BarrierPotential¶

class BarrierPotential : public ipc::NormalPotential;¶

The barrier collision potential.

Public Functions¶

explicit BarrierPotential(
    const double dhat, const bool use_physical_barrier = false);¶

Construct a barrier potential.

Parameters:¶

const double dhat¶

The activation distance of the barrier.

const bool use_physical_barrier = false¶

Whether to use the physical barrier.

BarrierPotential(const std::shared_ptr<Barrier> barrier,
    const double dhat, const bool use_physical_barrier = false);¶

Construct a barrier potential.

Parameters:¶

const std::shared_ptr<Barrier> barrier¶

The barrier function.

const double dhat¶

The activation distance of the barrier.

const bool use_physical_barrier = false¶

Whether to use the physical barrier.

inline double dhat() const;¶

Get the activation distance of the barrier.

inline void set_dhat(const double dhat);¶

Set the activation distance of the barrier.

Parameters:¶

const double dhat¶

The activation distance of the barrier.

inline const Barrier& barrier() const;¶

Get the barrier function used to compute the potential.

inline void set_barrier(const std::shared_ptr<Barrier> barrier);¶

Set the barrier function used to compute the potential.

Parameters:¶

const std::shared_ptr<Barrier> barrier¶

The barrier function used to compute the potential.

virtual double force_magnitude(const double distance_squared,
    const double dmin,
    const double barrier_stiffness) const override;¶

Compute the force magnitude for a collision.

Parameters:¶

const double distance_squared¶

The squared distance between elements.

const double dmin¶

The minimum distance offset to the barrier.

const double barrier_stiffness¶

The barrier stiffness.

Returns:¶

The force magnitude.

virtual VectorMax12d force_magnitude_gradient(
    const double distance_squared,
    Eigen::ConstRef<VectorMax12d> distance_squared_gradient,
    const double dmin,
    const double barrier_stiffness) const override;¶

Compute the gradient of the force magnitude for a collision.

Parameters:¶

const double distance_squared¶

The squared distance between elements.

Eigen::ConstRef<VectorMax12d> distance_squared_gradient¶

The gradient of the squared distance.

const double dmin¶

The minimum distance offset to the barrier.

const double barrier_stiffness¶

The stiffness of the barrier.

Returns:¶

The gradient of the force.

inline bool use_physical_barrier() const;¶

Get whether to use the physical barrier.

Note

When using the convergent formulation we want the barrier to have units of Pa⋅m, so κ gets units of Pa and the barrier function should have units of m. See notebooks/physical_barrier.ipynb for more details.

inline void set_use_physical_barrier(bool use_physical_barrier);¶

Set use physical barrier flag.

Note

When using the convergent formulation we want the barrier to have units of Pa⋅m, so κ gets units of Pa and the barrier function should have units of m. See notebooks/physical_barrier.ipynb for more details.

Parameters:¶

bool use_physical_barrier¶

Whether to use the physical barrier.

VectorMax12d gradient(const NormalCollision& collision,
    Eigen::ConstRef<VectorMax12d> positions) const override;¶

Compute the gradient of the potential for a single collision.

Parameters:¶

const NormalCollision &collision¶

The collision.

Eigen::ConstRef<VectorMax12d> positions¶

The collision stencil’s positions.

Returns:¶

The gradient of the potential.

virtual double gradient(
    const double distance_squared, const double dmin = 0) const
    = 0;¶

Compute the gradient of the unmollified distance-based potential for a collision.

Parameters:¶

const double distance_squared¶

The distance (squared) between the two objects.

const double dmin = 0¶

The minimum distance (unsquared) between the two objects.

Returns:¶

The gradient of the unmollified distance-based potential.

MatrixMax12d hessian(const NormalCollision& collision,
    Eigen::ConstRef<VectorMax12d> positions,
    const PSDProjectionMethod project_hessian_to_psd
    = PSDProjectionMethod::NONE) const override;¶

Compute the hessian of the potential for a single collision.

Parameters:¶

const NormalCollision &collision¶

The collision.

Eigen::ConstRef<VectorMax12d> positions¶

The collision stencil’s positions.

const PSDProjectionMethod project_hessian_to_psd = PSDProjectionMethod::NONE¶

Whether to project the hessian to the positive semi-definite cone.

Returns:¶

The hessian of the potential.

virtual double hessian(
    const double distance_squared, const double dmin = 0) const
    = 0;¶

Compute the hessian of the unmollified distance-based potential for a collision.

Parameters:¶

const double distance_squared¶

The distance (squared) between the two objects.

const double dmin = 0¶

The minimum distance (unsquared) between the two objects.

Returns:¶

The hessian of the unmollified distance-based potential.

Protected Functions¶

virtual double operator()(const double distance_squared,
    const double dmin = 0) const override;¶

Compute the barrier potential for a collision.

Parameters:¶

const double distance_squared¶

The distance (squared) between the two objects.

const double dmin = 0¶

The minimum distance (unsquared) between the two objects.

Returns:¶

The barrier potential.

virtual double gradient(const double distance_squared,
    const double dmin = 0) const override;

Compute the gradient of the barrier potential for a collision.

Parameters:¶

const double distance_squared¶

The distance (squared) between the two objects.

const double dmin = 0¶

The minimum distance (unsquared) between the two objects.

Returns:¶

The gradient of the barrier potential.

virtual double hessian(const double distance_squared,
    const double dmin = 0) const override;

Compute the hessian of the barrier potential for a collision.

Parameters:¶

const double distance_squared¶

The distance (squared) between the two objects.

const double dmin = 0¶

The minimum distance (unsquared) between the two objects.

Returns:¶

The hessian of the barrier potential.

Protected Attributes¶

std::shared_ptr<Barrier> m_barrier
    = std::make_shared<ClampedLogBarrier>();¶

The barrier function used to compute the potential.

double m_dhat;¶

The activation distance of the barrier.

bool m_use_physical_barrier = false;¶

Whether to use the physical barrier.

Note

When using the convergent formulation we want the barrier to have units of Pa⋅m, so κ gets units of Pa and the barrier function should have units of m. See notebooks/physical_barrier.ipynb for more details.

Private Types¶

using Super = NormalPotential;¶