Class CVodeIntegrator

Class CVodeIntegrator#

Nested Relationships#

Nested Types#

Inheritance Relationships#

Base Type#

Class Documentation#

class CVodeIntegrator : public Karana::Math::Integrator#

The multistep CVode integrator from the SUNDIALS suite.

Public Types

enum class NLSOLVER#

the nonlinear solver type to use

Values:

enumerator FIXEDPOINT#
enumerator NEWTON#
enum class METHOD#

the solver type to use

Values:

enumerator ADAMS#
enumerator BDF#

Public Functions

CVodeIntegrator(size_t nstates, DerivativeFunction f, const IntegratorType &integrator_type, const IntegratorOptions *options = nullptr)#

Constructor.

Parameters:

  • nstates – The number of states to integrate.

  • f – The derivative function to calculate the derivative of the states.

  • integrator_type – The type of cvode integrator to use.

  • options – The integrator options.

~CVodeIntegrator()#
virtual std::string_view typeString() const override#

Return the integrator type as a string.

Returns:

the integrator type

virtual void hardReset(size_t nstates) override#

Reset the state size.

Parameters:

nstates – the new state size

virtual void softReset(const Ktime &new_t, const Vec &new_x) override#

Reset the cached time and state and to the new values going forward.

Parameters:

  • new_t – the new time

  • new_x – the new state

virtual Ktime advanceTo(const Ktime &t_end) override#

Method to advance the sytem state to a specified time.

Parameters:

to_t – the desired end time

Returns:

the actual end time

virtual void updateJacobian(const Mat &mat) override#

Update the stored Jacobian matrix with the provided one.

This is currently an experimental feature - and not all integrators support the use of Jacobians.

Parameters:

mat – the new Jacobian matrix

virtual std::unique_ptr<Integrator::IntegratorOptions> getOptions() override#

Get the options associated with the integrator.

Returns:

The options associated with the integrator.

virtual IntegratorType getIntegratorType() const override#

Get the IntegratorType for this integrator.

Returns:

The IntegratorType for this integrator.

Vec getErrorContributions() const#

Get the error contributions of the state components.

This is helpful for identifying problematic state components

Returns:

The error contributions.

int getCurrentOrder() const#

Return the current order of the integrator.

Returns:

The integrator order

double getLastStepSize() const#

Return the last step size used.

Returns:

The last step size

Protected Attributes

SUNContext _sunctx = nullptr#

Sundials context object.

N_Vector _y = nullptr#

The current integrator state.

SUNMatrix _a_mat = nullptr#

Matrix used in the linear solver.

Mat _jacobian_buffer#

buffer for the Jacobian matrix

SUNLinearSolver _ls = nullptr#

Linear solver.

SUNNonlinearSolver _nls = nullptr#

nonLinear solver

void *_cvode_mem#

Memory used by the cvode integrator.

Vec _dx#

The derivative of the states.

IntegratorType _integrator_type#

The integrator type.

Protected Static Functions

static int _cvode_f(realtype t, N_Vector y, N_Vector ydot, void *user_data)#

Calles the derivative function on the provided integrator state, and puts the derivative of the state into ydot.

Parameters:

  • t – The time to use when calculating the derivative.

  • y – The current integrator state.

  • ydot – The vector that will get populated with the derivative of the state.

  • user_data – Data used to by the deriative function.

Returns:

An error code indicating if the call was successful or not.

static int _cvode_jacobian(realtype t, N_Vector y, N_Vector fy, SUNMatrix J, void *user_data, N_Vector tmp1, N_Vector tmp2, N_Vector tmp3)#

Calculate the jacobian for the nonlinear solver.

type CVLsJacFn. Invoked by the integrator to get the Jacobian matrix (experimental)

Parameters:

  • t – The time to calculate the jacobian at.

  • y – The state to calculate the jacobian at.

  • fy – Unused.

  • J – The matrix that willl be populated with the jacobian.

  • user_data – Any extra data needed to calculate the jacobian.

  • tmp1 – Unused.

  • tmp2 – Unused.

  • tmp3 – Unused.

Returns:

An error code indicated success or failure of the call.

struct IntegratorOptions : public Karana::Math::Integrator::IntegratorOptions#

Struct with options for this integrator

Public Functions

IntegratorOptions() = default#
IntegratorOptions(const IntegratorOptions &p)#

Copy constructor.

Parameters:

p – The IntegratorOptions to copy values from.

IntegratorOptions &operator=(const IntegratorOptions &p)#

Assignment operator.

Parameters:

p – The IntegratorOptions to copy values from.

Returns:

A reference to the newly assigned IntegratorOptions.

virtual ~IntegratorOptions()#

Public Members

double rtol = 1e-4#

The desired relative tolerance used to control the integrator error.

double atol = 1e-8#

The desired absolute tolerance used to control the integrator error.

Vec atol_vec#

The desired absolute tolerance vector used to control the integrator error. This can be used rather than a scalar tolerance to set different values for different states.

long max_num_steps = 1e6#

The maximum number of steps the solver can take before throwing a too much work error.

unsigned int anderson_accel = 0#

Anderson acceleration used with the FixedPoint solver.

NLSOLVER nlsolver = NLSOLVER::FIXEDPOINT#

The Nonlinear solver type to use.

METHOD method = METHOD::ADAMS#

The solver method to use.

bool use_jacobian = false#

set to true to have the integrator use Jacobians (experimental)

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