double AdvectionDiffusionSLE_AdvectiveTimestep( void* advectionDiffusionSLE ) {
AdvectionDiffusionSLE* self = (AdvectionDiffusionSLE*) advectionDiffusionSLE;
AdvDiffResidualForceTerm* residualForceTerm = self->advDiffResidualForceTerm;
FeVariable* velocityField = residualForceTerm->velocityField;
Node_LocalIndex nodeLocalCount = FeMesh_GetNodeLocalSize( self->phiField->feMesh );
Node_LocalIndex node_I;
Dimension_Index dim = self->dim;
Dimension_Index dim_I;
double timestep = HUGE_VAL;
XYZ velocity;
double minSeparation;
double minSeparationEachDim[3];
double* meshCoord;
Journal_DPrintf( self->debug, "In func: %s\n", __func__ );
FeVariable_GetMinimumSeparation( self->phiField, &minSeparation, minSeparationEachDim );
for( node_I = 0 ; node_I < nodeLocalCount ; node_I++ ){
if( self->phiField->feMesh == velocityField->feMesh){
FeVariable_GetValueAtNode( velocityField, node_I, velocity );
} else {
meshCoord = Mesh_GetVertex( self->phiField->feMesh, node_I );
FieldVariable_InterpolateValueAt( velocityField, meshCoord, velocity );
}
for ( dim_I = 0 ; dim_I < dim ; dim_I++ ) {
if( velocity[ dim_I ] == 0.0 )
continue;
timestep = MIN( timestep, fabs( minSeparationEachDim[ dim_I ]/velocity[ dim_I ] ) );
}
}
return self->courantFactor * timestep;
}
double AdvectionDiffusionSLE_DiffusiveTimestep( void* advectionDiffusionSLE ) {
AdvectionDiffusionSLE* self = (AdvectionDiffusionSLE*) advectionDiffusionSLE;
double minSeparation;
double minSeparationEachDim[3];
Journal_DPrintf( self->debug, "In func: %s\n", __func__ );
FeVariable_GetMinimumSeparation( self->phiField, &minSeparation, minSeparationEachDim );
/* This is quite a conservative estimate */
return self->courantFactor * minSeparation * minSeparation / self->maxDiffusivity;
}
double Dt( void* _context ) {
FiniteElementContext* context = (FiniteElementContext*) _context;
double dt;
FeVariable* velocityField = (FeVariable*) LiveComponentRegister_Get( context->CF->LCRegister, (Name)"VelocityField" );
double velMax;
double delta[3], minDelta;
velMax = FieldVariable_GetMaxGlobalFieldMagnitude( velocityField );
FeVariable_GetMinimumSeparation( velocityField, &minDelta, delta );
dt = 0.5 * minDelta / velMax;
return dt;
}
double SwarmAdvector_MaxDt( void* swarmAdvector ) {
SwarmAdvector* self = (SwarmAdvector*) swarmAdvector;
double velMax = 0;
double minSeparation = 0;
double minSeparationEachDim[3] = { 0, 0, 0 };
FeVariable* velFeVar = self->velocityField;
double localDt;
double globalDt;
velMax = FieldVariable_GetMaxGlobalFieldMagnitude( velFeVar );
FeVariable_GetMinimumSeparation( velFeVar, &minSeparation, minSeparationEachDim );
localDt = 0.5 * minSeparation / velMax;
(void)MPI_Allreduce( &localDt, &globalDt, 1, MPI_DOUBLE, MPI_MIN, MPI_COMM_WORLD );
return globalDt;
}
