
46 #include "gromacs/correlationfunctions/autocorr.h"
47 #include "gromacs/fft/fft.h"
48 #include "gromacs/fileio/confio.h"
49 #include "gromacs/fileio/trxio.h"
50 #include "gromacs/fileio/xvgr.h"
51 #include "gromacs/gmxana/gmx_ana.h"
52 #include "gromacs/gmxana/gstat.h"
53 #include "gromacs/math/functions.h"
54 #include "gromacs/math/units.h"
55 #include "gromacs/math/utilities.h"
56 #include "gromacs/math/vec.h"
57 #include "gromacs/topology/index.h"
58 #include "gromacs/topology/topology.h"
59 #include "gromacs/trajectory/trajectoryframe.h"
60 #include "gromacs/utility/arraysize.h"
61 #include "gromacs/utility/fatalerror.h"
62 #include "gromacs/utility/futil.h"
63 #include "gromacs/utility/smalloc.h"
65 static void index_atom2mol(int* n, int* index, const t_block* mols)
67 int nat, i, nmol, mol, j;
75 while (index[i] > mols->index[mol])
80 gmx_fatal(FARGS, "Atom index out of range: %d", index[i] + 1);
83 for (j = mols->index[mol]; j < mols->index[mol + 1]; j++)
85 if (i >= nat || index[i] != j)
87 gmx_fatal(FARGS, "The index group does not consist of whole molecules");
94 fprintf(stderr, "\nSplit group of %d atoms into %d molecules\n", nat, nmol);
99 static void precalc(const t_topology& top, real normm[])
105 for (i = 0; i < top.mols.nr; i++)
107 k = top.mols.index[i];
108 l = top.mols.index[i + 1];
111 for (j = k; j < l; j++)
113 mtot += top.atoms.atom[j].m;
116 for (j = k; j < l; j++)
118 normm[j] = top.atoms.atom[j].m / mtot;
123 static void calc_spectrum(int n, const real c[], real dt, const char* fn, gmx_output_env_t* oenv, gmx_bool bRecip)
129 real nu, omega, recip_fac;
132 for (i = 0; (i < n); i++)
137 if ((status = gmx_fft_init_1d_real(&fft, n, GMX_FFT_FLAG_NONE)) != 0)
139 gmx_fatal(FARGS, "Invalid fft return status %d", status);
141 if ((status = gmx_fft_1d_real(fft, GMX_FFT_REAL_TO_COMPLEX, data, data)) != 0)
143 gmx_fatal(FARGS, "Invalid fft return status %d", status);
145 fp = xvgropen(fn, "Vibrational Power Spectrum",
146 bRecip ? "\\f{12}w\\f{4} (cm\\S-1\\N)" : "\\f{12}n\\f{4} (ps\\S-1\\N)", "a.u.", oenv);
147 /* This is difficult.
148 * The length of the ACF is dt (as passed to this routine).
149 * We pass the vacf with N time steps from 0 to dt.
150 * That means that after FFT we have lowest frequency = 1/dt
151 * then 1/(2 dt) etc. (this is the X-axis of the data after FFT).
152 * To convert to 1/cm we need to have to realize that
153 * E = hbar w = h nu = h c/lambda. We want to have reciprokal cm
154 * on the x-axis, that is 1/lambda, so we then have
155 * 1/lambda = nu/c. Since nu has units of 1/ps and c has gromacs units
156 * of nm/ps, we need to multiply by 1e7.
157 * The timestep between saving the trajectory is
158 * 1e7 is to convert nanometer to cm
160 recip_fac = bRecip ? (1e7 / SPEED_OF_LIGHT) : 1.0;
161 for (i = 0; (i < n); i += 2)
164 omega = nu * recip_fac;
165 /* Computing the square magnitude of a complex number, since this is a power
168 fprintf(fp, "%10g %10g\n", omega, gmx::square(data[i]) + gmx::square(data[i + 1]));
171 gmx_fft_destroy(fft);
175 int gmx_velacc(int argc, char* argv[])
177 const char* desc[] = { "[THISMODULE] computes the velocity autocorrelation function.",
178 "When the [TT]-m[tt] option is used, the momentum autocorrelation",
179 "function is calculated.[PAR]",
180 "With option [TT]-mol[tt] the velocity autocorrelation function of",
181 "molecules is calculated. In this case the index group should consist",
182 "of molecule numbers instead of atom numbers.[PAR]",
183 "By using option [TT]-os[tt] you can also extract the estimated",
184 "(vibrational) power spectrum, which is the Fourier transform of the",
185 "velocity autocorrelation function.",
186 "Be sure that your trajectory contains frames with velocity information",
187 "(i.e. [TT]nstvout[tt] was set in your original [REF].mdp[ref] file),",
188 "and that the time interval between data collection points is",
189 "much shorter than the time scale of the autocorrelation." };
191 static gmx_bool bMass = FALSE, bMol = FALSE, bRecip = TRUE;
193 { "-m", FALSE, etBOOL, { &bMass }, "Calculate the momentum autocorrelation function" },
194 { "-recip", FALSE, etBOOL, { &bRecip }, "Use cm^-1 on X-axis instead of 1/ps for spectra." },
195 { "-mol", FALSE, etBOOL, { &bMol }, "Calculate the velocity acf of molecules" }
202 gmx_bool bTPS = FALSE, bTop = FALSE;
206 /* t0, t1 are the beginning and end time respectively.
207 * dt is the time step, mass is temp variable for atomic mass.
209 real t0, t1, dt, mass;
211 int counter, n_alloc, i, j, counter_dim, k, l;
213 /* Array for the correlation function */
215 real* normm = nullptr;
216 gmx_output_env_t* oenv;
220 t_filenm fnm[] = { { efTRN, "-f", nullptr, ffREAD },
221 { efTPS, nullptr, nullptr, ffOPTRD },
222 { efNDX, nullptr, nullptr, ffOPTRD },
223 { efXVG, "-o", "vac", ffWRITE },
224 { efXVG, "-os", "spectrum", ffOPTWR } };
225 #define NFILE asize(fnm)
230 ppa = add_acf_pargs(&npargs, pa);
231 if (!parse_common_args(&argc, argv, PCA_CAN_VIEW | PCA_CAN_TIME, NFILE, fnm, npargs, ppa,
232 asize(desc), desc, 0, nullptr, &oenv))
240 bTPS = ftp2bSet(efTPS, NFILE, fnm) || !ftp2bSet(efNDX, NFILE, fnm);
245 bTop = read_tps_conf(ftp2fn(efTPS, NFILE, fnm), &top, &ePBC, nullptr, nullptr, box, TRUE);
246 get_index(&top.atoms, ftp2fn_null(efNDX, NFILE, fnm), 1, &gnx, &index, &grpname);
250 rd_index(ftp2fn(efNDX, NFILE, fnm), 1, &gnx, &index, &grpname);
257 gmx_fatal(FARGS, "Need a topology to determine the molecules");
259 snew(normm, top.atoms.nr);
261 index_atom2mol(&gnx, index, &top.mols);
264 /* Correlation stuff */
266 for (i = 0; (i < gnx); i++)
271 read_first_frame(oenv, &status, ftp2fn(efTRN, NFILE, fnm), &fr, TRX_NEED_V);
278 if (counter >= n_alloc)
281 for (i = 0; i < gnx; i++)
283 srenew(c1[i], DIM * n_alloc);
286 counter_dim = DIM * counter;
289 for (i = 0; i < gnx; i++)
292 k = top.mols.index[index[i]];
293 l = top.mols.index[index[i] + 1];
294 for (j = k; j < l; j++)
298 mass = top.atoms.atom[j].m;
304 mv_mol[XX] += mass * fr.v[j][XX];
305 mv_mol[YY] += mass * fr.v[j][YY];
306 mv_mol[ZZ] += mass * fr.v[j][ZZ];
308 c1[i][counter_dim + XX] = mv_mol[XX];
309 c1[i][counter_dim + YY] = mv_mol[YY];
310 c1[i][counter_dim + ZZ] = mv_mol[ZZ];
315 for (i = 0; i < gnx; i++)
319 mass = top.atoms.atom[index[i]].m;
325 c1[i][counter_dim + XX] = mass * fr.v[index[i]][XX];
326 c1[i][counter_dim + YY] = mass * fr.v[index[i]][YY];
327 c1[i][counter_dim + ZZ] = mass * fr.v[index[i]][ZZ];
334 } while (read_next_frame(oenv, status, &fr));
340 /* Compute time step between frames */
341 dt = (t1 - t0) / (counter - 1);
342 do_autocorr(opt2fn("-o", NFILE, fnm), oenv,
343 bMass ? "Momentum Autocorrelation Function" : "Velocity Autocorrelation Function",
344 counter, gnx, c1, dt, eacVector, TRUE);
346 do_view(oenv, opt2fn("-o", NFILE, fnm), "-nxy");
348 if (opt2bSet("-os", NFILE, fnm))
350 calc_spectrum(counter / 2, (c1[0]), (t1 - t0) / 2, opt2fn("-os", NFILE, fnm), oenv, bRecip);
351 do_view(oenv, opt2fn("-os", NFILE, fnm), "-nxy");
356 fprintf(stderr, "Not enough frames in trajectory - no output generated.\n");