CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

Multigrid: AMG GMG FMG

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   June 28, 1999, 02:22
Default Multigrid: AMG GMG FMG
J Roued
Posts: n/a

I have a simpel question about different multigrid approaches:

What is the difference between Algebraic Multigrid, Geometric Multigrid Fuld Multigrid



  Reply With Quote

Old   June 28, 1999, 08:12
Default Re: Multigrid: AMG GMG FMG
Kaare A Sorensen
Posts: n/a
Hi Jens,

AMG is an abstraction of traditional multigrid methods (GMG). In AMG you base your approach on the algebraic (hence the name) system Ax=b rather than the physical (PDE-) equations on a geometry (hence ...) where you have the notion of grids. In AMG instead of solving on coarser meshes, you are adding lines in your system of equations. The reason AMG is called a multigrid method even though 'grid' is undefined in its context is that it in some cases is equivalent to the traditional MG approach, and was probably motivated by it. The applicability of AMG seems to be somewhat restricted at the moment, in particular I've only seen it used on linear applications.

FMG is not directly related to the definitions above. Rather FMG is a way to generate a good initial guess for the selected MG procedure by obtaining less expensive solutions on coarser meshes (by f.ex. MG) and mapping the solution itself (not the correction) up to the finest grid.

Ha en god dag!

  Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
v4 & AMG warning msg more work Siemens 8 February 10, 2017 00:17
Quarter Burner mesh with periosic condition SamCanuck FLUENT 2 August 31, 2011 11:34
Divergence detected in AMG & FMG solver..... devesh.baghel FLUENT 1 January 17, 2011 02:58
AMG versus ICCG msrinath80 OpenFOAM Running, Solving & CFD 2 November 7, 2006 16:15
Multigrid applied to k-e models Paulo Zandonade Main CFD Forum 9 May 24, 1999 08:10

All times are GMT -4. The time now is 21:26.