NonlinearSystem.h

// Copyright 2024, UChicago Argonne, LLC
// All Rights Reserved
// Software Name: NEML2 -- the New Engineering material Model Library, version 2
// By: Argonne National Laboratory
// OPEN SOURCE LICENSE (MIT)
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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#pragma once
 
#include "neml2/tensors/Tensor.h"
#include "neml2/base/OptionSet.h"
 
namespace neml2
{
class NonlinearSystem
{
public:
  template <bool scaled>
  struct Res : public Tensor
  {
    Res() = default;
 
    explicit Res(const Tensor & r)
      : Tensor(r)
    {
    }
 
    explicit Res(const Res<!scaled> & r)
      : Tensor(r)
    {
    }
  };
 
  template <bool scaled>
  struct Jac : public Tensor
  {
    Jac() = default;
 
    explicit Jac(const Tensor & J)
      : Tensor(J)
    {
    }
 
    explicit Jac(const Jac<!scaled> & J)
      : Tensor(J)
    {
    }
  };
 
  template <bool scaled>
  struct Sol : public Tensor
  {
    Sol() = default;
 
    explicit Sol(const Tensor & u)
      : Tensor(u)
    {
    }
 
    explicit Sol(const Sol<!scaled> & u)
      : Tensor(u)
    {
    }
  };
 
  NonlinearSystem(const NonlinearSystem &) = default;
  NonlinearSystem(NonlinearSystem &&) noexcept = default;
  NonlinearSystem & operator=(const NonlinearSystem &) = delete;
  NonlinearSystem & operator=(NonlinearSystem &&) = delete;
  virtual ~NonlinearSystem() = default;
 
  static OptionSet expected_options();
  static void disable_automatic_scaling(OptionSet & options);
  static void enable_automatic_scaling(OptionSet & options);
 
  NonlinearSystem(const OptionSet & options);
 
  virtual void init_scaling(const Sol<false> & x, const bool verbose = false);
 
  Res<true> scale(const Res<false> & r) const;
  Res<false> unscale(const Res<true> & r) const;
  Jac<true> scale(const Jac<false> & J) const;
  Jac<false> unscale(const Jac<true> & J) const;
  Sol<true> scale(const Sol<false> & u) const;
  Sol<false> unscale(const Sol<true> & u) const;
 
  virtual void set_guess(const Sol<true> & x) final;
  virtual void set_guess(const Sol<false> & x) = 0;
  template <bool scaled>
  Res<scaled> residual();
  template <bool scaled>
  Res<scaled> residual(const Sol<scaled> & x);
  template <bool scaled>
  Jac<scaled> Jacobian();
  template <bool scaled>
  Jac<scaled> Jacobian(const Sol<scaled> & x);
  template <bool scaled>
  std::tuple<Res<scaled>, Jac<scaled>> residual_and_Jacobian();
  template <bool scaled>
  std::tuple<Res<scaled>, Jac<scaled>> residual_and_Jacobian(const Sol<scaled> & x);
 
protected:
  virtual void assemble(Res<false> * r, Jac<false> * J) = 0;
 
  const bool _autoscale;
 
  const Real _autoscale_tol;
 
  const unsigned int _autoscale_miter;
 
  bool _scaling_matrices_initialized;
 
  Tensor _row_scaling;
 
  Tensor _col_scaling;
 
private:
  void ensure_scaling_matrices_initialized_dbg() const;
};
 
// Implementation
 
template <bool scaled>
NonlinearSystem::Res<scaled>
NonlinearSystem::residual()
{
  Res<false> r;
  assemble(&r, nullptr);
  if constexpr (scaled)
    return scale(r);
  else
    return r;
}
 
template <bool scaled>
NonlinearSystem::Res<scaled>
NonlinearSystem::residual(const NonlinearSystem::Sol<scaled> & x)
{
  set_guess(x);
  return residual<scaled>();
}
 
template <bool scaled>
NonlinearSystem::Jac<scaled>
NonlinearSystem::Jacobian()
{
  Jac<false> J;
  assemble(nullptr, &J);
  if constexpr (scaled)
    return scale(J);
  else
    return J;
}
 
template <bool scaled>
NonlinearSystem::Jac<scaled>
NonlinearSystem::Jacobian(const NonlinearSystem::Sol<scaled> & x)
{
  set_guess(x);
  return Jacobian<scaled>();
}
 
template <bool scaled>
std::tuple<NonlinearSystem::Res<scaled>, NonlinearSystem::Jac<scaled>>
NonlinearSystem::residual_and_Jacobian()
{
  Res<false> r;
  Jac<false> J;
  assemble(&r, &J);
  if constexpr (scaled)
    return {scale(r), scale(J)};
  else
    return {r, J};
}
 
template <bool scaled>
std::tuple<NonlinearSystem::Res<scaled>, NonlinearSystem::Jac<scaled>>
NonlinearSystem::residual_and_Jacobian(const NonlinearSystem::Sol<scaled> & x)
{
  set_guess(x);
  return residual_and_Jacobian<scaled>();
}
} // namespace neml2