Contains functions to solve Poisson's equation for self-gravity in 3D using multigrid. More...

Classes
struct	MGrid
	Holds RHS, potential, and information about grid size for a given level in the multi-grid hierarchy. More...
Functions
void	multig_3d (MGrid *pMG)
	Functions needed for the multigrid solver in 3D.
void	Jacobi (MGrid *pMG)
	Jacobi iterations.
void	Restriction_3d (MGrid pMG_fine, MGrid pMG_coarse)
	Averages fine grid solution onto coarse.
void	Prolongation_3d (MGrid pMG_coarse, MGrid pMG_fine)
	Linear interpolation of coarse grid onto fine.
void	set_mg_bvals (MGrid *pMG)
	Sets BC for Jacobi iterates for MPI parallel jobs.
void	swap_mg_ix1 (MGrid pMG, int cnt, int swap_flag, MPI_Request prq)
	MPI_SWAP of boundary conditions, Inner x1 boundary.
void	swap_mg_ox1 (MGrid pMG, int cnt, int swap_flag, MPI_Request prq)
	MPI_SWAP of boundary conditions, Outer x1 boundary.
void	swap_mg_ix2 (MGrid pMG, int cnt, int swap_flag, MPI_Request prq)
	MPI_SWAP of boundary conditions, Inner x2 boundary.
void	swap_mg_ox2 (MGrid pMG, int cnt, int swap_flag, MPI_Request prq)
	MPI_SWAP of boundary conditions, Outer x2 boundary.
void	swap_mg_ix3 (MGrid pMG, int cnt, int swap_flag, MPI_Request prq)
	MPI_SWAP of boundary conditions, Inner x3 boundary.
void	swap_mg_ox3 (MGrid pMG, int cnt, int swap_flag, MPI_Request prq)
	MPI_SWAP of boundary conditions, Outer x3 boundary.
void	selfg_multig_1d (DomainS *pD)
	1-D multigrid gravity
void	selfg_multig_2d (DomainS *pD)
	2-D multigrid gravity
void	selfg_multig_3d (DomainS *pD)
	Do not use with periodic BCs, uses multipole expansion to compute potential at boundary.
void	selfg_multig_3d_init (MeshS *pM)
	Initialize send/receive buffers needed to swap iterates during Jacobi iterations.
Variables
static double *	send_buf = NULL
static double *	recv_buf = NULL
Real ***	error

Detailed Description

Contains functions to solve Poisson's equation for self-gravity in 3D using multigrid.

These functions work for non-periodic domains. A low-order multipole expansion is used to compute the potential on the boundaries.

HISTORY:

june-2007 - 2D and 3D solvers written by Irene Balmes
july-2007 - routines incorporated into Athena by JMS and IB

CONTAINS PUBLIC FUNCTIONS:

selfg_by_multig_2d() - 2D Poisson solver using multigrid
selfg_by_multig_3d() - 3D Poisson solver using multigrid
selfg_by_multig_3d_init() - Initializes send/receive buffers for MPI

Definition in file selfg_multigrid.c.

Function Documentation

void Jacobi ( MGrid * pMG )

Jacobi iterations.

Do not use with periodic BCs, uses multipole expansion to compute potential at boundary

Definition at line 380 of file selfg_multigrid.c.

References MGrid::dx1, MGrid::dx2, MGrid::dx3, error, MGrid::ie, MGrid::is, MGrid::je, MGrid::js, MGrid::ke, MGrid::ks, n, MGrid::Nx3, MGrid::Phi, MGrid::rhs, and set_mg_bvals().

Referenced by multig_3d().

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void multig_3d ( MGrid * pMG )

Functions needed for the multigrid solver in 3D.

Definition at line 298 of file selfg_multigrid.c.

References ath_error(), calloc_3d_array(), MGrid::dx1, MGrid::dx2, MGrid::dx3, free_3d_array(), MGrid::ie, MGrid::is, Jacobi(), MGrid::je, MGrid::js, MGrid::ke, MGrid::ks, MGrid::lx1_id, MGrid::lx2_id, MGrid::lx3_id, MGrid::Nx1, MGrid::Nx2, MGrid::Nx3, MGrid::Phi, Prolongation_3d(), Restriction_3d(), MGrid::rhs, MGrid::rx1_id, MGrid::rx2_id, MGrid::rx3_id, and set_mg_bvals().

Referenced by selfg_multig_3d().

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void Prolongation_3d	(	MGrid *	pMG_coarse,
		MGrid *	pMG_fine
	)

Linear interpolation of coarse grid onto fine.

Definition at line 496 of file selfg_multigrid.c.

References MGrid::ie, MGrid::is, MGrid::je, MGrid::js, MGrid::ke, MGrid::ks, and MGrid::Phi.

Referenced by multig_3d().

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void Restriction_3d	(	MGrid *	pMG_fine,
		MGrid *	pMG_coarse
	)

Averages fine grid solution onto coarse.

Definition at line 449 of file selfg_multigrid.c.

References MGrid::dx1, MGrid::dx2, MGrid::dx3, error, MGrid::ie, MGrid::is, MGrid::je, MGrid::js, MGrid::ke, MGrid::ks, MGrid::Phi, and MGrid::rhs.

Referenced by multig_3d().

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void selfg_multig_1d ( DomainS * pD )

1-D multigrid gravity

Definition at line 87 of file selfg_multigrid.c.

References ath_error().

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void selfg_multig_2d ( DomainS * pD )

2-D multigrid gravity

Definition at line 98 of file selfg_multigrid.c.

References ath_error().

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void selfg_multig_3d ( DomainS * pD )

Do not use with periodic BCs, uses multipole expansion to compute potential at boundary.

Definition at line 110 of file selfg_multigrid.c.

References ath_error(), calloc_3d_array(), cc_pos(), ConsS::d, MGrid::dx1, GridS::dx1, MGrid::dx2, GridS::dx2, MGrid::dx3, GridS::dx3, four_pi_G, free_3d_array(), DomainS::Grid, MGrid::ie, GridS::ie, MGrid::is, GridS::is, MGrid::je, GridS::je, MGrid::js, GridS::js, MGrid::ke, GridS::ke, MGrid::ks, GridS::ks, MGrid::lx1_id, GridS::lx1_id, MGrid::lx2_id, GridS::lx2_id, MGrid::lx3_id, GridS::lx3_id, multig_3d(), GridS::Nx, MGrid::Nx1, MGrid::Nx2, MGrid::Nx3, MGrid::Phi, GridS::Phi, GridS::Phi_old, rad, MGrid::rhs, MGrid::rx1_id, GridS::rx1_id, MGrid::rx2_id, GridS::rx2_id, MGrid::rx3_id, GridS::rx3_id, set_mg_bvals(), and GridS::U.

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void selfg_multig_3d_init ( MeshS * pM )

Initialize send/receive buffers needed to swap iterates during Jacobi iterations.

Definition at line 1043 of file selfg_multigrid.c.

References ath_error(), calloc_3d_array(), MeshS::Domain, MeshS::DomainsPerLevel, error, DomainS::Grid, MeshS::NLevels, GridS::Nx, par_geti(), recv_buf, and send_buf.

Referenced by selfg_init().

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void set_mg_bvals ( MGrid * pMG )

Sets BC for Jacobi iterates for MPI parallel jobs.

With self-gravity using multigrid, the boundary conditions at the edge of the Domain are held fixed. So only ghostzones associated with internal boundaries between MPI grids need to be passed.

This routine is largely a copy of set_bvals(). Order for updating boundary conditions must always be x1-x2-x3 in order to fill the corner cells properly

Definition at line 548 of file selfg_multigrid.c.

References ath_error(), MGrid::lx1_id, MGrid::lx2_id, MGrid::lx3_id, MGrid::Nx1, MGrid::Nx2, MGrid::Nx3, recv_buf, MGrid::rx1_id, MGrid::rx2_id, MGrid::rx3_id, swap_mg_ix1(), swap_mg_ix2(), swap_mg_ix3(), swap_mg_ox1(), swap_mg_ox2(), and swap_mg_ox3().