mirror of https://github.com/lammps/lammps.git
344 lines
11 KiB
C++
344 lines
11 KiB
C++
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/****************************************************************
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* abf_integrate *
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* Integrate n-dimensional PMF from discrete gradient grid *
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* Jerome Henin <jerome.henin@ibpc.fr> *
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****************************************************************/
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#include "abf_data.h"
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#include <fstream>
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#include <string>
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#include <cstring>
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#include <cstdlib>
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#include <ctime>
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#include <cmath>
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char *parse_cl(int argc, char *argv[], unsigned int *nsteps, double *temp,
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bool * meta, double *hill, double *hill_fact);
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double compute_deviation(ABFdata * data, bool meta, double kT);
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int main(int argc, char *argv[])
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{
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char *data_file;
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char *out_file;
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unsigned int step, nsteps, total, out_freq;
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int *pos, *dpos, *newpos;
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unsigned int *histogram;
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const double *grad, *newgrad;
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unsigned int offset, newoffset;
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int not_accepted;
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double dA;
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double temp;
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double mbeta;
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bool meta;
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double hill, hill_fact, hill_min;
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double rmsd, rmsd_old, rmsd_rel_change, convergence_limit;
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bool converged;
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unsigned int scale_hill_step;
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// Setting default values
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nsteps = 0;
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temp = 500;
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meta = true;
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hill = 0.01;
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hill_fact = 0.5;
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hill_min = 0.0005;
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convergence_limit = -0.001;
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if (!(data_file = parse_cl(argc, argv, &nsteps, &temp, &meta, &hill, &hill_fact))) {
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std::cerr << "\nabf_integrate: MC-based integration of multidimensional free energy gradient\n";
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std::cerr << "Version 20110511\n\n";
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std::cerr << "Syntax: " << argv[0] <<
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" <filename> [-n <nsteps>] [-t <temp>] [-m [0|1] (metadynamics)]"
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" [-h <hill_height>] [-f <variable_hill_factor>]\n\n";
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exit(1);
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}
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if (meta) {
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std::cout << "\nUsing metadynamics-style sampling with hill height: " << hill << "\n";
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if (hill_fact) {
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std::cout << "Varying hill height by factor " << hill_fact << "\n";
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}
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} else {
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std::cout << "\nUsing unbiased MC sampling\n";
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}
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if (nsteps) {
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std::cout << "Sampling " << nsteps << " steps at temperature " << temp << "\n\n";
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out_freq = nsteps / 10;
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scale_hill_step = nsteps / 2;
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converged = true;
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} else {
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std::cout << "Sampling until convergence at temperature " << temp << "\n\n";
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out_freq = 1000000;
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converged = false;
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}
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// Inverse temperature in (kcal/mol)-1
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mbeta = -1 / (0.001987 * temp);
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ABFdata data(data_file);
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if (!nsteps) {
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scale_hill_step = 2000 * data.scalar_dim;
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nsteps = 2 * scale_hill_step;
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std::cout << "Setting minimum number of steps to " << nsteps << "\n";
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}
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srand(time(NULL));
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pos = new int[data.Nvars];
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dpos = new int[data.Nvars];
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newpos = new int[data.Nvars];
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do {
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for (int i = 0; i < data.Nvars; i++) {
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pos[i] = rand() % data.sizes[i];
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}
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offset = data.offset(pos);
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} while ( !data.allowed (offset) );
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rmsd = compute_deviation(&data, meta, 0.001987 * temp);
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std::cout << "\nInitial gradient RMS is " << rmsd << "\n";
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total = 0;
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for (step = 1; (step <= nsteps || !converged); step++) {
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if ( step % out_freq == 0) {
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rmsd_old = rmsd;
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rmsd = compute_deviation(&data, meta, 0.001987 * temp);
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rmsd_rel_change = (rmsd - rmsd_old) / (rmsd_old * double (out_freq)) * 1000000.0;
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std::cout << "Step " << step << " ; gradient RMSD is " << rmsd
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<< " ; relative change per 1M steps " << rmsd_rel_change;
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if ( rmsd_rel_change > convergence_limit && step >= nsteps ) {
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converged = true;
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}
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if (meta && hill_fact && step > scale_hill_step && hill > hill_min ) {
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hill *= hill_fact;
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std::cout << " - changing hill height to " << hill << "\n";
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} else {
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std::cout << "\n";
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}
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}
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offset = data.offset(pos);
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data.histogram[offset]++;
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if (meta) {
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data.bias[offset] += hill;
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}
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grad = data.gradients + offset * data.Nvars;
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not_accepted = 1;
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while (not_accepted) {
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dA = 0.0;
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total++;
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for (int i = 0; i < data.Nvars; i++) {
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dpos[i] = rand() % 3 - 1;
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newpos[i] = pos[i] + dpos[i];
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data.wrap(newpos[i], i);
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if (newpos[i] == pos[i])
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dpos[i] = 0;
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if (dpos[i]) {
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dA += grad[i] * dpos[i] * data.widths[i];
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// usefulness of the interpolation below depends on
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// where the grid points are for the histogram wrt to the gradients
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// If done, it has to be done in all directions
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// the line below is useless
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//dA += 0.5 * (newgrad[i] + grad[i]) * dpos[i] * data.widths[i];
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}
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}
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newoffset = data.offset(newpos);
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if (meta) {
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dA += data.bias[newoffset] - data.bias[offset];
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}
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if ( data.allowed (newoffset) && (((float) rand()) / RAND_MAX < exp(mbeta * dA)) ) {
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// Accept move
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for (int i = 0; i < data.Nvars; i++) {
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pos[i] = newpos[i];
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not_accepted = 0;
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}
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}
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}
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}
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std::cout << "Run " << total << " total iterations; acceptance ratio is "
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<< double (step) / double (total)
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<< " ; final gradient RMSD is " << compute_deviation(&data, meta, 0.001987 * temp) << "\n";
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out_file = new char[strlen(data_file) + 8];
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if (meta) {
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sprintf(out_file, "%s.pmf", data_file);
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std::cout << "Writing PMF to file " << out_file << "\n";
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data.write_bias(out_file);
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}
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// TODO write a PMF for unbiased MC, too...
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sprintf(out_file, "%s.histo", data_file);
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std::cout << "Writing sampling histogram to file " << out_file << "\n";
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data.write_histogram(out_file);
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sprintf(out_file, "%s.est", data_file);
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std::cout << "Writing estimated FE gradient to file " << out_file << "\n";
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data.write_field(data.estimate, out_file);
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sprintf(out_file, "%s.dev", data_file);
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std::cout << "Writing FE gradient deviation to file " << out_file << "\n\n";
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data.write_field(data.deviation, out_file);
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delete [] pos;
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delete [] dpos;
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delete [] newpos;
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delete [] out_file;
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exit(0);
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}
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double compute_deviation(ABFdata * data, bool meta, double kT)
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{
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// Computing deviation between gradients differentiated from pmf
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// and input data
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// NOTE: this is mostly for output, hence NOT performance-critical
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double *dev = data->deviation;
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double *est = data->estimate;
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const double *grad = data->gradients;
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int *pos, *dpos, *newpos;
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double rmsd = 0.0;
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unsigned int offset, newoffset;
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double sum;
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int c;
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bool moved;
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unsigned int norm = 0; // number of data points summmed
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pos = new int[data->Nvars];
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dpos = new int[data->Nvars];
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newpos = new int[data->Nvars];
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for (int i = 0; i < data->Nvars; i++)
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pos[i] = 0;
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for (offset = 0; offset < data->scalar_dim; offset++) {
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for (int i = data->Nvars - 1; i > 0; i--) {
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if (pos[i] == data->sizes[i]) {
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pos[i] = 0;
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pos[i - 1]++;
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}
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}
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if (data->allowed (offset)) {
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for (int i = 0; i < data->Nvars; i++)
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newpos[i] = pos[i];
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for (int i = 0; i < data->Nvars; i++) {
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est[i] = 0.0;
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sum = 0.0; // sum of finite differences on two sides (if not on edge of the grid)
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c = 0; // count of summed values
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newpos[i] = pos[i] - 1;
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moved = data->wrap(newpos[i], i);
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newoffset = data->offset(newpos);
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if ( moved && data->allowed (newoffset) ) {
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if (meta) {
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sum = (data->bias[newoffset] - data->bias[offset]) / data->widths[i];
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c++;
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} else {
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if (data->histogram[offset] && data->histogram[newoffset]) {
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sum = kT * log(double (data->histogram[newoffset]) /
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double (data->histogram[offset])) / data->widths[i];
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c++;
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}
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}
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}
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newpos[i] = pos[i] + 1;
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moved = data->wrap(newpos[i], i);
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newoffset = data->offset(newpos);
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if ( moved && data->allowed (newoffset) ) {
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if (meta) {
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sum += (data->bias[offset] - data->bias[newoffset]) / data->widths[i];
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c++;
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} else {
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if (data->histogram[offset] && data->histogram[newoffset]) {
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sum += kT * log(double (data->histogram[offset]) /
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double (data->histogram[newoffset])) / data->widths[i];
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c++;
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}
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}
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}
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newpos[i] = pos[i]; // Go back to initial position for next dimension
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est[i] = (c ? sum/double(c) : 0.0);
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dev[i] = grad[i] - est[i];
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rmsd += dev[i] * dev[i];
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norm++;
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}
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}
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pos[data->Nvars - 1]++; // move on to next point
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est += data->Nvars;
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dev += data->Nvars;
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grad += data->Nvars;
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}
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delete [] pos;
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delete [] newpos;
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delete [] dpos;
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return sqrt(rmsd / norm);
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}
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char *parse_cl(int argc, char *argv[], unsigned int *nsteps, double *temp,
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bool * meta, double *hill, double *hill_fact)
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{
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char *filename = NULL;
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float f_temp, f_hill;
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int meta_int;
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// getting default value for the integer
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meta_int = (*meta ? 1 : 0);
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// "Syntax: " << argv[0] << " <filename> [-n <nsteps>] [-t <temp>] [-m [0|1] (metadynamics)] [-h <hill_height>]\n";
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if (argc < 2) {
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return NULL;
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}
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for (int i = 2; i + 1 < argc; i += 2) {
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if (argv[i][0] != '-') {
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return NULL;
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}
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switch (argv[i][1]) {
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case 'n':
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if (sscanf(argv[i + 1], "%u", nsteps) != 1)
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return NULL;
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break;
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case 't':
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if (sscanf(argv[i + 1], "%lf", temp) != 1)
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return NULL;
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break;
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case 'm':
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if (sscanf(argv[i + 1], "%u", &meta_int) != 1)
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return NULL;
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break;
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case 'h':
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if (sscanf(argv[i + 1], "%lf", hill) != 1)
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return NULL;
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break;
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case 'f':
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if (sscanf(argv[i + 1], "%lf", hill_fact) != 1)
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return NULL;
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break;
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default:
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return NULL;
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}
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}
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*meta = (meta_int != 0);
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return argv[1];
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}
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