Predictor Corrector Euler integrator. More...

#include "../miluphpc.h"
#include "device_predictor_corrector_euler.cuh"
#include "device_explicit_euler.cuh"

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Classes
class	PredictorCorrectorEuler

Detailed Description

Predictor Corrector Euler integrator.

Predictor Corrector Euler integrator inheriting from the Miluphpc class.

Predictor corrector integrators generally consist out of one or multiple predictor steps and a corresponding correction. Since the accelerations needed for correction are determined using the predicted positions of the particles it may happen that particles are moving out of their current domain and do not belong anymore to the same process they belonged to before the prediction step. By the construction of the presented parallelization approach, this would require a subsequent reassigning of those particles. However, this includes the particle exchange between the MPI processes and consequently an inevitable resorting of all particles. Since the information need to be recombined for each particle in order to complete the integration step for the predictor-corrector scheme, the particles would have to be sent back and correctly ordered to align the original particle sorting. This is surely doable but most likely really inefficient in terms of performance.

The reason for the necessity of having the particles on the process they belong to is the correctness of the parallel tree. More precisely the correctness of the pseudo-particles and their COMs and masses, which is a key ingredient of the Barnes-Hut method for calculating the gravitational forces.

However, the SPH part is not relying on the correctness of the pseudo-particles and the neighbor search using the tree can be performed correctly as long as the pseudo-particle center-of-masses are within the correct cell regarding their location in the tree. Hence, by decoupling gravity it is possible to use the predictor-corrector scheme for SPH only and allow a temporarily corrupt tree in means of false pseudo-particles avoiding the necessity of assigning the particles to the correct process for the corrector step.

Though, for finding the correct interaction partners for each particle it is necessary to have an additional constraint on the chosen time step. Particles should not move farther than the half of the search radius used to find the particles to be exchanged.

Author: Michael Staneker

Bug:: no known bugs

Definition in file predictor_corrector_euler.h.

Classes

Detailed Description