December 2023 - petsc-users - mailman3.cels.anl.gov

Spring 2024 PETSc meeting and release announcement 3.20
by Barry Smith 09 Nov '24

09 Nov '24

The May 23-24, 2024 PETSc annual meeting in Cologne Germany website is now available: https://cds.uni-koeln.de/en/workshops/petsc-2024/home Please register and start making your travel plans. We are pleased to announce the release of PETSc version 3.20.0 at https://petsc.org/release/download/ A list of the major changes and updates can be found at https://petsc.org/release/changes/320/ The release tarball location is changed from https://ftp.mcs.anl.gov/pub/petsc to https://web.cels.anl.gov/projects/petsc/download The final update to petsc-3.19 i.e petsc-3.19.6 is also available We recommend upgrading to PETSc 3.20.0 soon. As always, please report problems to petsc-maint(a)mcs.anl.gov and ask questions at petsc-users(a)mcs.anl.gov This release includes contributions from David Ham Iglesia Dolci Jack Betteridge Koki Sagiyama Marcin Rogowski Nathan Collier Aidan Hamilton Albert Cowie Barry Smith Blaise Bourdin Connor Ward David Andrs David Wells Duncan Campbell Hansol Suh Hong Zhang Jacob Faibussowitsch James Wright Jed Brown jeremy theler Joseph Pusztay Jose Roman Junchao Zhang Lisandro Dalcin Mark Adams Matthew Knepley Mr. Hong Zhang Pablo Brubeck Pierre Jolivet Pieter Ghysels Richard Tran Mills Satish Balay Sebastian Grimberg Stefano Zampini Suyash Tandon Toby Isaac YANG Zongze Zach Atkins and bug reports/proposed improvements received from Carl-Johan Thore Chris Douglas Daniel@OLCF Duan Junming Edoardo alinovi Philip Fackler Frederic Vi Getnet Betrie Aron Graham Hongrui Yu James Wright Jin Chen Jonas Lundgren Karsten Lettmann Boris Kaus LEONARDO MUTTI Maciej Lewkowicz maitri ksh Milan Pelletier Mr. Hong Zhang Ngoc Mai Monica Huynh Peng Wang Sébastien Gilles Daniel Taller Vibhas Mishra Wei Liu Li Xiaoye As always, thanks for your support, Barry

1 2

How to combine different element types into a single DMPlex?
by Eric Chamberland 01 Aug '24

01 Aug '24

Hi, while playing with DMPlexBuildFromCellListParallel, I noticed we have to specify "numCorners" which is a fixed value, then gives a fixed number of nodes for a series of elements. How can I then add, for example, triangles and quadrangles into a DMPlex? Thanks, Eric -- Eric Chamberland, ing., M. Ing Professionnel de recherche GIREF/Université Laval (418) 656-2131 poste 41 22 42

4 13

Help with Integrating PETSc into Fortran Groundwater Flow Simulation Code
by Shatanawi, Sawsan Muhammad 18 May '24

18 May '24

Hello everyone, I hope this email finds you well. My Name is Sawsan Shatanawi, and I am currently working on developing a Fortran code for simulating groundwater flow in a 3D system. The code involves solving a nonlinear system, and I have created the matrix to be solved using the PCG solver and Picard iteration. However, when I tried to assign it as a PETSc matrix I started getting a lot of error messages. I am kindly asking if someone can help me, I would be happy to share my code with him/her. Please find the attached file contains a list of errors I have gotten Thank you in advance for your time and assistance. Best regards, Sawsan

5 29

HDF5 corruption
by Adrian Croucher 13 May '24

13 May '24

hi, One of the users of my PETSc-based code has reported that HDF5 output files can be corrupted and unusable if e.g. the run is killed. I've just done a bit of reading about this and it appears to be a known issue with HDF5. Some people suggest flushing the HDF5 file periodically to help prevent data loss. I had a look at PetscViewerFlush() but it doesn't seem to be implemented for the HDF5 viewer- is that correct? I am currently calling PetscViewerHDF5Open() once at the start of the run and closing it at the end. Some other people suggest doing this before and after each write instead. Is there likely to be a significant performance penalty in doing that? I gather HDF5 journaling has been promised for a while to get around this problem but as far as I can see it hasn't materialised yet... Regards, Adrian -- Dr Adrian Croucher Senior Research Fellow Department of Engineering Science University of Auckland, New Zealand email: a.croucher(a)auckland.ac.nz tel: +64 (0)9 923 4611

4 17

Configure error while building PETSc with CUDA/MVAPICH2-GDR
by Sreeram R Venkat 19 Apr '24

19 Apr '24

I am trying to build PETSc with CUDA using the CUDA-Aware MVAPICH2-GDR. Here is my configure command: ./configure PETSC_ARCH=linux-c-debug-mvapich2-gdr --download-hypre --with-cuda=true --cuda-dir=$TACC_CUDA_DIR --with-hdf5=true --with-hdf5-dir=$TACC_PHDF5_DIR --download-elemental --download-metis --download-parmetis --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 which errors with: UNABLE to CONFIGURE with GIVEN OPTIONS (see configure.log for details): --------------------------------------------------------------------------------------------- CUDA compile failed with arch flags " -ccbin mpic++ -std=c++14 -Xcompiler -fPIC -Xcompiler -fvisibility=hidden -g -lineinfo -gencode arch=compute_80,code=sm_80" generated from "--with-cuda-arch=80" The same configure command works when I use the Intel MPI and I can build with CUDA. The full config.log file is attached. Please let me know if you need any other information. I appreciate your help with this. Thanks, Sreeram

6 15

Using PETSc GPU backend
by Ng, Cho-Kuen 13 Apr '24

13 Apr '24

I installed PETSc on Perlmutter using "spack install petsc+cuda+zoltan" and used it by "spack load petsc/fwge6pf". Then I compiled the application code (purely CPU code) linking to the petsc package, hoping that I can get performance improvement using the petsc GPU backend. However, the timing was the same using the same number of MPI tasks with and without GPU accelerators. Have I missed something in the process, for example, setting up PETSc options at runtime to use the GPU backend? Thanks, Cho

5 27

Fortran Interface NULL object / Casting
by Nicholas Arnold-Medabalimi 23 Feb '24

23 Feb '24

Hi Petsc Users I am trying to use DMAddField in a Fortran code. I had some questions on casting/passing NULL. I follow how to pass NULL for standard types (INT, CHAR, etc). Is there a method/best practice for passing NULL for Petsc type arguments? (In this case DMAddLabel I'd want to pass NULL to a DMLabel Parameter not an intrinsic type) For the 2nd question, In some cases in C we would cast a more specific object to Petsc Object DMAddField(dm, NULL, (PetscObject)fvm); (where fvm is a PetscFVM type) Is there a method or practice to do the same in Fortran. Thanks Nicholas -- Nicholas Arnold-Medabalimi Ph.D. Candidate Computational Aeroscience Lab University of Michigan

3 2

Re: [petsc-users] Matvecs and KSPSolves with multiple vectors
by Pierre Jolivet 21 Dec '23

21 Dec '23

Unfortunately, I am not able to reproduce such a failure with your input matrix. I’ve used ex79 that I linked previously and the system is properly solved. $ ./ex79 -pc_type hypre -ksp_type hpddm -ksp_hpddm_type cg -ksp_converged_reason -ksp_view_mat ascii::ascii_info -ksp_view_rhs ascii::ascii_info Linear solve converged due to CONVERGED_RTOL iterations 6 Mat Object: 1 MPI process type: seqaijcusparse rows=289, cols=289 total: nonzeros=2401, allocated nonzeros=2401 total number of mallocs used during MatSetValues calls=0 not using I-node routines Mat Object: 1 MPI process type: seqdensecuda rows=289, cols=10 total: nonzeros=2890, allocated nonzeros=2890 total number of mallocs used during MatSetValues calls=0 You mentioned in a subsequent email that you are interested in systems with at most 1E6 unknowns, and up to 1E4 right-hand sides. I’m not sure you can expect significant gains from using GPU for such systems. Probably, the fastest approach would indeed be -pc_type lu -ksp_type preonly -ksp_matsolve_batch_size 100 or something, depending on the memory available on your host. Thanks, Pierre > On 15 Dec 2023, at 9:52 PM, Sreeram R Venkat <srvenkat(a)utexas.edu> wrote: > > Here are the ksp_view files. I set the options -ksp_error_if_not_converged to try to get the vectors that caused the error. I noticed that some of the KSPMatSolves converge while others don't. In the code, the solves are called as: > > input vector v --> insert data of v into a dense mat --> KSPMatSolve() --> MatMatMult() --> KSPMatSolve() --> insert data of dense mat into output vector w -- output w > > The operator used in the KSP is a Laplacian-like operator, and the MatMatMult is with a Mass Matrix. The whole thing is supposed to be a solve with a biharmonic-like operator. I can also run it with only the first KSPMatSolve (i.e. just a Laplacian-like operator). In that case, the KSP reportedly converges after 0 iterations (see the next line), but this causes problems in other parts of the code later on. > > I saw that sometimes the first KSPMatSolve "converges" after 0 iterations due to CONVERGED_RTOL. Then, the second KSPMatSolve produces a NaN/Inf. I tried setting ksp_min_it, but that didn't seem to do anything. > > I'll keep trying different options and also try to get the MWE made (this KSPMatSolve is pretty performance critical for us). > > Thanks for all your help, > Sreeram > > On Fri, Dec 15, 2023 at 1:01 AM Pierre Jolivet <pierre(a)joliv.et <mailto:[email protected]>> wrote: >> >>> On 14 Dec 2023, at 11:45 PM, Sreeram R Venkat <srvenkat(a)utexas.edu <mailto:[email protected]>> wrote: >>> >>> Thanks, I will try to create a minimal reproducible example. This may take me some time though, as I need to figure out how to extract only the relevant parts (the full program this solve is used in is getting quite complex). >> >> You could just do -ksp_view_mat binary:Amat.bin -ksp_view_pmat binary:Pmat.bin -ksp_view_rhs binary:rhs.bin and send me those three files (I’m guessing your are using double-precision scalars with 32-bit PetscInt). >> >>> I'll also try out some of the BoomerAMG options to see if that helps. >> >> These should work (this is where all “PCMatApply()-ready” PC are being tested): https://petsc.org/release/src/ksp/ksp/tutorials/ex79.c.html#line215 >> You can see it’s also testing PCHYPRE + KSPHPDDM on device (but not with HIP). >> I’m aware the performance should not be optimal (see your comment about host/device copies), I’ve money to hire someone to work on this but: a) I need to find the correct engineer/post-doc, b) I currently don’t have good use cases (of course, I could generate a synthetic benchmark, for science). >> So even if you send me the three Mat, a MWE would be appreciated if the KSPMatSolve() is performance-critical for you (see point b) from above). >> >> Thanks, >> Pierre >> >>> Thanks, >>> Sreeram >>> >>> On Thu, Dec 14, 2023, 1:12 PM Pierre Jolivet <pierre(a)joliv.et <mailto:[email protected]>> wrote: >>>> >>>> >>>>> On 14 Dec 2023, at 8:02 PM, Sreeram R Venkat <srvenkat(a)utexas.edu <mailto:[email protected]>> wrote: >>>>> >>>>> Hello Pierre, >>>>> >>>>> Thank you for your reply. I tried out the HPDDM CG as you said, and it seems to be doing the batched solves, but the KSP is not converging due to a NaN or Inf being generated. I also noticed there are a lot of host-to-device and device-to-host copies of the matrices (the non-batched KSP solve did not have any memcopies). I have attached dump.0 again. Could you please take a look? >>>> >>>> Yes, but you’d need to send me something I can run with your set of options (if you are more confident doing this in private, you can remove the list from c/c). >>>> Not all BoomerAMG smoothers handle blocks of right-hand sides, and there is not much error checking, so instead of erroring out, this may be the reason why you are getting garbage. >>>> >>>> Thanks, >>>> Pierre >>>> >>>>> Thanks, >>>>> Sreeram >>>>> >>>>> On Thu, Dec 14, 2023 at 12:42 AM Pierre Jolivet <pierre(a)joliv.et <mailto:[email protected]>> wrote: >>>>>> Hello Sreeram, >>>>>> KSPCG (PETSc implementation of CG) does not handle solves with multiple columns at once. >>>>>> There is only a single native PETSc KSP implementation which handles solves with multiple columns at once: KSPPREONLY. >>>>>> If you use --download-hpddm, you can use a CG (or GMRES, or more advanced methods) implementation which handles solves with multiple columns at once (via -ksp_type hpddm -ksp_hpddm_type cg or KSPSetType(ksp, KSPHPDDM); KSPHPDDMSetType(ksp, KSP_HPDDM_TYPE_CG);). >>>>>> I’m the main author of HPDDM, there is preliminary support for device matrices, but if it’s not working as intended/not faster than column by column, I’d be happy to have a deeper look (maybe in private), because most (if not all) of my users interested in (pseudo-)block Krylov solvers (i.e., solvers that treat right-hand sides in a single go) are using plain host matrices. >>>>>> >>>>>> Thanks, >>>>>> Pierre >>>>>> >>>>>> PS: you could have a look at https://www.sciencedirect.com/science/article/abs/pii/S0898122121000055 to understand the philosophy behind block iterative methods in PETSc (and in HPDDM), src/mat/tests/ex237.c, the benchmark I mentioned earlier, was developed in the context of this paper to produce Figures 2-3. Note that this paper is now slightly outdated, since then, PCHYPRE and PCMG (among others) have been made “PCMatApply()-ready”. >>>>>> >>>>>>> On 13 Dec 2023, at 11:05 PM, Sreeram R Venkat <srvenkat(a)utexas.edu <mailto:[email protected]>> wrote: >>>>>>> >>>>>>> Hello Pierre, >>>>>>> >>>>>>> I am trying out the KSPMatSolve with the BoomerAMG preconditioner. However, I am noticing that it is still solving column by column (this is stated explicitly in the info dump attached). I looked at the code for KSPMatSolve_Private() and saw that as long as ksp->ops->matsolve is true, it should do the batched solve, though I'm not sure where that gets set. >>>>>>> >>>>>>> I am using the options -pc_type hypre -pc_hypre_type boomeramg when running the code. >>>>>>> >>>>>>> Can you please help me with this? >>>>>>> >>>>>>> Thanks, >>>>>>> Sreeram >>>>>>> >>>>>>> >>>>>>> On Thu, Dec 7, 2023 at 4:04 PM Mark Adams <mfadams(a)lbl.gov <mailto:[email protected]>> wrote: >>>>>>>> N.B., AMGX interface is a bit experimental. >>>>>>>> Mark >>>>>>>> >>>>>>>> On Thu, Dec 7, 2023 at 4:11 PM Sreeram R Venkat <srvenkat(a)utexas.edu <mailto:[email protected]>> wrote: >>>>>>>>> Oh, in that case I will try out BoomerAMG. Getting AMGX to build correctly was also tricky so hopefully the HYPRE build will be easier. >>>>>>>>> >>>>>>>>> Thanks, >>>>>>>>> Sreeram >>>>>>>>> >>>>>>>>> On Thu, Dec 7, 2023, 3:03 PM Pierre Jolivet <pierre(a)joliv.et <mailto:[email protected]>> wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>> On 7 Dec 2023, at 9:37 PM, Sreeram R Venkat <srvenkat(a)utexas.edu <mailto:[email protected]>> wrote: >>>>>>>>>>> >>>>>>>>>>> Thank you Barry and Pierre; I will proceed with the first option. >>>>>>>>>>> >>>>>>>>>>> I want to use the AMGX preconditioner for the KSP. I will try it out and see how it performs. >>>>>>>>>> >>>>>>>>>> Just FYI, AMGX does not handle systems with multiple RHS, and thus has no PCMatApply() implementation. >>>>>>>>>> BoomerAMG does, and there is a PCMatApply_HYPRE_BoomerAMG() implementation. >>>>>>>>>> But let us know if you need assistance figuring things out. >>>>>>>>>> >>>>>>>>>> Thanks, >>>>>>>>>> Pierre >>>>>>>>>> >>>>>>>>>>> Thanks, >>>>>>>>>>> Sreeram >>>>>>>>>>> >>>>>>>>>>> On Thu, Dec 7, 2023 at 2:02 PM Pierre Jolivet <pierre(a)joliv.et <mailto:[email protected]>> wrote: >>>>>>>>>>>> To expand on Barry’s answer, we have observed repeatedly that MatMatMult with MatAIJ performs better than MatMult with MatMAIJ, you can reproduce this on your own with https://petsc.org/release/src/mat/tests/ex237.c.html. >>>>>>>>>>>> Also, I’m guessing you are using some sort of preconditioner within your KSP. >>>>>>>>>>>> Not all are “KSPMatSolve-ready”, i.e., they may treat blocks of right-hand sides column by column, which is very inefficient. >>>>>>>>>>>> You could run your code with -info dump and send us dump.0 to see what needs to be done on our end to make things more efficient, should you not be satisfied with the current performance of the code. >>>>>>>>>>>> >>>>>>>>>>>> Thanks, >>>>>>>>>>>> Pierre >>>>>>>>>>>> >>>>>>>>>>>>> On 7 Dec 2023, at 8:34 PM, Barry Smith <bsmith(a)petsc.dev <mailto:[email protected]>> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>>> On Dec 7, 2023, at 1:17 PM, Sreeram R Venkat <srvenkat(a)utexas.edu <mailto:[email protected]>> wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>> I have 2 sequential matrices M and R (both MATSEQAIJCUSPARSE of size n x n) and a vector v of size n*m. v = [v_1 , v_2 ,... , v_m] where v_i has size n. The data for v can be stored either in column-major or row-major order. Now, I want to do 2 types of operations: >>>>>>>>>>>>>> >>>>>>>>>>>>>> 1. Matvecs of the form M*v_i = w_i, for i = 1..m. >>>>>>>>>>>>>> 2. KSPSolves of the form R*x_i = v_i, for i = 1..m. >>>>>>>>>>>>>> >>>>>>>>>>>>>> From what I have read on the documentation, I can think of 2 approaches. >>>>>>>>>>>>>> >>>>>>>>>>>>>> 1. Get the pointer to the data in v (column-major) and use it to create a dense matrix V. Then do a MatMatMult with M*V = W, and take the data pointer of W to create the vector w. For KSPSolves, use KSPMatSolve with R and V. >>>>>>>>>>>>>> >>>>>>>>>>>>>> 2. Create a MATMAIJ using M/R and use that for matvecs directly with the vector v. I don't know if KSPSolve with the MATMAIJ will know that it is a multiple RHS system and act accordingly. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Which would be the more efficient option? >>>>>>>>>>>>> >>>>>>>>>>>>> Use 1. >>>>>>>>>>>>>> >>>>>>>>>>>>>> As a side-note, I am also wondering if there is a way to use row-major storage of the vector v. >>>>>>>>>>>>> >>>>>>>>>>>>> No >>>>>>>>>>>>> >>>>>>>>>>>>>> The reason is that this could allow for more coalesced memory access when doing matvecs. >>>>>>>>>>>>> >>>>>>>>>>>>> PETSc matrix-vector products use BLAS GMEV matrix-vector products for the computation so in theory they should already be well-optimized >>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Thanks, >>>>>>>>>>>>>> Sreeram >>>>>>>>>>>> >>>>>>>>>> >>>>>>> <dump.0> >>>>>> >>>>> <dump.0> >>>> >> > <Pmat.bin><Amat.bin><rhs.bin>

4 7

TS docs wrong URLs in Examples
by Niclas Götting 21 Dec '23

21 Dec '23

Hi all, I noticed that all links to the examples under https://petsc.org/release/manualpages/TS/TS/ point to the wrong URL. Instead of src/ts/**/*, they point to src/sys/**/*, which does not seem to be right. This definitely is a minor issue, but I couldn't see an obvious fix via "Edit this page", so here is the e-mail. Best regards Niclas

2 2

Re: [petsc-users] SLEPc/NEP for shell matrice T(lambda) and T'(lambda)
by Kenneth C Hall 21 Dec '23

21 Dec '23

Jose, I have been revisiting the issue of SLEPc/NEP for shell matrices T(lambda) and T'(lambda). I am having problems running SLEPc/NEP with -nep_type nleigs. I have compiled two versions of PETSc/SLEPc: petsc-arch-real / slepc-arch-real ./configure --with-cc=gcc-13 --with-cxx=g++-13 --with-fc=gfortran --COPTFLAGS='-O3 -fopenmp' --CXXOPTFLAGS='-O3 -fopenmp' --FOPTFLAGS='-O3 -fopenmp' --with-debugging=1 --with-logging=1 --with-scalar-type=real --with-precision=double --download-fblaslapack --with-openmp --with-mpi=0 petsc-arch-complex / slepc-arch-complex ./configure --with-cc=gcc-13 --with-cxx=g++-13 --with-fc=gfortran --COPTFLAGS='-O3 -fopenmp' --CXXOPTFLAGS='-O3 -fopenmp' --FOPTFLAGS='-O3 -fopenmp' --with-debugging=1 --with-logging=1 --with-scalar-type=complex --with-precision=double --download-fblaslapack --with-openmp --with-mpi=0 I use gfortran on an Apple Mac Mini M1. Both the PETSc and SLEPc versions are the latest development versions as of today (a6690fd8 and 267bd1cd, respectively). I ran the ex54f90 test cases: % main-arch-real -nep_type slp -nep_slp_ksp_type gmres -nep_slp_pc_type none % main-arch-complex -nep_type slp -nep_slp_ksp_type gmres -nep_slp_pc_type none % main-arch-real -nep_type nleigs -rg_interval_endpoints 0.2,1.1 -nep_nleigs_ksp_type gmres -nep_nleigs_pc_type none % main-arch-complex -nep_type nleigs -rg_interval_endpoints 0.2,1.1,-.1,.1 -nep_nleigs_ksp_type gmres -nep_nleigs_pc_type none Both the slp cases ran as expected and gave the correct answer. However, both the real and complex architectures failed for the nleigs case. For the complex case, none of the callback functions appear to have been called. For the real case, only the MatMult_A routine appears to be called, 100 times and returns each time, sweeping over lambda from 0.2 to 1.1. Any suggestions would be welcome. Best regards, Kenneth Hall On 10/18/23, 9:16 AM, "Jose E. Roman" <jroman(a)dsic.upv.es <mailto:[email protected]>> wrote: By the way, the MATOP_DESTROY stuff produced segmentation fault in some compilers (in gfortran it worked well). The reason was having the callback functions inside CONTAINS, that is why we have removed it and used regular subroutines instead. Jose > El 18 oct 2023, a las 15:11, Kenneth C Hall <kenneth.c.hall(a)duke.edu <mailto:[email protected]>> escribió: > > Jose, > > Thank you. I have downloaded and will take a look. I will try the new example and then implement in my actual problem. I will keep you posted as to my results. > > Thank you and best regards, > Kenneth > > From: Jose E. Roman <jroman(a)dsic.upv.es <mailto:[email protected]>> > Sent: Tuesday, October 17, 2023 2:31 PM > To: Kenneth C Hall <kenneth.c.hall(a)duke.edu <mailto:[email protected]>> > Cc: petsc-users(a)mcs.anl.gov <mailto:[email protected]> <petsc-users(a)mcs.anl.gov <mailto:[email protected]>> > Subject: Re: [petsc-users] SLEPc/NEP for shell matrice T(lambda) and T'(lambda) > > Kenneth, > > I have worked a bit more on your example and put it in SLEPc https://urldefense.com/v3/__https://gitlab.com/slepc/slepc/-/merge_requests… <https://urldefense.com/v3/__https://gitlab.com/slepc/slepc/-/merge_requests…> > This version also has MATOP_DESTROY to avoid memory leaks. > > Thanks. > Jose > > > > El 12 oct 2023, a las 20:59, Kenneth C Hall <kenneth.c.hall(a)duke.edu <mailto:[email protected]>> escribió: > > > > Jose, > > > > Thanks very much for this. I will give it a try and let you know how it works. > > > > Best regards, > > Kenneth > > > > From: Jose E. Roman <jroman(a)dsic.upv.es <mailto:[email protected]>> > > Date: Thursday, October 12, 2023 at 2:12 PM > > To: Kenneth C Hall <kenneth.c.hall(a)duke.edu <mailto:[email protected]>> > > Cc: petsc-users(a)mcs.anl.gov <mailto:[email protected]> <petsc-users(a)mcs.anl.gov <mailto:[email protected]>> > > Subject: Re: [petsc-users] SLEPc/NEP for shell matrice T(lambda) and T'(lambda) > > > > I am attaching your example modified with the context stuff. > > > > With the PETSc branch that I indicated, now it works with NLEIGS, for instance: > > > > $ ./test_nep -nep_nleigs_ksp_type gmres -nep_nleigs_pc_type none -rg_interval_endpoints 0.2,1.1 -nep_target 0.8 -nep_nev 5 -n 400 -nep_monitor -nep_view -nep_error_relative ::ascii_info_detail > > > > And also other solvers such as SLP: > > > > $ ./test_nep -nep_type slp -nep_slp_ksp_type gmres -nep_slp_pc_type none -nep_target 0.8 -nep_nev 5 -n 400 -nep_monitor -nep_error_relative ::ascii_info_detail > > > > I will clean the example code an add it as a SLEPc example. > > > > Regards, > > Jose > > > > > > > El 11 oct 2023, a las 17:27, Kenneth C Hall <kenneth.c.hall(a)duke.edu <mailto:[email protected]>> escribió: > > > > > > Jose, > > > > > > Thanks very much for your help with this. Greatly appreciated. I will look at the MR. Please let me know if you do get the Fortran example working. > > > > > > Thanks, and best regards, > > > Kenneth > > >

2 1