MatSolve() and MatMatSolve() will not return the transpose of the solution, they will return the solution. If you want the transpose solve you can use MatSolveTranspose() for a single Vec or use MatMatSolve() for the matrix case after transposing the original matrix if you want the transpose.
Barry On Jul 5, 2011, at 12:17 PM, Adam Byrd wrote: > I have working code that produces the correct answer now, thank you. One > (hopefully) final question, though. The solution is actually transposed. What > causes this? Presumably I can use MatMatSolveTranspose to get around this, > but there's no man page and I want to be sure of what will happen in all > cases. > > Respectfully, > Adam > > On Thu, Jun 30, 2011 at 4:18 PM, Hong Zhang <hzhang at mcs.anl.gov> wrote: > Add > ierr = MatGetOrdering(testMat,MATORDERING_ND,&isrow,&iscol);CHKERRQ(ierr); > before the line > ierr = MatFactorInfoInitialize(&luinfo);CHKERRQ(ierr); > > Somehow, your matrix is numerically singular. With > MATORDERING_NATURAL > I get > [0]PETSC ERROR: Detected zero pivot in LU factorization > > even using MATDENSE matrix format, which calls lapack. > With MATORDERING_ND, I get useless inverseMat. > > The modified code I used is attached. > > Hong > > On Thu, Jun 30, 2011 at 2:30 PM, Adam Byrd <adam1.byrd at gmail.com> wrote: > > I'm trying to work through what I need to do, again by practicing with a > > small scale random problem. The general order of events seems to be: create > > a matrix, fill it, assemble it, factor it, then one can use solvers with it. > > When I use MatLUFactor on my matrix before using it with a solver I get this > > error: > > [0]PETSC ERROR: --------------------- Error Message > > ------------------------------------ > > [0]PETSC ERROR: Null argument, when expecting valid pointer! > > [0]PETSC ERROR: Null Object: Parameter # 1! > > [0]PETSC ERROR: > > ------------------------------------------------------------------------ > > [0]PETSC ERROR: Petsc Release Version 3.1.0, Patch 8, Thu Mar 17 13:37:48 > > CDT 2011 > > [0]PETSC ERROR: See docs/changes/index.html for recent updates. > > [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting. > > [0]PETSC ERROR: See docs/index.html for manual pages. > > [0]PETSC ERROR: > > ------------------------------------------------------------------------ > > [0]PETSC ERROR: ./test on a osx-gnu-c named Macintosh-3.local by adambyrd > > Thu Jun 30 15:27:30 2011 > > [0]PETSC ERROR: Libraries linked from > > /Users/adambyrd/soft/petsc-3.1-p8/osx-gnu-cpp/lib > > [0]PETSC ERROR: Configure run at Tue Jun 28 12:56:55 2011 > > [0]PETSC ERROR: Configure options PETSC_ARCH=osx-gnu-cpp --with-fc=gfortran > > -download-f-blas-lapack=1 --download-mpich=1 --with-scalar-type=complex > > --with-clanguage=c++ > > [0]PETSC ERROR: > > ------------------------------------------------------------------------ > > [0]PETSC ERROR: ISInvertPermutation() line 209 in > > src/vec/is/interface/index.c > > [0]PETSC ERROR: MatLUFactorSymbolic_SeqAIJ() line 306 in > > src/mat/impls/aij/seq/aijfact.c > > [0]PETSC ERROR: MatLUFactorSymbolic() line 2534 in > > src/mat/interface/matrix.c > > [0]PETSC ERROR: MatLUFactor_SeqAIJ() line 945 in > > src/mat/impls/aij/seq/aijfact.c > > [0]PETSC ERROR: MatLUFactor() line 2417 in src/mat/interface/matrix.c > > [0]PETSC ERROR: main() line 62 in WDtest.cpp > > application called MPI_Abort(MPI_COMM_WORLD, 85) - process 0[unset]: > > aborting job: > > application called MPI_Abort(MPI_COMM_WORLD, 85) - process 0 > > I don't understand what I'm doing wrong. > > Respectfully, > > Adam > > On Wed, Jun 29, 2011 at 1:26 AM, Matthew Knepley <knepley at gmail.com> > > wrote: > >> > >> On Tue, Jun 28, 2011 at 10:20 PM, Adam Byrd <adam1.byrd at gmail.com> > >> wrote: > >>> > >>> Matt, > >>> > >>> Alright, that means I need to continue learning how to use > >>> MatSetValues(). With my 6x6 example I tried filling it with four 3x3 sub > >>> matrices, but when I do that I get the error 'sum of local sizes 12 does > >>> not > >>> equal global size.' I had 4 processors each calling MatSetValues for their > >>> own 3x3. Graphically, I arranged the nodes 0 1 > >>> > >>> 2 3 > >>> where process 0 had global rows 0-2 and global columns 0-2; process 1 had > >>> 0-2, 3-5; process 2 had 3-5, 0-2; and process 3 had 3-5, 3-5. >From the > >>> documentation, I think this should be correct, but I'm not sure. Also, > >>> which > >>> format would you recommend for storing the matrix? > >> > >> 1) With any error, send the Entire error message. > >> 2) PETSc matrices are divided by rows, not rows and columns, see the > >> manual section. Rows & columns only makes sense for dense matrices > >> 3) You can still set arbitrary blocks no matter how the matrix is divided > >> 4) The error means you tried to set both local and global dimensions, and > >> they do not add up correctly. Just set the global dimensions > >> Matt > >> > >>> > >>> Jack, > >>> > >>> I'm a summer intern just getting started with this project, so I don't > >>> know all the details yet (I can ask though). I know I need to find the > >>> Green's function which will involve the trace of the inverted Hamiltonian, > >>> as well as the rest of the matrix. I have inquired about avoiding the > >>> inversion altogether, but my instructor doesn't believe there is a way > >>> around it. Once I've worked through the math I want to explore other > >>> options > >>> though. > >>> > >>> Respectfully, > >>> Adam > >>> > >>> On Tue, Jun 28, 2011 at 6:08 PM, Matthew Knepley <knepley at gmail.com> > >>> wrote: > >>>> > >>>> On Tue, Jun 28, 2011 at 5:01 PM, Adam Byrd <adam1.byrd at gmail.com> > >>>> wrote: > >>>>> > >>>>> Actually, it's quite sparse. In the 3600x3600 there are only just 4 > >>>>> nonzero entries in each row. This means it's 99.9% empty. My smaller 6x6 > >>>>> example is dense, but it's only practice building and manipulating > >>>>> matrices. > >>>> > >>>> Ah, then its easy. Just call MatSetValues() with each block. Then use > >>>> MUMPS to do a sparse direct solve. > >>>> Matt > >>>> > >>>>> > >>>>> Respectfully, > >>>>> Adam > >>>>> > >>>>> On Tue, Jun 28, 2011 at 5:55 PM, Matthew Knepley <knepley at gmail.com> > >>>>> wrote: > >>>>>> > >>>>>> It sounds like you have a dense matrix (from your example). Is this > >>>>>> true? If so, you should use Elemental (on Google Code). > >>>>>> Thanks, > >>>>>> Matt > >>>>>> > >>>>>> On Tue, Jun 28, 2011 at 8:55 AM, Adam Byrd <adam1.byrd at gmail.com> > >>>>>> wrote: > >>>>>>> > >>>>>>> Hi, > >>>>>>> I'm rather new to PETSc and trying to work out the best way to create > >>>>>>> and fill a large sparse matrix distributed over many processors. > >>>>>>> Currently, > >>>>>>> my goal is to create a 3600x3600 matrix in units of 12x12 blocks with > >>>>>>> several blocks on any given node. I'd like to create the matrix in > >>>>>>> such a > >>>>>>> way that each node only holds the information in it's handful of > >>>>>>> blocks and > >>>>>>> not the entire matrix. Eventually, this matrix is to be inverted (I > >>>>>>> know, > >>>>>>> inversion should be avoided, but as this is a Hamiltonian matrix from > >>>>>>> which > >>>>>>> I need the Green's function, I'm unaware of a way to forgo carrying > >>>>>>> out the > >>>>>>> inversion). Additionally, the values will be changed slightly and the > >>>>>>> matrix > >>>>>>> will be repeatedly inverted. It's structure will remain the same. In > >>>>>>> order > >>>>>>> to learn how to do this is I am starting with a small 6x6 matrix > >>>>>>> broken into > >>>>>>> four 3x3 blocks and distributed one block per node. I've been able to > >>>>>>> create > >>>>>>> a local 3x3 matrix on each node, with it's own values, and with the > >>>>>>> global > >>>>>>> row/column IDs correctly set to [0, 1, 2] or [3, 4, 5] depending on > >>>>>>> where > >>>>>>> the block is in the matrix. My problem manifests when I try to create > >>>>>>> the > >>>>>>> larger matrix from the individual smaller ones. When the matrix is > >>>>>>> constructed I'm trying to use MatSetValues and having each node pass > >>>>>>> in it's > >>>>>>> 3x3 block. I end up with an error that the sum of local lengths 12x12 > >>>>>>> does > >>>>>>> not match the global length 6x6. It appears as though this is from > >>>>>>> passing > >>>>>>> in four 3x3s and the program interpreting that as a 12x12 instead of > >>>>>>> as a > >>>>>>> 6x6 with the blocks in a grid. > >>>>>>> My question is then: is it possible to fill a matrix as a grid of > >>>>>>> blocks, or can I only fill it in groups of rows or columns? Also, am I > >>>>>>> approaching this problem the correct way, or are there more efficient > >>>>>>> ways > >>>>>>> of building this matrix with the ultimate goal of inverting it? > >>>>>>> I have included my copy of a modified example if it helps. I do > >>>>>>> apologize if this is answered somewhere in the documentation, I have > >>>>>>> been > >>>>>>> unable to find a solution. > >>>>>>> Respectfully, > >>>>>>> Adam > >>>>>> > >>>>>> > >>>>>> -- > >>>>>> What most experimenters take for granted before they begin their > >>>>>> experiments is infinitely more interesting than any results to which > >>>>>> their > >>>>>> experiments lead. > >>>>>> -- Norbert Wiener > >>>>> > >>>> > >>>> > >>>> > >>>> -- > >>>> What most experimenters take for granted before they begin their > >>>> experiments is infinitely more interesting than any results to which > >>>> their > >>>> experiments lead. > >>>> -- Norbert Wiener > >>> > >> > >> > >> > >> -- > >> What most experimenters take for granted before they begin their > >> experiments is infinitely more interesting than any results to which their > >> experiments lead. > >> -- Norbert Wiener > > > > >
