dg::MultistepTimeloop< ContainerType > Struct Template Reference

Integrate using a for loop and a fixed non-changeable time-step. More...

Inheritance diagram for dg::MultistepTimeloop< ContainerType >:

Public Types
using	container_type = ContainerType
using	value_type = dg::get_value_type<ContainerType>
Public Types inherited from dg::aTimeloop< ContainerType >
using	value_type = dg::get_value_type<ContainerType>
using	container_type = ContainerType

Public Member Functions
	MultistepTimeloop ()=default
	no allocation
	MultistepTimeloop (std::function< void(value_type &, ContainerType &)> step, value_type dt)
	Construct using a std::function.
template<class Stepper , class ODE >
	MultistepTimeloop (Stepper &&stepper, ODE &&ode, value_type t0, const ContainerType &u0, value_type dt)
	Initialize and bind the step function of a Multistep stepper.
template<class ... Params>
void	construct (Params &&...ps)
	Perfect forward parameters to one of the constructors.
virtual MultistepTimeloop *	clone () const
	Abstract copy method that returns a copy of *this on the heap.
Public Member Functions inherited from dg::aTimeloop< ContainerType >
void	integrate (value_type t0, const ContainerType &u0, value_type t1, ContainerType &u1)
	Integrate a differential equation between given bounds.
void	integrate (value_type &t0, const ContainerType &u0, value_type t1, ContainerType &u1, enum to mode)
	Build your own timeloop.
value_type	get_dt () const
	The current timestep.
virtual	~aTimeloop ()

Additional Inherited Members
Protected Member Functions inherited from dg::aTimeloop< ContainerType >
	aTimeloop ()
	empty
	aTimeloop (const aTimeloop &)
	empty
aTimeloop &	operator= (const aTimeloop &)
	return *this

Detailed Description

template<class ContainerType>
struct dg::MultistepTimeloop< ContainerType >

Integrate using a for loop and a fixed non-changeable time-step.

The implementation (of integrate) is equivalent to

dg::blas1::copy( u0, u1);
unsigned N = round((t1 - t0)/dt);
for( unsigned i=0; i<N; i++)
    step( t0, u1);

where dt is a given constant. t1 can only be matched exactly if the timestep evenly divides the given interval.

Note

the difference to dg::SinglestepTimeloop is the way the step function is called and the fact that dt cannot be changed

See also

AdaptiveTimeloop, SinglestepTimeloop

Template Parameters

ContainerType

Any class for which a specialization of TensorTraits exists and which fulfills the requirements of the there defined data and execution policies derived from AnyVectorTag and AnyPolicyTag. Among others dg::HVec (serial), dg::DVec (cuda / omp), dg::MHVec (mpi + serial) or dg::MDVec (mpi + cuda / omp) std::vector<dg::DVec> (vector of shared device vectors), std::array<double, 4> (array of 4 doubles) or std::map < std::string, dg::DVec> ( a map of named vectors) double (scalar) and other primitive types ... If there are several ContainerTypes in the argument list, then TensorTraits must exist for all of them

See also

See The dg dispatch system for a detailed explanation of our type dispatch system

Member Typedef Documentation

container_type

template<class ContainerType >

using dg::MultistepTimeloop< ContainerType >::container_type = ContainerType

value_type

template<class ContainerType >

using dg::MultistepTimeloop< ContainerType >::value_type = dg::get_value_type<ContainerType>

Constructor & Destructor Documentation

MultistepTimeloop() [1/3]

template<class ContainerType >

dg::MultistepTimeloop< ContainerType >::MultistepTimeloop ( )

default

no allocation

MultistepTimeloop() [2/3]

template<class ContainerType >

dg::MultistepTimeloop< ContainerType >::MultistepTimeloop ( std::function< void(value_type &, ContainerType &)> step, value_type dt )

inline

Construct using a std::function.

Parameters

step	Called in the timeloop as step( t0, u1) . Has to advance the ode in-place by dt
dt	The constant timestep. Can be set later with set_dt. Can be negative.

MultistepTimeloop() [3/3]

template<class ContainerType >

template<class Stepper , class ODE >

dg::MultistepTimeloop< ContainerType >::MultistepTimeloop ( Stepper && stepper, ODE && ode, value_type t0, const ContainerType & u0, value_type dt )

inline

Initialize and bind the step function of a Multistep stepper.

First call stepper.init(). Then construct a lambda function that calls the step function of stepper with given parameters and stores it internally in a std::function

Template Parameters

Stepper

possible steppers are for example dg::ExplicitMultistep, dg::ImplicitMultistep or dg::ImExMultistep

Parameters

stepper

If constructed in-place (rvalue), will be copied into the lambda. If an lvalue, then the lambda stores a reference

Attention

If stepper is an lvalue then you need to make sure that stepper remains valid to avoid a "dangling reference"

Template Parameters

ODE	The ExplicitRHS or tuple type that corresponds to what is inserted into the step member of the Stepper

Parameters

ode	rhs or tuple
t0	The initial time (forwarded to stepper.init( ode, t0, u0, dt) )
u0	The initial condition (forwarded to stepper.init( ode, t0, u0, dt) )
dt	The constant timestep. Can be negative. Cannot be changed as changing it would require to re-init the multistep stepper (which is hidden in the lambda). (forwarded to stepper.init( ode, t0, u0, dt) )

Member Function Documentation

clone()

template<class ContainerType >

virtual MultistepTimeloop * dg::MultistepTimeloop< ContainerType >::clone ( ) const

inlinevirtual

Abstract copy method that returns a copy of *this on the heap.

Returns

a copy of *this on the heap

See also

dg::ClonePtr

Implements dg::aTimeloop< ContainerType >.

construct()

template<class ContainerType >

template<class ... Params>

void dg::MultistepTimeloop< ContainerType >::construct ( Params &&... ps )

inline

Perfect forward parameters to one of the constructors.

Template Parameters

Params

deduced by the compiler

Parameters

ps	parameters forwarded to constructors

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The documentation for this struct was generated from the following file:

• multistep.h