Fem3DElementTetrahedron.h

// This file is a part of the OpenSurgSim project.
// Copyright 2013, SimQuest Solutions Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SURGSIM_PHYSICS_FEM3DELEMENTTETRAHEDRON_H
#define SURGSIM_PHYSICS_FEM3DELEMENTTETRAHEDRON_H

#include <array>

#include "SurgSim/Math/Matrix.h"
#include "SurgSim/Math/Vector.h"
#include "SurgSim/Physics/Fem.h"
#include "SurgSim/Physics/FemElement.h"

namespace SurgSim
{

namespace Physics
{
SURGSIM_STATIC_REGISTRATION(Fem3DElementTetrahedron);

class Fem3DElementTetrahedron : public FemElement
{
public:
    Fem3DElementTetrahedron();

    explicit Fem3DElementTetrahedron(std::array<size_t, 4> nodeIds);

    explicit Fem3DElementTetrahedron(std::shared_ptr<FemElementStructs::FemElementParameter> elementData);

    SURGSIM_CLASSNAME(SurgSim::Physics::Fem3DElementTetrahedron)

    void initialize(const SurgSim::Math::OdeState& state) override;

    double getVolume(const SurgSim::Math::OdeState& state) const override;

    SurgSim::Math::Vector computeCartesianCoordinate(const SurgSim::Math::OdeState& state,
            const SurgSim::Math::Vector& naturalCoordinate) const override;

    SurgSim::Math::Vector computeNaturalCoordinate(const SurgSim::Math::OdeState& state,
            const SurgSim::Math::Vector& cartesianCoordinate) const override;

protected:
    void initializeMembers();

    void doUpdateFMDK(const Math::OdeState& state, int options) override;

    void computeShapeFunctions(const SurgSim::Math::OdeState& state,
                               double* volume,
                               std::array<double, 4>* ai,
                               std::array<double, 4>* bi,
                               std::array<double, 4>* ci,
                               std::array<double, 4>* di) const;

    void computeStiffness(const SurgSim::Math::OdeState& state,
                          SurgSim::Math::Matrix* k);

    void computeMass(const SurgSim::Math::OdeState& state,
                     SurgSim::Math::Matrix* m);

    Eigen::Matrix<double, 12, 1> m_x0;

};

namespace Tetrahedron {
    template <class Vector, class SubVector>
    void getSubVector(const Vector& vector, const std::vector<size_t>& blockIds, SubVector* subVector)
    {
        static const int blockSize = 3;
        subVector->segment(blockSize * 0, blockSize) = vector.segment(blockSize * blockIds[0], blockSize);
        subVector->segment(blockSize * 1, blockSize) = vector.segment(blockSize * blockIds[1], blockSize);
        subVector->segment(blockSize * 2, blockSize) = vector.segment(blockSize * blockIds[2], blockSize);
        subVector->segment(blockSize * 3, blockSize) = vector.segment(blockSize * blockIds[3], blockSize);
    }
}

} // namespace Physics

} // namespace SurgSim

#endif // SURGSIM_PHYSICS_FEM3DELEMENTTETRAHEDRON_H