From: Vikram G. <sim...@gm...> - 2012-09-17 17:29:12
|
All, Two questions: 1) Do we have any automatic differentiation capabilities in libMesh (apart from numerical jacobians) ? Also, is there some good automatic differentiation software that someone can recommend ? 2) Does anybody have any experience building a CO2 sequestration (or related) application in libMesh ? Thanks. -- Vikram Garg http://users.ices.utexas.edu/~vikram/ http://www.runforindia.org/runners/vikramg |
From: Roy S. <roy...@ic...> - 2012-09-17 17:51:26
|
On Mon, 17 Sep 2012, Vikram Garg wrote: > 1) Do we have any automatic differentiation capabilities in libMesh > (apart from numerical jacobians) ? Also, is there some good > automatic differentiation software that someone can recommend ? You're welcome to use my AD tools. Do you have svn access to pecos/utilities/dualnumber? That's got the latest version, but I think there's been a public release of a nearly-up-to-date version along with MASA: https://red.ices.utexas.edu/projects/software/wiki/MASA The main advantage with those basic tools (dualnumber.h and sparsearray.h) is simplicity; two ~500 line headers gives you arbitrary levels of mixed partial derivatives of arbitrary dimensionality. There are some more advanced headers in there for sparse vectors and tensors if you want to trade higher efficiency for greater debugging difficulty. Long-term I'd like to add AD support to FEMSystem, but I haven't figured out the best architecture yet. To do maximally fancy compile-time things with sparse data types you want your physics functions to be templated around their input arguments, but to do the usual FEMSystem tricks we use virtual functions, and templated virtual functions don't exist. --- Roy |
From: John P. <jwp...@gm...> - 2012-09-17 18:14:58
|
On Mon, Sep 17, 2012 at 11:28 AM, Vikram Garg <sim...@gm...> wrote: > > 2) Does anybody have any experience building a CO2 sequestration (or > related) application in libMesh ? These guys used libmesh for a CO2 sequestration benchmark study: H. Class et al. A benchmark study on problems related to CO2 storage in geologic formations. Computational Geosciences, 13(4):409-434, December 2009. http://dx.doi.org/10.1007/s10596-009-9146-x. -- John |
From: Derek G. <fri...@gm...> - 2012-09-17 18:20:51
|
Sacado is the AD package in Trilinos: http://trilinos.sandia.gov/packages/sacado/index.html It works off expression templating and can be dealt with in an object-oriented code (although not optimally in my experience). If you get it working well with libMesh I would be interested in how you did it. Another question: Are you sure you need AD? If you're just trying to compute Jacobian entries and you're doing fully-coupled solves of multiple physics... you might think about using Jacobian Free Newton-Krylov (JFNK) instead. This is what we do with MOOSE. We've done some preliminary stuff on CO2 sequestration with MOOSE and it's worked well... If you're using it for adjoints / sensitivity stuff then there might be no other option.... Derek On Mon, Sep 17, 2012 at 12:14 PM, John Peterson <jwp...@gm...>wrote: > On Mon, Sep 17, 2012 at 11:28 AM, Vikram Garg <sim...@gm...> > wrote: > > > > 2) Does anybody have any experience building a CO2 sequestration (or > > related) application in libMesh ? > > These guys used libmesh for a CO2 sequestration benchmark study: > > H. Class et al. A benchmark study on problems related to CO2 storage > in geologic formations. Computational Geosciences, 13(4):409-434, > December 2009. http://dx.doi.org/10.1007/s10596-009-9146-x. > > -- > John > > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Libmesh-devel mailing list > Lib...@li... > https://lists.sourceforge.net/lists/listinfo/libmesh-devel > |
From: Vikram G. <vik...@gm...> - 2012-09-17 19:28:38
|
Thanks guys. Was asking on behalf of a final year PhD student here at MIT, he has a new method for inferring parameters, basically focuses directly on relevant QoIs for prediction rather than all parameters (strong parallels to goal oriented adaptivity). We are trying to see if using libMesh can be useful to him to demonstrate the method on a CO2 sequestration problem. He needs AD for more than Jacobian entries. He is doing an optimization loop, where he needs AD to compute the gradient for use in the optimization routine. Basically getting derivatives of the stiffness matrix entries w.r.t the parameters. Thanks. On Mon, Sep 17, 2012 at 2:20 PM, Derek Gaston <fri...@gm...> wrote: > Sacado is the AD package in Trilinos: > http://trilinos.sandia.gov/packages/sacado/index.html > > It works off expression templating and can be dealt with in an > object-oriented code (although not optimally in my experience). > > If you get it working well with libMesh I would be interested in how you > did it. > > Another question: Are you sure you need AD? If you're just trying to > compute Jacobian entries and you're doing fully-coupled solves of multiple > physics... you might think about using Jacobian Free Newton-Krylov (JFNK) > instead. This is what we do with MOOSE. We've done some preliminary stuff > on CO2 sequestration with MOOSE and it's worked well... > > If you're using it for adjoints / sensitivity stuff then there might be no > other option.... > > Derek > > On Mon, Sep 17, 2012 at 12:14 PM, John Peterson <jwp...@gm...>wrote: > >> On Mon, Sep 17, 2012 at 11:28 AM, Vikram Garg <sim...@gm...> >> wrote: >> > >> > 2) Does anybody have any experience building a CO2 sequestration (or >> > related) application in libMesh ? >> >> These guys used libmesh for a CO2 sequestration benchmark study: >> >> H. Class et al. A benchmark study on problems related to CO2 storage >> in geologic formations. Computational Geosciences, 13(4):409-434, >> December 2009. http://dx.doi.org/10.1007/s10596-009-9146-x. >> >> -- >> John >> >> >> ------------------------------------------------------------------------------ >> Live Security Virtual Conference >> Exclusive live event will cover all the ways today's security and >> threat landscape has changed and how IT managers can respond. Discussions >> will include endpoint security, mobile security and the latest in malware >> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >> _______________________________________________ >> Libmesh-devel mailing list >> Lib...@li... >> https://lists.sourceforge.net/lists/listinfo/libmesh-devel >> > > -- Vikram Garg http://users.ices.utexas.edu/~vikram/ http://www.runforindia.org/runners/vikramg |