> On 15 Sep 2020, at 5:40 PM, Abhyankar, Shrirang G > <shrirang.abhyan...@pnnl.gov> wrote: > > Pierre, > You are right. There are a few MatMultTransposeAdd that may need > conforming layouts for the equality/inequality constraint vectors and > equality/inequality constraint Jacobian matrices. I need to check if that’s > the case. We only have ex1 example currently, we need to add more examples. > We are currently working on making PDIPM robust and while doing it will work > on adding another example. > > Very naive question, but given that I have a single constraint, how do I > split a 1 x N matrix column-wise? I thought it was not possible. > > When setting the size of the constraint vector, you need to set the local > size on one rank to 1 and all others to zero. For the Jacobian, the local row > size on that rank will be 1 and all others to zero. The column layout for the > Jacobian should follow the layout for vector x. So each rank will set the > local column size of the Jacobian to local size of x.
That is assuming I don’t want x to follow the distribution of the Hessian, which is not my case. Is there some plan to make PDIPM handle different layouts? I hope I’m not the only one thinking that having a centralized Hessian when there is a single constraint is not scalable? Thanks, Pierre > Shri > >> On 15 Sep 2020, at 2:21 AM, Abhyankar, Shrirang G >> <shrirang.abhyan...@pnnl.gov <mailto:shrirang.abhyan...@pnnl.gov>> wrote: >> >> Hello Pierre, >> PDIPM works in parallel so you can have distributed Hessian, Jacobians, >> constraints, variables, gradients in any layout you want. If you are using >> a DM then you can have it generate the Hessian. > > Could you please show an example where this is the case? > pdipm->x, which I’m assuming is a working vector, is both used as input for > Hessian and Jacobian functions, e.g., > https://gitlab.com/petsc/petsc/-/blob/master/src/tao/constrained/impls/ipm/pdipm.c#L369 > > <https://gitlab.com/petsc/petsc/-/blob/master/src/tao/constrained/impls/ipm/pdipm.c#L369> > (Hessian) + > https://gitlab.com/petsc/petsc/-/blob/master/src/tao/constrained/impls/ipm/pdipm.c#L473 > > <https://gitlab.com/petsc/petsc/-/blob/master/src/tao/constrained/impls/ipm/pdipm.c#L473> > (Jacobian) > I thus doubt that it is possible to have different layouts? > In practice, I end up with the following error when I try this (2 processes, > distributed Hessian with centralized Jacobian): > [1]PETSC ERROR: --------------------- Error Message > -------------------------------------------------------------- > [1]PETSC ERROR: Nonconforming object sizes > [1]PETSC ERROR: Vector wrong size 14172 for scatter 0 (scatter reverse and > vector to != ctx from size) > [1]PETSC ERROR: #1 VecScatterBegin() line 96 in > /Users/jolivet/Documents/repositories/petsc/src/vec/vscat/interface/vscatfce.c > [1]PETSC ERROR: #2 MatMultTransposeAdd_MPIAIJ() line 1223 in > /Users/jolivet/Documents/repositories/petsc/src/mat/impls/aij/mpi/mpiaij.c > [1]PETSC ERROR: #3 MatMultTransposeAdd() line 2648 in > /Users/jolivet/Documents/repositories/petsc/src/mat/interface/matrix.c > [0]PETSC ERROR: Nonconforming object sizes > [0]PETSC ERROR: Vector wrong size 13790 for scatter 27962 (scatter reverse > and vector to != ctx from size) > [1]PETSC ERROR: #4 TaoSNESFunction_PDIPM() line 510 in > /Users/jolivet/Documents/repositories/petsc/src/tao/constrained/impls/ipm/pdipm.c > [0]PETSC ERROR: #5 TaoSolve_PDIPM() line 712 in > /Users/jolivet/Documents/repositories/petsc/src/tao/constrained/impls/ipm/pdipm.c > [1]PETSC ERROR: #6 TaoSolve() line 222 in > /Users/jolivet/Documents/repositories/petsc/src/tao/interface/taosolver.c > [0]PETSC ERROR: #1 VecScatterBegin() line 96 in > /Users/jolivet/Documents/repositories/petsc/src/vec/vscat/interface/vscatfce.c > [0]PETSC ERROR: #2 MatMultTransposeAdd_MPIAIJ() line 1223 in > /Users/jolivet/Documents/repositories/petsc/src/mat/impls/aij/mpi/mpiaij.c > [0]PETSC ERROR: #3 MatMultTransposeAdd() line 2648 in > /Users/jolivet/Documents/repositories/petsc/src/mat/interface/matrix.c > [0]PETSC ERROR: #4 TaoSNESFunction_PDIPM() line 510 in > /Users/jolivet/Documents/repositories/petsc/src/tao/constrained/impls/ipm/pdipm.c > [0]PETSC ERROR: #5 TaoSolve_PDIPM() line 712 in > /Users/jolivet/Documents/repositories/petsc/src/tao/constrained/impls/ipm/pdipm.c > [0]PETSC ERROR: #6 TaoSolve() line 222 in > /Users/jolivet/Documents/repositories/petsc/src/tao/interface/taosolver.c > > I think this can be reproduced by ex1.c by just distributing the Hessian > instead of having it centralized on rank 0. > > >> Ideally, you want to have the layout below to minimize movement of >> matrix/vector elements across ranks. >> · The layout of vectors x, bounds on x, and gradient is same. >> · The row layout of the equality/inequality Jacobian is same as the >> equality/inequality constraint vector layout. >> · The column layout of the equality/inequality Jacobian is same as >> that for x. > > Very naive question, but given that I have a single constraint, how do I > split a 1 x N matrix column-wise? I thought it was not possible. > > Thanks, > Pierre > > >> · The row and column layout for the Hessian is same as x. >> >> The tutorial example ex1 is extremely small (only 2 variables) so its >> implementation is very simplistic. I think, in parallel, it ships off >> constraints etc. to rank 0. It’s not an ideal example w.r.t demonstrating a >> parallel implementation. We aim to add more examples as we develop PDIPM. If >> you have an example to contribute then we would most welcome it and provide >> help on adding it. >> >> Thanks, >> Shri >> From: petsc-dev <petsc-dev-boun...@mcs.anl.gov >> <mailto:petsc-dev-boun...@mcs.anl.gov>> on behalf of Pierre Jolivet >> <pierre.joli...@enseeiht.fr <mailto:pierre.joli...@enseeiht.fr>> >> Date: Monday, September 14, 2020 at 1:52 PM >> To: PETSc Development <petsc-dev@mcs.anl.gov <mailto:petsc-dev@mcs.anl.gov>> >> Subject: [petsc-dev] PDIPDM questions >> >> Hello, >> In my quest to help users migrate from Ipopt to Tao, I’ve a new question. >> When looking at src/tao/constrained/tutorials/ex1.c, it seems that almost >> everything is centralized on rank 0 (local sizes are 0 but on rank 0). >> I’d like to have my Hessian distributed more naturally, as in (almost?) all >> other SNES/TS examples, but still keep the Jacobian of my equality >> constraint, which is of dimension 1 x N (N >> 1), centralized on rank 0. >> Is this possible? >> If not, is it possible to supply the transpose of the Jacobian, of dimension >> N x 1, which could then be distributed row-wise like the Hessian? >> Or maybe use some trick to distribute a MatAIJ/MatDense of dimension 1 x N >> column-wise? Use a MatNest with as many blocks as processes? >> >> So, just to sum up, how can I have a distributed Hessian with a Jacobian >> with a single row? >> >> Thanks in advance for your help, >> Pierre
