Equation Systems¶

class EquationSystem

Base class representation of a PDE.

EquationSystem defines the API supported by all concrete implementations of PDEs for performing the following actions:

• Register computational fields

• Register computational algorithms for interior domain and boundary conditions

• Manage solve and update of the PDE for a given timestep

Subclassed by sierra::nalu::ContinuityEquationSystem, sierra::nalu::ContinuityFemEquationSystem, sierra::nalu::EnthalpyEquationSystem, sierra::nalu::HeatCondEquationSystem, sierra::nalu::KEpsilonEquationSystem, sierra::nalu::LowMachEquationSystem, sierra::nalu::LowMachFemEquationSystem, sierra::nalu::MassFractionEquationSystem, sierra::nalu::MeshDisplacementEquationSystem, sierra::nalu::MixtureFractionEquationSystem, sierra::nalu::MixtureFractionFemEquationSystem, sierra::nalu::MomentumEquationSystem, sierra::nalu::MomentumFemEquationSystem, sierra::nalu::ProjectedNodalGradientEquationSystem, sierra::nalu::RadiativeTransportEquationSystem, sierra::nalu::ShearStressTransportEquationSystem, sierra::nalu::SpecificDissipationRateEquationSystem, sierra::nalu::TurbDissipationEquationSystem, sierra::nalu::TurbKineticEnergyEquationSystem, sierra::nalu::VolumeOfFluidEquationSystem

Public Functions

virtual void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

virtual void pre_iter_work()

Perform setup tasks before entering the solve and update step.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();                //<<<< Pre-iteration setup
eqsys->solve_and_update();
eqsys->post_iter_work();
}
post_iter_work();


See

virtual void post_iter_work()

Perform setup tasks after he solve and update step.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();
eqsys->post_iter_work();                //<<<< Post-iteration actions
}
post_iter_work();


See

virtual void post_iter_work_dep()

Deprecated post iteration work logic.

Public Members

std::vector<AlgorithmDriver *> preIterAlgDriver_

List of tasks to be performed before each EquationSystem::solve_and_update.

std::vector<AlgorithmDriver *> postIterAlgDriver_

List of tasks to be performed after each EquationSystem::solve_and_update.

class LowMachEquationSystem : public sierra::nalu::EquationSystem

Low-Mach formulation of the Navier-Stokes Equations.

This class is a thin-wrapper around sierra::nalu::ContinuityEquationSystem and sierra::nalu::MomentumEquationSystem that orchestrates the interactions between the velocity and the pressure Possion solves in the LowMachEquationSystem::solve_and_update method.

Public Functions

virtual void pre_iter_work()

Perform setup tasks before entering the solve and update step.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();                //<<<< Pre-iteration setup
eqsys->solve_and_update();
eqsys->post_iter_work();
}
post_iter_work();


See

virtual void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class EnthalpyEquationSystem : public sierra::nalu::EquationSystem

Public Functions

void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

void post_iter_work_dep()

Deprecated post iteration work logic.

class TurbKineticEnergyEquationSystem : public sierra::nalu::EquationSystem

Public Functions

void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class ShearStressTransportEquationSystem : public sierra::nalu::EquationSystem

Public Functions

virtual void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class HeatCondEquationSystem : public sierra::nalu::EquationSystem

Public Functions

void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class MassFractionEquationSystem : public sierra::nalu::EquationSystem

Public Functions

void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class MixtureFractionEquationSystem : public sierra::nalu::EquationSystem

Public Functions

void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class MomentumEquationSystem : public sierra::nalu::EquationSystem

Representation of the Momentum conservation equations in 2-D and 3-D.

class ContinuityEquationSystem : public sierra::nalu::EquationSystem
class SpecificDissipationRateEquationSystem : public sierra::nalu::EquationSystem
class ProjectedNodalGradientEquationSystem : public sierra::nalu::EquationSystem

Public Functions

void solve_and_update()

Assemble the LHS and RHS and perform linear solve for prescribed number of iterations.

This method is invoked in EquationSystems::solve_and_update method as shown below

pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();             //<<<< Assemble and solve system
eqsys->post_iter_work();
}
post_iter_work();


See

class EquationSystems

A collection of Equations to be solved on a Realm.

EquationSystems holds a vector of EquationSystem instances representing the equations that are being solved in a given Realm and is responsible for the management of the solve and update of the various field quantities in a given timestep.

See

Public Functions

bool solve_and_update()

Solve and update the state of all variables for a given timestep.

This method is responsible for executing setup actions before calling solve, performing the actual solve, updating the solution, and performing post-solve actions after the solution has been updated. To provide sufficient granularity and control of this pre- and post- solve actions, the solve method uses the following series of steps:

// Perform tasks for this timestep before any Equation system is called
pre_iter_work();
// Iterate over all equation systems
for (auto eqsys: equationSystems_) {
eqsys->pre_iter_work();
eqsys->solve_and_update();
eqsys->post_iter_work();
}
// Perform tasks after all equation systems have updated
post_iter_work();


Tasks that require to be performed before any equation system is solved for needs to be registered to preIterAlgDriver_ on EquationSystems, similiary for post-solve tasks. And actions to be performed immediately before individual equation system solves need to be registered in EquationSystem::preIterAlgDriver_.

See
See

void pre_iter_work()

Perform necessary setup tasks that affect all EquationSystem instances at a given timestep.

See

void post_iter_work()

Perform necessary actions once all EquationSystem instances have been updated for the prescribed number of outer iterations at a given timestep.

See

Public Members

std::vector<AlgorithmDriver *> preIterAlgDriver_

A list of tasks to be performed before all EquationSystem::solve_and_update.

std::vector<AlgorithmDriver *> postIterAlgDriver_

A list of tasks to be performed after all EquationSystem::solve_and_update.