Files
lammps/lib/colvars/colvarbias_alb.cpp
Giacomo Fiorin f3cf407a21 Collected fixes and updates to Colvars library
This commit includes several fixes to moving restraints; also added is support
for runtime integration of 2D and 3D PMFs from ABF.

Mostly changes to existing member functions, with few additions in classes not
directly accessible by LAMMPS.  Also removed are calls to std::pow(), replaced
by a copy of MathSpecial::powint().

Relevant commits in Colvars repository:

7307b5c 2017-12-14 Doc improvements [Giacomo Fiorin]
7f86f37 2017-12-14 Allow K-changing restraints computing accumulated work; fix staged-k TI estimator [Giacomo Fiorin]
7c1c175 2017-12-14 Fix 1D ABF trying to do pABF [Jérôme Hénin]
b94aa7e 2017-11-16 Unify PMF output for 1D, 2D and 3D in ABF [Jérôme Hénin]
771a88f 2017-11-15 Poisson integration for all BC in 2d and 3d [Jérôme Hénin]
6af4d60 2017-12-01 Print message when issuing cv delete in VMD [Giacomo Fiorin]
4413972 2017-11-30 Check for homogeneous colvar to set it periodic [Jérôme Hénin]
95fe4b2 2017-11-06 Allow abf_integrate to start in bin with 1 sample [Jérôme Hénin]
06eea27 2017-10-23 Shorten a few constructs by using the power function [Giacomo Fiorin]
3165dfb 2017-10-20 Move includes of colvarproxy.h from headers to files [Giacomo Fiorin]
32a867b 2017-10-20 Add optimized powint function from LAMMPS headers [Giacomo Fiorin]
3ad070a 2017-10-20 Remove some unused includes, isolate calls to std::pow() [Giacomo Fiorin]
0aaf540 2017-10-20 Replace all calls to std::pow() where the exponent is not an integer [Giacomo Fiorin]
2018-02-23 08:34:53 -05:00

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C++

// -*- c++ -*-
// This file is part of the Collective Variables module (Colvars).
// The original version of Colvars and its updates are located at:
// https://github.com/colvars/colvars
// Please update all Colvars source files before making any changes.
// If you wish to distribute your changes, please submit them to the
// Colvars repository at GitHub.
#include <cstdlib>
#include "colvarmodule.h"
#include "colvarbias.h"
#include "colvarbias_alb.h"
#ifdef _MSC_VER
#if _MSC_VER <= 1700
#define copysign(A,B) _copysign(A,B)
double fmax(double A, double B) { return ( A > B ? A : B ); }
double fmin(double A, double B) { return ( A < B ? A : B ); }
#endif
#endif
/* Note about nomenclature. Force constant is called a coupling
* constant here to emphasize its changing in the code. Outwards,
* everything is called a force constant to keep it consistent with
* the rest of colvars.
*
*/
colvarbias_alb::colvarbias_alb(char const *key)
: colvarbias(key), update_calls(0), b_equilibration(true)
{
}
int colvarbias_alb::init(std::string const &conf)
{
colvarbias::init(conf);
enable(f_cvb_scalar_variables);
size_t i;
// get the initial restraint centers
colvar_centers.resize(num_variables());
means.resize(num_variables());
ssd.resize(num_variables()); //sum of squares of differences from mean
//setup force vectors
max_coupling_range.resize(num_variables());
max_coupling_rate.resize(num_variables());
coupling_accum.resize(num_variables());
set_coupling.resize(num_variables());
current_coupling.resize(num_variables());
coupling_rate.resize(num_variables());
enable(f_cvb_apply_force);
for (i = 0; i < num_variables(); i++) {
colvar_centers[i].type(colvars[i]->value());
//zero moments
means[i] = ssd[i] = 0;
//zero force some of the force vectors that aren't initialized
coupling_accum[i] = current_coupling[i] = 0;
}
if (get_keyval(conf, "centers", colvar_centers, colvar_centers)) {
for (i = 0; i < num_variables(); i++) {
colvar_centers[i].apply_constraints();
}
} else {
colvar_centers.clear();
cvm::fatal_error("Error: must define the initial centers of adaptive linear bias .\n");
}
if (colvar_centers.size() != num_variables())
cvm::fatal_error("Error: number of centers does not match "
"that of collective variables.\n");
if (!get_keyval(conf, "UpdateFrequency", update_freq, 0))
cvm::fatal_error("Error: must set updateFrequency for adaptive linear bias.\n");
//we split the time between updating and equilibrating
update_freq /= 2;
if (update_freq <= 1)
cvm::fatal_error("Error: must set updateFrequency to greater than 2.\n");
enable(f_cvb_history_dependent);
get_keyval(conf, "outputCenters", b_output_centers, false);
get_keyval(conf, "outputGradient", b_output_grad, false);
get_keyval(conf, "outputCoupling", b_output_coupling, true);
get_keyval(conf, "hardForceRange", b_hard_coupling_range, true);
//initial guess
if (!get_keyval(conf, "forceConstant", set_coupling, set_coupling))
for (i =0 ; i < num_variables(); i++)
set_coupling[i] = 0.;
//how we're going to increase to that point
for (i = 0; i < num_variables(); i++)
coupling_rate[i] = (set_coupling[i] - current_coupling[i]) / update_freq;
if (!get_keyval(conf, "forceRange", max_coupling_range, max_coupling_range)) {
//set to default
for (i = 0; i < num_variables(); i++) {
if (cvm::temperature() > 0)
max_coupling_range[i] = 3 * cvm::temperature() * cvm::boltzmann();
else
max_coupling_range[i] = 3 * cvm::boltzmann();
}
}
if (!get_keyval(conf, "rateMax", max_coupling_rate, max_coupling_rate)) {
//set to default
for (i = 0; i < num_variables(); i++) {
max_coupling_rate[i] = max_coupling_range[i] / (10 * update_freq);
}
}
if (cvm::debug())
cvm::log(" bias.\n");
return COLVARS_OK;
}
colvarbias_alb::~colvarbias_alb()
{
}
int colvarbias_alb::update()
{
bias_energy = 0.0;
update_calls++;
if (cvm::debug())
cvm::log("Updating the adaptive linear bias \""+this->name+"\".\n");
//log the moments of the CVs
// Force and energy calculation
bool finished_equil_flag = 1;
cvm::real delta;
for (size_t i = 0; i < num_variables(); i++) {
colvar_forces[i] = -1.0 * restraint_force(restraint_convert_k(current_coupling[i], colvars[i]->width),
colvars[i],
colvar_centers[i]);
bias_energy += restraint_potential(restraint_convert_k(current_coupling[i], colvars[i]->width),
colvars[i],
colvar_centers[i]);
if (!b_equilibration) {
//Welford, West, and Hanso online variance method
delta = static_cast<cvm::real>(colvars[i]->value()) - means[i];
means[i] += delta / update_calls;
ssd[i] += delta * (static_cast<cvm::real>(colvars[i]->value()) - means[i]);
} else {
//check if we've reached the setpoint
cvm::real const coupling_diff = current_coupling[i] - set_coupling[i];
if ((coupling_rate[i] == 0) ||
((coupling_diff*coupling_diff) < (coupling_rate[i]*coupling_rate[i]))) {
finished_equil_flag &= 1; //we continue equilibrating as long as we haven't reached all the set points
}
else {
current_coupling[i] += coupling_rate[i];
finished_equil_flag = 0;
}
//update max_coupling_range
if (!b_hard_coupling_range && fabs(current_coupling[i]) > max_coupling_range[i]) {
std::ostringstream logStream;
logStream << "Coupling constant for "
<< colvars[i]->name
<< " has exceeded coupling range of "
<< max_coupling_range[i]
<< ".\n";
max_coupling_range[i] *= 1.25;
logStream << "Expanding coupling range to " << max_coupling_range[i] << ".\n";
cvm::log(logStream.str());
}
}
}
if (b_equilibration && finished_equil_flag) {
b_equilibration = false;
update_calls = 0;
}
//now we update coupling constant, if necessary
if (!b_equilibration && update_calls == update_freq) {
//use estimated variance to take a step
cvm::real step_size = 0;
cvm::real temp;
//reset means and sum of squares of differences
for (size_t i = 0; i < num_variables(); i++) {
temp = 2. * (means[i] / (static_cast<cvm::real> (colvar_centers[i])) - 1) * ssd[i] / (update_calls - 1);
if (cvm::temperature() > 0)
step_size = temp / (cvm::temperature() * cvm::boltzmann());
else
step_size = temp / cvm::boltzmann();
means[i] = 0;
ssd[i] = 0;
//stochastic if we do that update or not
if (num_variables() == 1 || rand() < RAND_MAX / ((int) num_variables())) {
coupling_accum[i] += step_size * step_size;
current_coupling[i] = set_coupling[i];
set_coupling[i] += max_coupling_range[i] / sqrt(coupling_accum[i]) * step_size;
coupling_rate[i] = (set_coupling[i] - current_coupling[i]) / update_freq;
//set to the minimum rate and then put the sign back on it
coupling_rate[i] = copysign(fmin(fabs(coupling_rate[i]), max_coupling_rate[i]), coupling_rate[i]);
} else {
coupling_rate[i] = 0;
}
}
update_calls = 0;
b_equilibration = true;
}
return COLVARS_OK;
}
int colvarbias_alb::set_state_params(std::string const &conf)
{
if (!get_keyval(conf, "setCoupling", set_coupling))
cvm::fatal_error("Error: current setCoupling is missing from the restart.\n");
if (!get_keyval(conf, "currentCoupling", current_coupling))
cvm::fatal_error("Error: current setCoupling is missing from the restart.\n");
if (!get_keyval(conf, "maxCouplingRange", max_coupling_range))
cvm::fatal_error("Error: maxCouplingRange is missing from the restart.\n");
if (!get_keyval(conf, "couplingRate", coupling_rate))
cvm::fatal_error("Error: current setCoupling is missing from the restart.\n");
if (!get_keyval(conf, "couplingAccum", coupling_accum))
cvm::fatal_error("Error: couplingAccum is missing from the restart.\n");
if (!get_keyval(conf, "mean", means))
cvm::fatal_error("Error: current mean is missing from the restart.\n");
if (!get_keyval(conf, "ssd", ssd))
cvm::fatal_error("Error: current ssd is missing from the restart.\n");
if (!get_keyval(conf, "updateCalls", update_calls))
cvm::fatal_error("Error: current updateCalls is missing from the restart.\n");
if (!get_keyval(conf, "b_equilibration", b_equilibration))
cvm::fatal_error("Error: current updateCalls is missing from the restart.\n");
return COLVARS_OK;
}
std::string const colvarbias_alb::get_state_params() const
{
std::ostringstream os;
os << " setCoupling ";
size_t i;
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << set_coupling[i] << "\n";
}
os << " currentCoupling ";
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << current_coupling[i] << "\n";
}
os << " maxCouplingRange ";
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << max_coupling_range[i] << "\n";
}
os << " couplingRate ";
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << coupling_rate[i] << "\n";
}
os << " couplingAccum ";
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << coupling_accum[i] << "\n";
}
os << " mean ";
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << means[i] << "\n";
}
os << " ssd ";
for (i = 0; i < num_variables(); i++) {
os << std::setprecision(cvm::en_prec)
<< std::setw(cvm::en_width) << ssd[i] << "\n";
}
os << " updateCalls " << update_calls << "\n";
if (b_equilibration)
os << " b_equilibration yes\n";
else
os << " b_equilibration no\n";
return os.str();
}
std::ostream & colvarbias_alb::write_traj_label(std::ostream &os)
{
os << " ";
if (b_output_energy)
os << " E_"
<< cvm::wrap_string(this->name, cvm::en_width-2);
if (b_output_coupling)
for (size_t i = 0; i < current_coupling.size(); i++) {
os << " ForceConst_" << i
<<std::setw(cvm::en_width - 6 - (i / 10 + 1))
<< "";
}
if (b_output_grad)
for (size_t i = 0; i < means.size(); i++) {
os << "Grad_"
<< cvm::wrap_string(colvars[i]->name, cvm::cv_width - 4);
}
if (b_output_centers)
for (size_t i = 0; i < num_variables(); i++) {
size_t const this_cv_width = (colvars[i]->value()).output_width(cvm::cv_width);
os << " x0_"
<< cvm::wrap_string(colvars[i]->name, this_cv_width-3);
}
return os;
}
std::ostream & colvarbias_alb::write_traj(std::ostream &os)
{
os << " ";
if (b_output_energy)
os << " "
<< std::setprecision(cvm::en_prec) << std::setw(cvm::en_width)
<< bias_energy;
if (b_output_coupling)
for (size_t i = 0; i < current_coupling.size(); i++) {
os << " "
<< std::setprecision(cvm::en_prec) << std::setw(cvm::en_width)
<< current_coupling[i];
}
if (b_output_centers)
for (size_t i = 0; i < num_variables(); i++) {
os << " "
<< std::setprecision(cvm::cv_prec) << std::setw(cvm::cv_width)
<< colvar_centers[i];
}
if (b_output_grad)
for (size_t i = 0; i < means.size(); i++) {
os << " "
<< std::setprecision(cvm::cv_prec) << std::setw(cvm::cv_width)
<< -2. * (means[i] / (static_cast<cvm::real> (colvar_centers[i])) - 1) * ssd[i] / (fmax(update_calls,2) - 1);
}
return os;
}
cvm::real colvarbias_alb::restraint_potential(cvm::real k,
colvar const *x,
colvarvalue const &xcenter) const
{
return k * (x->value() - xcenter);
}
colvarvalue colvarbias_alb::restraint_force(cvm::real k,
colvar const *x,
colvarvalue const &xcenter) const
{
return k;
}
cvm::real colvarbias_alb::restraint_convert_k(cvm::real k,
cvm::real dist_measure) const
{
return k / dist_measure;
}