PatersonBudd.cc

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/* Copyright (C) 2015, 2023, 2025 PISM Authors
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#include "pism/rheology/PatersonBudd.hh"
#include <cmath>   // for pow
#include <memory>  // for shared_ptr
 
namespace pism {
namespace rheology {
 
// PatersonBudd
 
PatersonBudd::PatersonBudd(double exponent, const Config &config,
                           std::shared_ptr<EnthalpyConverter> ec)
    : FlowLaw(exponent, config, ec) {
  m_name = "Paterson-Budd";
}
 
/*! Converts enthalpy to temperature and uses the Paterson-Budd formula. */
double PatersonBudd::softness_impl(double E, double pressure) const {
  double T_pa = m_EC->pressure_adjusted_temperature(E, pressure);
  return softness_from_temp(T_pa);
}
 
/*! Converts enthalpy to temperature and calls flow_from_temp. */
double PatersonBudd::flow_impl(double stress, double E,
                               double pressure, double gs) const {
  double temp = m_EC->temperature(E, pressure);
  return flow_from_temp(stress, temp, pressure, gs);
}
 
//! The flow law (temperature-dependent version).
double PatersonBudd::flow_from_temp(double stress, double temp,
                                    double pressure, double /*gs*/) const {
  // pressure-adjusted temperature:
  const double T_pa = temp + (m_beta_CC_grad / m_rho_g) * pressure;
  return softness_from_temp(T_pa) * pow(stress, m_n-1);
}
 
double PatersonBudd::softness_from_temp(double T_pa) const {
  return softness_paterson_budd(T_pa);
}
 
double PatersonBudd::hardness_from_temp(double T_pa) const {
  return pow(softness_from_temp(T_pa), m_hardness_power);
}
 
} // end of namespace rheology
} // end of namespace pism