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bbee5fedb0
* Fix copyright * Address review comments Removed finite diff from RDKit headers Used explicit coordinates
54 lines
1.3 KiB
C++
54 lines
1.3 KiB
C++
//
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// Copyright (C) 2026 Greg Landrum and other RDKit contributors
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//
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// @@ All Rights Reserved @@
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// This file is part of the RDKit.
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// The contents are covered by the terms of the BSD license
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// which is included in the file license.txt, found at the root
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// of the RDKit source tree.
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//
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#include "FiniteDifference.h"
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#include "ForceField.h"
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#include <algorithm>
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#include <cmath>
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#include <vector>
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namespace ForceFields {
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double calcFiniteDifference(ForceField &ff, double stepSize) {
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const unsigned int dim = ff.dimension();
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const unsigned int nPoints = ff.numPoints();
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const unsigned int nCoords = dim * nPoints;
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std::vector<double> analyticGrad(nCoords, 0.0);
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ff.calcGrad(analyticGrad.data());
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std::vector<double> pos(nCoords);
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for (unsigned int i = 0; i < nPoints; ++i) {
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for (unsigned int d = 0; d < dim; ++d) {
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pos[i * dim + d] = (*ff.positions()[i])[d];
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}
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}
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double maxDelta = 0.0;
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for (unsigned int i = 0; i < nCoords; ++i) {
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double orig = pos[i];
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pos[i] = orig + stepSize;
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double ePlus = ff.calcEnergy(pos.data());
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pos[i] = orig - stepSize;
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double eMinus = ff.calcEnergy(pos.data());
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pos[i] = orig;
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double fdGrad = (ePlus - eMinus) / (2.0 * stepSize);
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maxDelta = std::max(maxDelta, std::abs(fdGrad - analyticGrad[i]));
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}
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return maxDelta;
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}
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} // namespace ForceFields
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