PetscSetInitialGuessROM.cpp File Reference

Compute an initial guess for implicit solves using a reduced-order model. More...

#include <simulation_object.h>
#include <petscinterface.h>
#include <librom_interface.h>

Go to the source code of this file.

Functions
PetscErrorCode	PetscSetInitialGuessROM (SNES snes, Vec X, void *ctxt)

Detailed Description

Compute an initial guess for implicit solves using a reduced-order model.

Author

Debojyoti Ghosh

Definition in file PetscSetInitialGuessROM.cpp.

Function Documentation

PetscErrorCode PetscSetInitialGuessROM	(	SNES	snes,
		Vec	X,
		void *	ctxt
	)

Compute the initial guess for a nonlinear solve using a trained libROM reduced-order model.

Parameters

snes	Nonlinear solver object (see PETSc SNES)
X	Initial guess vector
ctxt	Application context

Definition at line 18 of file PetscSetInitialGuessROM.cpp.

{
  PETScContext* context = (PETScContext*) ctxt;
  SimulationObject* sim = (SimulationObject*) context->simobj;
  int nsims = context->nsims;

  PetscFunctionBegin;

  double stage_time = context->t_start;
  if (context->stage_times.size() > (context->stage_index+1)) {
    stage_time += context->stage_times[context->stage_index+1] * context->dt;
  } else {
    stage_time += context->dt;
  }
        
  ((libROMInterface*)context->rom_interface)->predict(sim, stage_time);
  if (!context->rank) {
    printf(  "libROM: Predicted ROM intial guess (time %1.4e), wallclock time: %f.\n", 
             stage_time, ((libROMInterface*)context->rom_interface)->predictWallclockTime() );
  }

  for (int ns = 0; ns < nsims; ns++) {
    TransferVecToPETSc(sim[ns].solver.u,X,context,ns,context->offsets[ns]);
  }


  PetscFunctionReturn(0);
}