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From: Ataollah Mesgarnejad <amesga1@ti...>  20130509 21:19:27

On May 9, 2013, at 4:00 PM, Dmitry Karpeev <karpeev@...> wrote: > GAMG is primarily an algebraic multigrid preconditioner. > The geometric part is somewhat weaker and isn't the primary purpose of GAMG, > so I would recommend using pc_gamg_type agg for plain aggregation. > OK that's clear know, I was asking about the low level mesh implementation because I thought the geometric part will need to know something about the coordinates and what not. > For good performance with elasticity it is important to use smoothed aggregation, > for example, pc_gamg_agg_nsmooths 1 > but for that to be effective, it is critical to supply a "nearnullspace"  basically, > the nullspace of the Neumann operator. It is the rigid body modes in the case of elasticity. > If you are able to specify the block size of the matrix, GAMG will try to guess the correct > nearnullspace for you. In particular bs=3 will cause GAMG to construct the rigid body modes > from the coordinates set with PCSetCoordinates. > > Now, libMesh doesn't have an API for setting the matrix block size (as far as I know). > You can hack a bit: extract the PETSc objects and do it yourself, but a more natural way is > to compute your own rigid body modes in a callback attached to NonlinearSolver::nearnullspace or NonlinearSolver::nearnullspace_object. A nearnullspace is simply an array of NumericVector that > contains a basis for the nearnullspace. libMesh will orthonormalize it for you (PETSc requires > that). > Crystal clear. I'll get to it. Best, Ata > Hope this helps. > Dmitry. > > > On Thu, May 9, 2013 at 11:08 AM, Cody Permann <codypermann@...> wrote: > On Thu, May 9, 2013 at 9:18 AM, Ataollah Mesgarnejad <amesga1@... > > wrote: > > > > > Cody, > > > > On May 9, 2013, at 9:29 AM, Cody Permann <codypermann@...> wrote: > > > > > > > > > > On Thu, May 9, 2013 at 8:07 AM, Ataollah Mesgarnejad < > > amesga1@...> wrote: > > > >> Dear all, > >> > >> I was wondering if anyone has any experience using gamg with libMesh (I'm > >> particularly interested in elasticity)? > >> > >> > > It certainly works, however in my very limited experiecne, it's slightly > > more tricky to use than Hypre as we've found that it requires a few more > > options. Gamg is very flexible and part of PETSc so it ties in nicely. > > > > > > > > That's wonderful. Do I need to add anything in the code itself like block > > size or ..? Or do you mean the command line options for gamg? > > > > Just the command line options. If you have specific questions, the petsc > user list is a great place to ask. > > Cody > > > > > My main question would be if the geometric part of gamg would work with > >> the underlying mesh structure in libMesh? > >> > > > > I'm not sure if I'm missing something with this question. I don't see why > > this preconditioner would care about the mesh structure, it's abstracted > > well above that level. From libMesh's perspective, it's just another > > preconditioner. > > > > > > OK. I'm not very familiar with low level structure in libMesh so I wasn't > > sure. > > > > Thanks, > > Ata > > > > > > Cody > > > > > >> > >> I would appreciate any comments/recommendations, > >> Ata > >> > >>  > >> Learn Graph Databases  Download FREE O'Reilly Book > >> "Graph Databases" is the definitive new guide to graph databases and > >> their applications. This 200page book is written by three acclaimed > >> leaders in the field. The early access version is available now. > >> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > >> _______________________________________________ > >> Libmeshusers mailing list > >> Libmeshusers@... > >> https://lists.sourceforge.net/lists/listinfo/libmeshusers > >> > > > > > > >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers > > > > 
From: Dmitry Karpeev <karpeev@mc...>  20130509 21:01:33

GAMG is primarily an algebraic multigrid preconditioner. The geometric part is somewhat weaker and isn't the primary purpose of GAMG, so I would recommend using pc_gamg_type agg for plain aggregation. For good performance with elasticity it is important to use smoothed aggregation, for example, pc_gamg_agg_nsmooths 1 but for that to be effective, it is critical to supply a "nearnullspace"  basically, the nullspace of the Neumann operator. It is the rigid body modes in the case of elasticity. If you are able to specify the block size of the matrix, GAMG will try to guess the correct nearnullspace for you. In particular bs=3 will cause GAMG to construct the rigid body modes from the coordinates set with PCSetCoordinates. Now, libMesh doesn't have an API for setting the matrix block size (as far as I know). You can hack a bit: extract the PETSc objects and do it yourself, but a more natural way is to compute your own rigid body modes in a callback attached to NonlinearSolver::nearnullspace or NonlinearSolver::nearnullspace_object. A nearnullspace is simply an array of NumericVector that contains a basis for the nearnullspace. libMesh will orthonormalize it for you (PETSc requires that). Hope this helps. Dmitry. On Thu, May 9, 2013 at 11:08 AM, Cody Permann <codypermann@...> wrote: > On Thu, May 9, 2013 at 9:18 AM, Ataollah Mesgarnejad < > amesga1@... > > wrote: > > > > > Cody, > > > > On May 9, 2013, at 9:29 AM, Cody Permann <codypermann@...> wrote: > > > > > > > > > > On Thu, May 9, 2013 at 8:07 AM, Ataollah Mesgarnejad < > > amesga1@...> wrote: > > > >> Dear all, > >> > >> I was wondering if anyone has any experience using gamg with libMesh > (I'm > >> particularly interested in elasticity)? > >> > >> > > It certainly works, however in my very limited experiecne, it's slightly > > more tricky to use than Hypre as we've found that it requires a few more > > options. Gamg is very flexible and part of PETSc so it ties in nicely. > > > > > > > > That's wonderful. Do I need to add anything in the code itself like block > > size or ..? Or do you mean the command line options for gamg? > > > > Just the command line options. If you have specific questions, the petsc > user list is a great place to ask. > > Cody > > > > > My main question would be if the geometric part of gamg would work with > >> the underlying mesh structure in libMesh? > >> > > > > I'm not sure if I'm missing something with this question. I don't see > why > > this preconditioner would care about the mesh structure, it's abstracted > > well above that level. From libMesh's perspective, it's just another > > preconditioner. > > > > > > OK. I'm not very familiar with low level structure in libMesh so I wasn't > > sure. > > > > Thanks, > > Ata > > > > > > Cody > > > > > >> > >> I would appreciate any comments/recommendations, > >> Ata > >> > >> >  > >> Learn Graph Databases  Download FREE O'Reilly Book > >> "Graph Databases" is the definitive new guide to graph databases and > >> their applications. This 200page book is written by three acclaimed > >> leaders in the field. The early access version is available now. > >> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > >> _______________________________________________ > >> Libmeshusers mailing list > >> Libmeshusers@... > >> https://lists.sourceforge.net/lists/listinfo/libmeshusers > >> > > > > > > > >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers > 
From: David Knezevic <dknezevic@se...>  20130509 20:26:51

On 05/09/2013 04:21 PM, Peter Zajac wrote: > > On Thu, May 9, 2013 at 11:29 AM, David Knezevic > <dknezevic@... <mailto:dknezevic@...>> wrote: > > On 05/09/2013 02:22 PM, PETER ZAJAC wrote: > > David, > > I was worried about the volume element for integration. If I > use explicit transformations of coordinates to spherical how > would I make sure that the volume element for integration > changes accordingly. > > > Cartesian > spherical is just a change of coordinates, so if you > take that into account properly in the weak form then everything > is fine. In particular, you need to account for: >  the change of measure, which gives an extra r^2 * \sin(\phi) > factor, if memory serves >  the change of variables in the gradient terms > > It would be nice to automate this so that it is automatically > included in libMesh's JxW and dphi, which is what Paul was > referring to. But the easiest thing for you in the short term > would be to just explicitly deal with the change of variables > yourself. > > > Great. Thank you. This will work. P.S. You'll also need to impose periodic boundary conditions in the azimuthal direction. 
From: Peter Zajac <peterzajac1@gm...>  20130509 20:21:27

On Thu, May 9, 2013 at 11:29 AM, David Knezevic <dknezevic@...>wrote: > On 05/09/2013 02:22 PM, PETER ZAJAC wrote: > >> David, >> >> I was worried about the volume element for integration. If I use >> explicit transformations of coordinates to spherical how would I make sure >> that the volume element for integration changes accordingly. >> > > Cartesian > spherical is just a change of coordinates, so if you take > that into account properly in the weak form then everything is fine. In > particular, you need to account for: >  the change of measure, which gives an extra r^2 * \sin(\phi) factor, if > memory serves >  the change of variables in the gradient terms > > It would be nice to automate this so that it is automatically included in > libMesh's JxW and dphi, which is what Paul was referring to. But the > easiest thing for you in the short term would be to just explicitly deal > with the change of variables yourself. > > Great. Thank you. This will work. PZ > David > > > > > > > On May 9, 2013, at 10:57, "Paul T. Bauman" <ptbauman@...> wrote: > >> What David said is correct (and how I currently deal with cylindrical >>> coordinates). Nevertheless, while there are no formal plans, I've thought >>> it would be nice to try and deal with alternative (to Cartesian) >>> coordinate >>> systems at the libMesh level. E.g. JxW comes premultiplied by r, >>> curl/Laplacian/div/etc formulae have the right terms so that the same >>> code >>> could be used regardless of coordinate system, etc. Alas, it hasn't been >>> high enough priority for me to spend any time thinking about it and >>> proposing how to do it, e.g. whether it should be an FE type, etc. >>> >>> That said, Peter, if you wanted to take a crack at it, I (and probably >>> others) would be happy to give guidance. >>> >>> >>> On Thu, May 9, 2013 at 12:48 PM, David Knezevic >>> <dknezevic@...>**wrote: >>> >>> I'm not sure I understand what you're getting at, but if you write the >>>> PDE in terms of (r,theta,phi), then you can just use libmesh in the >>>> standard way. You'll presumably get sin's, cos's and 1/r terms in the >>>> weak form, but that's no problem... >>>> >>>> >>>> >>>> On 05/09/2013 01:43 PM, Peter Zajac wrote: >>>> >>>>> Dear All, >>>>> >>>>> Is treatment in spherical coordinates an option in Libmesh? >>>>> If not is there a plan to implement it in the near future? >>>>> >>>>> Thank you in advance >>>>> >>>>> >>>>> PZ >>>>> >>>>> **** >>>>  >>>> >>>>> Learn Graph Databases  Download FREE O'Reilly Book >>>>> "Graph Databases" is the definitive new guide to graph databases and >>>>> their applications. This 200page book is written by three acclaimed >>>>> leaders in the field. The early access version is available now. >>>>> Download your free book today! http://p.sf.net/sfu/neotech_**d2d_may<http://p.sf.net/sfu/neotech_d2d_may>; >>>>> ______________________________**_________________ >>>>> Libmeshusers mailing list >>>>> Libmeshusers@...**sourceforge.net<Libmeshusers@...> >>>>> https://lists.sourceforge.net/**lists/listinfo/libmeshusers<https://lists.sourceforge.net/lists/listinfo/libmeshusers>; >>>>> >>>> >>>> >>>> **** >>>>  >>>> Learn Graph Databases  Download FREE O'Reilly Book >>>> "Graph Databases" is the definitive new guide to graph databases and >>>> their applications. This 200page book is written by three acclaimed >>>> leaders in the field. The early access version is available now. >>>> Download your free book today! http://p.sf.net/sfu/neotech_**d2d_may<http://p.sf.net/sfu/neotech_d2d_may>; >>>> ______________________________**_________________ >>>> Libmeshusers mailing list >>>> Libmeshusers@...**sourceforge.net<Libmeshusers@...> >>>> https://lists.sourceforge.net/**lists/listinfo/libmeshusers<https://lists.sourceforge.net/lists/listinfo/libmeshusers>; >>>> >>>> **** >>>  >>> Learn Graph Databases  Download FREE O'Reilly Book >>> "Graph Databases" is the definitive new guide to graph databases and >>> their applications. This 200page book is written by three acclaimed >>> leaders in the field. The early access version is available now. >>> Download your free book today! http://p.sf.net/sfu/neotech_**d2d_may<http://p.sf.net/sfu/neotech_d2d_may>; >>> ______________________________**_________________ >>> Libmeshusers mailing list >>> Libmeshusers@...**sourceforge.net<Libmeshusers@...> >>> https://lists.sourceforge.net/**lists/listinfo/libmeshusers<https://lists.sourceforge.net/lists/listinfo/libmeshusers>; >>> >> > 
From: David Knezevic <dknezevic@se...>  20130509 18:29:19

On 05/09/2013 02:22 PM, PETER ZAJAC wrote: > David, > > I was worried about the volume element for integration. If I use explicit transformations of coordinates to spherical how would I make sure that the volume element for integration changes accordingly. Cartesian > spherical is just a change of coordinates, so if you take that into account properly in the weak form then everything is fine. In particular, you need to account for:  the change of measure, which gives an extra r^2 * \sin(\phi) factor, if memory serves  the change of variables in the gradient terms It would be nice to automate this so that it is automatically included in libMesh's JxW and dphi, which is what Paul was referring to. But the easiest thing for you in the short term would be to just explicitly deal with the change of variables yourself. David On May 9, 2013, at 10:57, "Paul T. Bauman" <ptbauman@...> wrote: >> What David said is correct (and how I currently deal with cylindrical >> coordinates). Nevertheless, while there are no formal plans, I've thought >> it would be nice to try and deal with alternative (to Cartesian) coordinate >> systems at the libMesh level. E.g. JxW comes premultiplied by r, >> curl/Laplacian/div/etc formulae have the right terms so that the same code >> could be used regardless of coordinate system, etc. Alas, it hasn't been >> high enough priority for me to spend any time thinking about it and >> proposing how to do it, e.g. whether it should be an FE type, etc. >> >> That said, Peter, if you wanted to take a crack at it, I (and probably >> others) would be happy to give guidance. >> >> >> On Thu, May 9, 2013 at 12:48 PM, David Knezevic >> <dknezevic@...>wrote: >> >>> I'm not sure I understand what you're getting at, but if you write the >>> PDE in terms of (r,theta,phi), then you can just use libmesh in the >>> standard way. You'll presumably get sin's, cos's and 1/r terms in the >>> weak form, but that's no problem... >>> >>> >>> >>> On 05/09/2013 01:43 PM, Peter Zajac wrote: >>>> Dear All, >>>> >>>> Is treatment in spherical coordinates an option in Libmesh? >>>> If not is there a plan to implement it in the near future? >>>> >>>> Thank you in advance >>>> >>>> >>>> PZ >>>> >>>  >>>> Learn Graph Databases  Download FREE O'Reilly Book >>>> "Graph Databases" is the definitive new guide to graph databases and >>>> their applications. This 200page book is written by three acclaimed >>>> leaders in the field. The early access version is available now. >>>> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may >>>> _______________________________________________ >>>> Libmeshusers mailing list >>>> Libmeshusers@... >>>> https://lists.sourceforge.net/lists/listinfo/libmeshusers >>> >>> >>>  >>> Learn Graph Databases  Download FREE O'Reilly Book >>> "Graph Databases" is the definitive new guide to graph databases and >>> their applications. This 200page book is written by three acclaimed >>> leaders in the field. The early access version is available now. >>> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may >>> _______________________________________________ >>> Libmeshusers mailing list >>> Libmeshusers@... >>> https://lists.sourceforge.net/lists/listinfo/libmeshusers >>> >>  >> Learn Graph Databases  Download FREE O'Reilly Book >> "Graph Databases" is the definitive new guide to graph databases and >> their applications. This 200page book is written by three acclaimed >> leaders in the field. The early access version is available now. >> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may >> _______________________________________________ >> Libmeshusers mailing list >> Libmeshusers@... >> https://lists.sourceforge.net/lists/listinfo/libmeshusers 
From: PETER ZAJAC <peterzajac1@gm...>  20130509 18:22:23

David, I was worried about the volume element for integration. If I use explicit transformations of coordinates to spherical how would I make sure that the volume element for integration changes accordingly. Paul, I am not sure i ll be the best person for the job. With all my honesty (and considering my level of expertise in Libmesh) I might do more harm than good ;) Thank you Peter On May 9, 2013, at 10:57, "Paul T. Bauman" <ptbauman@...> wrote: > What David said is correct (and how I currently deal with cylindrical > coordinates). Nevertheless, while there are no formal plans, I've thought > it would be nice to try and deal with alternative (to Cartesian) coordinate > systems at the libMesh level. E.g. JxW comes premultiplied by r, > curl/Laplacian/div/etc formulae have the right terms so that the same code > could be used regardless of coordinate system, etc. Alas, it hasn't been > high enough priority for me to spend any time thinking about it and > proposing how to do it, e.g. whether it should be an FE type, etc. > > That said, Peter, if you wanted to take a crack at it, I (and probably > others) would be happy to give guidance. > > > On Thu, May 9, 2013 at 12:48 PM, David Knezevic > <dknezevic@...>wrote: > >> I'm not sure I understand what you're getting at, but if you write the >> PDE in terms of (r,theta,phi), then you can just use libmesh in the >> standard way. You'll presumably get sin's, cos's and 1/r terms in the >> weak form, but that's no problem... >> >> >> >> On 05/09/2013 01:43 PM, Peter Zajac wrote: >>> Dear All, >>> >>> Is treatment in spherical coordinates an option in Libmesh? >>> If not is there a plan to implement it in the near future? >>> >>> Thank you in advance >>> >>> >>> PZ >>> >>  >>> Learn Graph Databases  Download FREE O'Reilly Book >>> "Graph Databases" is the definitive new guide to graph databases and >>> their applications. This 200page book is written by three acclaimed >>> leaders in the field. The early access version is available now. >>> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may >>> _______________________________________________ >>> Libmeshusers mailing list >>> Libmeshusers@... >>> https://lists.sourceforge.net/lists/listinfo/libmeshusers >> >> >> >>  >> Learn Graph Databases  Download FREE O'Reilly Book >> "Graph Databases" is the definitive new guide to graph databases and >> their applications. This 200page book is written by three acclaimed >> leaders in the field. The early access version is available now. >> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may >> _______________________________________________ >> Libmeshusers mailing list >> Libmeshusers@... >> https://lists.sourceforge.net/lists/listinfo/libmeshusers >> >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers 
From: Roy Stogner <roystgnr@ic...>  20130509 18:02:00

On Thu, 9 May 2013, Paul T. Bauman wrote: > What David said is correct (and how I currently deal with cylindrical > coordinates). Nevertheless, while there are no formal plans, I've thought > it would be nice to try and deal with alternative (to Cartesian) coordinate > systems at the libMesh level. E.g. JxW comes premultiplied by r, > curl/Laplacian/div/etc formulae have the right terms so that the same code > could be used regardless of coordinate system, etc. Alas, it hasn't been > high enough priority for me to spend any time thinking about it and > proposing how to do it, e.g. whether it should be an FE type, etc. I looked into this too; it's been a long while, IIRC I ran into issues with covariant vs. contravariant vectors in some formulation that made it nonobvious how to enable coordinatesystemindependent code. > That said, Peter, if you wanted to take a crack at it, I (and probably > others) would be happy to give guidance. Likewise.  Roy 
From: Paul T. Bauman <ptbauman@gm...>  20130509 17:57:35

What David said is correct (and how I currently deal with cylindrical coordinates). Nevertheless, while there are no formal plans, I've thought it would be nice to try and deal with alternative (to Cartesian) coordinate systems at the libMesh level. E.g. JxW comes premultiplied by r, curl/Laplacian/div/etc formulae have the right terms so that the same code could be used regardless of coordinate system, etc. Alas, it hasn't been high enough priority for me to spend any time thinking about it and proposing how to do it, e.g. whether it should be an FE type, etc. That said, Peter, if you wanted to take a crack at it, I (and probably others) would be happy to give guidance. On Thu, May 9, 2013 at 12:48 PM, David Knezevic <dknezevic@...>wrote: > I'm not sure I understand what you're getting at, but if you write the > PDE in terms of (r,theta,phi), then you can just use libmesh in the > standard way. You'll presumably get sin's, cos's and 1/r terms in the > weak form, but that's no problem... > > > > On 05/09/2013 01:43 PM, Peter Zajac wrote: > > Dear All, > > > > Is treatment in spherical coordinates an option in Libmesh? > > If not is there a plan to implement it in the near future? > > > > Thank you in advance > > > > > > PZ > > >  > > Learn Graph Databases  Download FREE O'Reilly Book > > "Graph Databases" is the definitive new guide to graph databases and > > their applications. This 200page book is written by three acclaimed > > leaders in the field. The early access version is available now. > > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > > _______________________________________________ > > Libmeshusers mailing list > > Libmeshusers@... > > https://lists.sourceforge.net/lists/listinfo/libmeshusers > > > >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers > 
From: David Knezevic <dknezevic@se...>  20130509 17:48:45

I'm not sure I understand what you're getting at, but if you write the PDE in terms of (r,theta,phi), then you can just use libmesh in the standard way. You'll presumably get sin's, cos's and 1/r terms in the weak form, but that's no problem... On 05/09/2013 01:43 PM, Peter Zajac wrote: > Dear All, > > Is treatment in spherical coordinates an option in Libmesh? > If not is there a plan to implement it in the near future? > > Thank you in advance > > > PZ >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers 
From: Peter Zajac <peterzajac1@gm...>  20130509 17:43:57

Dear All, Is treatment in spherical coordinates an option in Libmesh? If not is there a plan to implement it in the near future? Thank you in advance PZ 
From: Cody Permann <codypermann@gm...>  20130509 16:08:10

On Thu, May 9, 2013 at 9:18 AM, Ataollah Mesgarnejad <amesga1@... > wrote: > > Cody, > > On May 9, 2013, at 9:29 AM, Cody Permann <codypermann@...> wrote: > > > > > On Thu, May 9, 2013 at 8:07 AM, Ataollah Mesgarnejad < > amesga1@...> wrote: > >> Dear all, >> >> I was wondering if anyone has any experience using gamg with libMesh (I'm >> particularly interested in elasticity)? >> >> > It certainly works, however in my very limited experiecne, it's slightly > more tricky to use than Hypre as we've found that it requires a few more > options. Gamg is very flexible and part of PETSc so it ties in nicely. > > > > That's wonderful. Do I need to add anything in the code itself like block > size or ..? Or do you mean the command line options for gamg? > Just the command line options. If you have specific questions, the petsc user list is a great place to ask. Cody > > My main question would be if the geometric part of gamg would work with >> the underlying mesh structure in libMesh? >> > > I'm not sure if I'm missing something with this question. I don't see why > this preconditioner would care about the mesh structure, it's abstracted > well above that level. From libMesh's perspective, it's just another > preconditioner. > > > OK. I'm not very familiar with low level structure in libMesh so I wasn't > sure. > > Thanks, > Ata > > > Cody > > >> >> I would appreciate any comments/recommendations, >> Ata >> >>  >> Learn Graph Databases  Download FREE O'Reilly Book >> "Graph Databases" is the definitive new guide to graph databases and >> their applications. This 200page book is written by three acclaimed >> leaders in the field. The early access version is available now. >> Download your free book today! http://p.sf.net/sfu/neotech_d2d_may >> _______________________________________________ >> Libmeshusers mailing list >> Libmeshusers@... >> https://lists.sourceforge.net/lists/listinfo/libmeshusers >> > > > 
From: Ataollah Mesgarnejad <amesga1@ti...>  20130509 15:18:31

Cody, On May 9, 2013, at 9:29 AM, Cody Permann <codypermann@...> wrote: > > > > On Thu, May 9, 2013 at 8:07 AM, Ataollah Mesgarnejad <amesga1@...> wrote: > Dear all, > > I was wondering if anyone has any experience using gamg with libMesh (I'm particularly interested in elasticity)? > > > It certainly works, however in my very limited experiecne, it's slightly more tricky to use than Hypre as we've found that it requires a few more options. Gamg is very flexible and part of PETSc so it ties in nicely. > That's wonderful. Do I need to add anything in the code itself like block size or ..? Or do you mean the command line options for gamg? > My main question would be if the geometric part of gamg would work with the underlying mesh structure in libMesh? > > I'm not sure if I'm missing something with this question. I don't see why this preconditioner would care about the mesh structure, it's abstracted well above that level. From libMesh's perspective, it's just another preconditioner. OK. I'm not very familiar with low level structure in libMesh so I wasn't sure. Thanks, Ata > > Cody > > > I would appreciate any comments/recommendations, > Ata >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers > 
From: Cody Permann <codypermann@gm...>  20130509 14:29:37

On Thu, May 9, 2013 at 8:07 AM, Ataollah Mesgarnejad <amesga1@... > wrote: > Dear all, > > I was wondering if anyone has any experience using gamg with libMesh (I'm > particularly interested in elasticity)? > > It certainly works, however in my very limited experiecne, it's slightly more tricky to use than Hypre as we've found that it requires a few more options. Gamg is very flexible and part of PETSc so it ties in nicely. > My main question would be if the geometric part of gamg would work with > the underlying mesh structure in libMesh? > I'm not sure if I'm missing something with this question. I don't see why this preconditioner would care about the mesh structure, it's abstracted well above that level. From libMesh's perspective, it's just another preconditioner. Cody > > I would appreciate any comments/recommendations, > Ata > >  > Learn Graph Databases  Download FREE O'Reilly Book > "Graph Databases" is the definitive new guide to graph databases and > their applications. This 200page book is written by three acclaimed > leaders in the field. The early access version is available now. > Download your free book today! http://p.sf.net/sfu/neotech_d2d_may > _______________________________________________ > Libmeshusers mailing list > Libmeshusers@... > https://lists.sourceforge.net/lists/listinfo/libmeshusers > 
From: Ataollah Mesgarnejad <amesga1@ti...>  20130509 14:07:59

Dear all, I was wondering if anyone has any experience using gamg with libMesh (I'm particularly interested in elasticity)? My main question would be if the geometric part of gamg would work with the underlying mesh structure in libMesh? I would appreciate any comments/recommendations, Ata 