> On 19 Oct 2022, at 4:32 PM, TARDIEU Nicolas <nicolas.tard...@edf.fr> wrote: > > Dear Pierre, > > Thank you very much for your answer. I have the same explanation as you for > the code I sent. > But what I would like to do is the following : I have the full matrix A with > fields u, p and t (which are interlaced in the real application). I want to > extract B=A(u+p, u+p). *Then* I would like to extract the (u, u) block from B > - let us call it B_uu. > In fact, B_uu=A_uu but I really need to do the extraction from B. > And I am missing something since I have to play with different numberings > when switching the IS from A to B. > > Is it clear enough ????
That’s cristal clear. If the fields are interlaced, that’s actually easier to do, because you preserve the distribution, and there is less data movement. I’ll try to fix your code in the case where the fields are interlaced if now one gives you another answer in the meantime. Thanks, Pierre > Regards, > Nicolas > -- > Nicolas Tardieu > Ing PhD Computational Mechanics > EDF - R&D Dpt ERMES > PARIS-SACLAY, FRANCE > De : pie...@joliv.et <pie...@joliv.et> > Envoyé : mercredi 19 octobre 2022 14:51 > À : TARDIEU Nicolas <nicolas.tard...@edf.fr> > Cc : petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov> > Objet : Re: [petsc-users] Trouble with ISEmbed > > On two processes, you have a different distribution for u and u+p. > IS Object: 2 MPI processes > type: general > [0] Number of indices in set 5 > [0] 0 0 > [0] 1 1 > [0] 2 2 > [0] 3 3 > [0] 4 4 > [1] Number of indices in set 5 > [1] 0 5 > [1] 1 6 > [1] 2 7 > [1] 3 8 > [1] 4 9 > IS Object: 2 MPI processes > type: general > [0] Number of indices in set 8 > [0] 0 0 > [0] 1 1 > [0] 2 2 > [0] 3 3 > [0] 4 4 > [0] 5 5 > [0] 6 6 > [0] 7 7 > [1] Number of indices in set 7 > [1] 0 8 > [1] 1 9 > [1] 2 10 > [1] 3 11 > [1] 4 12 > [1] 5 13 > [1] 6 14 > ISEmbed() only works on local indices, so when you embed u into u+p, on the > second process, you miss the row/column indices 5, 6, 7 of B = A(u+p, u+p). > Thus, you end up with a matrix of dimension size(u) - 3 = 10 - 3 = 7, with > just the row/column indices 8 and 9 being selected by the second process. > What is it that you want to do exactly? Play with ISEmbed(), or get A(u, u) > without using A but B instead? > > Thanks, > Pierre > > > On 19 Oct 2022, at 12:00 PM, TARDIEU Nicolas via petsc-users > > <petsc-users@mcs.anl.gov> wrote: > > > > Dear PETSc Team, > > > > I am trying to use IS embeding in parallel. > > In order to (try to) understand how it works, I have built a simple > > example, attached to this email. > > > > I consider a 20X20 matrix. The dof (u, p, t) in global numbering are the > > following : > > u: 0..9 p: 10..14 t: 15..19 > > > > I have defined 4 IS to describe the dof u, p, t and the agglomeration of u > > and p, called up. > > I first extract the submatrix matrix(up,up), then I would like to extract > > from it the (u,u) block. > > > > The example runs OK in sequential but I do not obtain the (u,u) block on 2 > > processes. > > > > I have a mistake in the build of the sub-IS but I cannot find it for days. > > > > Best regards, > > Nicolas > > -- > > Nicolas Tardieu > > Ing PhD Computational Mechanics > > EDF - R&D Dpt ERMES > > PARIS-SACLAY, FRANCE > > > > Ce message et toutes les pièces jointes (ci-après le 'Message') sont > > établis à l'intention exclusive des destinataires et les informations qui y > > figurent sont strictement confidentielles. Toute utilisation de ce Message > > non conforme à sa destination, toute diffusion ou toute publication totale > > ou partielle, est interdite sauf autorisation expresse. > > Si vous n'êtes pas le destinataire de ce Message, il vous est interdit de > > le copier, de le faire suivre, de le divulguer ou d'en utiliser tout ou > > partie. Si vous avez reçu ce Message par erreur, merci de le supprimer de > > votre système, ainsi que toutes ses copies, et de n'en garder aucune trace > > sur quelque support que ce soit. Nous vous remercions également d'en > > avertir immédiatement l'expéditeur par retour du message. > > Il est impossible de garantir que les communications par messagerie > > électronique arrivent en temps utile, sont sécurisées ou dénuées de toute > > erreur ou virus. > > ____________________________________________________ > > This message and any attachments (the 'Message') are intended solely for > > the addressees. The information contained in this Message is confidential. > > Any use of information contained in this Message not in accord with its > > purpose, any dissemination or disclosure, either whole or partial, is > > prohibited except formal approval. > > If you are not the addressee, you may not copy, forward, disclose or use > > any part of it. If you have received this message in error, please delete > > it and all copies from your system and notify the sender immediately by > > return message. > > E-mail communication cannot be guaranteed to be timely secure, error or > > virus-free. > > <is_pb.tgz> > > > Ce message et toutes les pièces jointes (ci-après le 'Message') sont établis > à l'intention exclusive des destinataires et les informations qui y figurent > sont strictement confidentielles. Toute utilisation de ce Message non > conforme à sa destination, toute diffusion ou toute publication totale ou > partielle, est interdite sauf autorisation expresse. > Si vous n'êtes pas le destinataire de ce Message, il vous est interdit de le > copier, de le faire suivre, de le divulguer ou d'en utiliser tout ou partie. > Si vous avez reçu ce Message par erreur, merci de le supprimer de votre > système, ainsi que toutes ses copies, et de n'en garder aucune trace sur > quelque support que ce soit. Nous vous remercions également d'en avertir > immédiatement l'expéditeur par retour du message. > Il est impossible de garantir que les communications par messagerie > électronique arrivent en temps utile, sont sécurisées ou dénuées de toute > erreur ou virus. > ____________________________________________________ > This message and any attachments (the 'Message') are intended solely for the > addressees. The information contained in this Message is confidential. Any > use of information contained in this Message not in accord with its purpose, > any dissemination or disclosure, either whole or partial, is prohibited > except formal approval. > If you are not the addressee, you may not copy, forward, disclose or use any > part of it. If you have received this message in error, please delete it and > all copies from your system and notify the sender immediately by return > message. > E-mail communication cannot be guaranteed to be timely secure, error or > virus-free.
