NoseHooverChain.cpp

/* -------------------------------------------------------------------------- *
 *                                   OpenMM                                   *
 * -------------------------------------------------------------------------- *
 * This is part of the OpenMM molecular simulation toolkit originating from   *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org.               *
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 * Portions copyright (c) 2019 Stanford University and the Authors.           *
 * Authors: Andreas Krämer and Andrew C. Simmonett                            *
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#include "openmm/NoseHooverChain.h"
#include "openmm/internal/NoseHooverChainImpl.h"
#include "openmm/OpenMMException.h"

using namespace OpenMM;

NoseHooverChain::NoseHooverChain(double defaultTemperature, double defaultCollisionFrequency, 
                                 int defaultNumDOFs, int defaultChainLength, int defaultNumMTS,
                                 int defaultNumYoshidaSuzuki, const std::string &defaultLabel,
                                 const std::vector<int>& thermostatedAtoms, const std::vector<int>& parentAtoms):
        defaultTemp(defaultTemperature), defaultFreq(defaultCollisionFrequency), defaultNumDOFs(defaultNumDOFs),
        defaultChainLength(defaultChainLength), defaultNumMTS(defaultNumMTS), defaultNumYS(defaultNumYoshidaSuzuki),
        defaultLabel(defaultLabel), thermostatedAtoms(thermostatedAtoms), parentAtoms(parentAtoms) 
{}

ForceImpl* NoseHooverChain::createImpl() const {
    return new NoseHooverChainImpl(*this);
}

std::vector<double> NoseHooverChain::getDefaultYoshidaSuzukiWeights() const {
    switch (defaultNumYS) {
        case 1:
            return {1};
        case 3:
            return {0.828981543588751, -0.657963087177502, 0.828981543588751};
        case 5:
            return {0.2967324292201065, 0.2967324292201065, -0.186929716880426, 0.2967324292201065,
                    0.2967324292201065};
        default:
            throw OpenMMException("The number of Yoshida-Suzuki weights must be 1,3, or 5.");
    }
}