gradient.hpp

// Copyright (c) Sleipnir contributors
 
#pragma once
 
#include <utility>
 
#include <Eigen/SparseCore>
 
#include "sleipnir/autodiff/jacobian.hpp"
#include "sleipnir/autodiff/variable.hpp"
#include "sleipnir/autodiff/variable_matrix.hpp"
#include "sleipnir/util/concepts.hpp"
#include "sleipnir/util/symbol_exports.hpp"
 
namespace slp {
 
template <typename Scalar>
class Gradient {
 public:
  Gradient(Variable<Scalar> variable, Variable<Scalar> wrt)
      : m_jacobian{std::move(variable), std::move(wrt)} {}
 
  Gradient(Variable<Scalar> variable, SleipnirMatrixLike<Scalar> auto wrt)
      : m_jacobian{VariableMatrix{std::move(variable)}, std::move(wrt)} {}
 
  VariableMatrix<Scalar> get() const { return m_jacobian.get().T(); }
 
  const Eigen::SparseVector<Scalar>& value() {
    m_g = m_jacobian.value().transpose();
 
    return m_g;
  }
 
 private:
  Eigen::SparseVector<Scalar> m_g;
 
  Jacobian<Scalar> m_jacobian;
};
 
extern template class EXPORT_TEMPLATE_DECLARE(
    SLEIPNIR_DLLEXPORT) Gradient<double>;
 
}  // namespace slp