Variable.h

// Copyright 2024, UChicago Argonne, LLC
// All Rights Reserved
// Software Name: NEML2 -- the New Engineering material Model Library, version 2
// By: Argonne National Laboratory
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#pragma once
 
#include "neml2/models/VariableBase.h"
 
namespace neml2
{
template <typename T>
class Variable : public VariableBase
{
public:
  Variable(VariableName name_in, Model * owner)
    : VariableBase(std::move(name_in), owner, T::const_base_sizes),
      _ref(nullptr)
  {
  }
 
  TensorType type() const override;

  // These methods mirror TensorBase
  bool defined() const override;
  TensorOptions options() const override;
  Dtype scalar_type() const override;
  Device device() const override;
 
  const TraceableTensorShape & dynamic_sizes() const override;
 
  std::unique_ptr<VariableBase> clone(const VariableName & name = {},
                                      Model * owner = nullptr) const override;
 
  void ref(VariableBase & var) override;
  const VariableBase * ref() const override { return _ref ? _ref->ref() : this; }
  VariableBase * ref() override { return _ref ? _ref->ref() : this; }
  const VariableBase * direct_ref() const override { return _ref; }
  VariableBase * direct_ref() override { return _ref; }
 
  bool owning() const override { return !_ref; }
 
  void zero(const TensorOptions & options) override;
 
  Tensor tensor() const override;
 
  void requires_grad_(bool req = true) override;
 
  void assign(const Tensor & val,
              [[maybe_unused]] std::optional<TracerPrivilege> key = std::nullopt) override;
 
  void operator=(const Tensor & val) override;

  const T & operator()() const { return owning() ? _value : (*_ref)(); }

  T operator-() const { return -operator()(); }
 
  void clear() override;
 
protected:
  Variable<T> * _ref;

  T _value;
};
} // namespace neml2