single_seed.hpp

Go to the documentation of this file.

// SPDX-FileCopyrightText: 2025 VTT Technical Research Centre of Finland Ltd
// SPDX-License-Identifier: AGPL-3.0-or-later
 
#ifndef PFC_INITIAL_CONDITIONS_SINGLE_SEED_HPP
#define PFC_INITIAL_CONDITIONS_SINGLE_SEED_HPP
 
#include "../field_modifier.hpp"
#include "openpfc/field/operations.hpp"
 
namespace pfc {
 
class SingleSeed : public FieldModifier {
  double amp_eq, rho_seed;
 
public:
  void set_amplitude(double amplitude) { amp_eq = amplitude; }
  double get_amplitude() const { return amp_eq; }
 
  void set_density(double density) { rho_seed = density; }
  double get_density() const { return rho_seed; }
 
  void apply(Model &m, double) override {
    // Functional coordinate-space implementation using field::apply
    const double s = 1.0 / sqrt(2.0);
    const std::array<double, 3> q1 = {s, s, 0};
    const std::array<double, 3> q2 = {s, 0, s};
    const std::array<double, 3> q3 = {0, s, s};
    const std::array<double, 3> q4 = {s, 0, -s};
    const std::array<double, 3> q5 = {s, -s, 0};
    const std::array<double, 3> q6 = {0, s, -s};
    const std::array<std::array<double, 3>, 6> q = {q1, q2, q3, q4, q5, q6};
 
    const double r2 = pow(64.0, 2);
    const double amplitude = amp_eq;
    const double rho = rho_seed;
 
    pfc::field::apply(m, get_field_name(), [=](const pfc::Real3 &X) {
      const double x = X[0];
      const double y = X[1];
      const double z = X[2];
      if (x * x + y * y + z * z >= r2) {
        return 0.0; // Outside seed: leave as zero
      }
      double u = rho;
      for (int qi = 0; qi < 6; ++qi) {
        u += 2.0 * amplitude * std::cos(q[qi][0] * x + q[qi][1] * y + q[qi][2] * z);
      }
      return u;
    });
  }
};
 
} // namespace pfc
 
#endif // PFC_INITIAL_CONDITIONS_SINGLE_SEED_HPP