neo_hooke.h

#pragma once

#include <funcy/examples/volumetric_penalty_functions.h>
#include <funcy/funcy.h>

namespace funcy
{
    template < linalg::Matrix M, int n = linalg::dim< M >() >
    auto incompressible_neo_hooke( double c, const M& F )
    {
        using namespace linalg;
        auto S = strain_tensor( F );
        auto x = i1( S );
        return finalize( c * ( x - n ) );
    }

    template < linalg::Matrix M, int n = linalg::dim< M >() >
    auto modified_incompressible_neo_hooke( double c, const M& F )
    {
        using namespace linalg;
        auto S = LeftCauchyGreenStrainTensor( F );
        return finalize( c * ( mi1< decltype( S ), n >( S ) - n ) );
    }

    template < class InflationPenalty, class CompressionPenalty, linalg::Matrix M,
               int n = linalg::dim< M >() >
    auto compressible_neo_hooke( double c, double d0, double d1, const M& F )
    {
        using namespace linalg;
        return finalize( c * ( i1( strain_tensor( F ) ) - n ) +
                         volumetric_penalty< InflationPenalty, CompressionPenalty >( d0, d1, F ) );
    }

    template < class InflationPenalty, class CompressionPenalty, linalg::Matrix M,
               int n = linalg::dim< M >() >
    auto modified_compressible_neo_hooke( double c, double d0, double d1, const M& F )
    {
        using namespace linalg;
        auto S = LeftCauchyGreenStrainTensor< M >( F );
        return finalize( c * ( mi1< decltype( S ), n >( S ) - n ) +
                         volumetric_penalty< InflationPenalty, CompressionPenalty >( d0, d1, F ) );
    }
} // namespace funcy