Hello Andrea, On Tue, 2011-05-10 at 12:58 +0100, Andrea Palazzi wrote: > --- Mar 10/5/11, Adam C Powell IV <hazelsct@debian.org> ha scritto: > > > Da: Adam C Powell IV <hazelsct@debian.org> > > Oggetto: Re: ITP: aster -- Finite Element Analysis (FEA) software for engineering simulations > > > > I would like to help in packaging the Code Aster > > software[1] for Debian. > > > Thanks for your interest in the packaging of Code > > Aster. > > > However, you should be aware of a license issue with > > metis-edf: > > > http://glaros.dtc.umn.edu/gkhome/node/686 > > > To unblock, we should consider some uploads in > > non-free and contrib. > > > > How extensive are the differences between metis-edf and > > metis? Might it > > be worth porting those differences to Scotch? Or does > > Code Aster use > > some features of metis not present in Scotch, like > > element-wise > > partitioning (instead of node-wise)? > > Hi, > > I know nothing about mesh partitioning, scotch and metis; however here is > what Cristophe Trohime said to me when we talked about this a month ago > (the quoted text is mine): > > "[...]> As far as I understand, it's actually possible to build CA without > > metis; however some functionalities will not be available > > (RENUM='METIS' in SOLVEUR), and this can be a rather annoying > > problem, since metis is the default renumerator; however, > > if CA can switch automatically to another renum, this may > > become just a performance issue (and a longer list of failing > > tests, if METIS is explicitly called). > > For replacing metis with scotch, the library by itself is already > > there (libscotchmetis), however what is missing are the executables: > > see this thread http://www.code-aster.org/forum2/viewtopic.php?id=14417 > > , where André says "In case you succeed to make the tests from > > liste_internet pass with scotchmetis, I am very interested about your > > build (because it means that you can supply an alternative to onmetis, > > kmetis and onmetis.exe)." > > I had the opportunity to discuss that with Mathieu Courtois, a ASTER developper, last year. > He tells me that if we choose Scotch instead of metis it will be better to call directly without using any additionnal programs. But my guess is this is a lot of work. > > The other point is if you want to rewrite (on)metis with scotch you cannot do it easily. > They are using some calls to metis which do not exist in scotch. > > As far as I understand they prefer to stick to metis which is more widespread than scotch. [...]" > > So, if I get it right CA calls metis via an executable (onmetis, > konmetis, onmetis.exe). Great, that way there's no derivative work and no copyright violation, as there would be if they linked to libmetis (at least in the FSF interpretation). > The difference between metis and metis-edf > is (i think) in these executables and in some other modification to > make it work with CA - maybe the int32/int64 issue. > Those executables are using some library calls that are not implemented > in scotch, and EDF doesn't seems interested to replace metis with scotch. Ah, that's what I was afraid of. This is an issue also for Elmer, though Elmer has an option for node-wise partitioning, which Scotch supports, and which I enable by default, so it works out-of-the-box. If an Elmer user switches that off, they get an error message. Thanks for this additional information. -Adam -- GPG fingerprint: D54D 1AEE B11C CE9B A02B C5DD 526F 01E8 564E E4B6 Engineering consulting with open source tools http://www.opennovation.com/
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