[petsc-users] Tao iterations
Jason Sarich
jason.sarich at gmail.com
Tue Apr 21 09:52:32 CDT 2015
Hi Justin,
blmvm believes that it is already sufficiently close to a minimum, so it
doesn't do anything. You may need to tighten some of the tolerance to force
an iteration.
Jason
On Tue, Apr 21, 2015 at 9:48 AM, Justin Chang <jychang48 at gmail.com> wrote:
> Time step 1:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0663148
> Objective value=-55.5945
> total number of iterations=35, (max: 2000)
> total number of function/gradient evaluations=37, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 2:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0682307
> Objective value=-66.9675
> total number of iterations=23, (max: 2000)
> total number of function/gradient evaluations=25, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 3:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0680522
> Objective value=-71.8211
> total number of iterations=19, (max: 2000)
> total number of function/gradient evaluations=22, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 4:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0551556
> Objective value=-75.1252
> total number of iterations=18, (max: 2000)
> total number of function/gradient evaluations=20, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 5:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0675667
> Objective value=-77.4414
> total number of iterations=6, (max: 2000)
> total number of function/gradient evaluations=8, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 6:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.059143
> Objective value=-79.5007
> total number of iterations=3, (max: 2000)
> total number of function/gradient evaluations=5, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 7:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0433683
> Objective value=-81.3546
> total number of iterations=5, (max: 2000)
> total number of function/gradient evaluations=8, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 8:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0840676
> Objective value=-82.9382
> total number of iterations=0, (max: 2000)
> total number of function/gradient evaluations=1, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 9:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0840676
> Objective value=-82.9382
> total number of iterations=0, (max: 2000)
> total number of function/gradient evaluations=1, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
> Time step 10:
>
> Tao Object: 1 MPI processes
> type: blmvm
> Gradient steps: 0
> TaoLineSearch Object: 1 MPI processes
> type: more-thuente
> Active Set subset type: subvec
> convergence tolerances: fatol=0.0001, frtol=0.0001
> convergence tolerances: gatol=0, steptol=0, gttol=0
> Residual in Function/Gradient:=0.0840676
> Objective value=-82.9382
> total number of iterations=0, (max: 2000)
> total number of function/gradient evaluations=1, (max: 4000)
> Solution converged: estimated |f(x)-f(X*)|/|f(X*)| <= frtol
>
>
>
>
>
> On Tue, Apr 21, 2015 at 9:28 AM, Jason Sarich <jason.sarich at gmail.com>
> wrote:
>
>> Hi Justin,
>>
>> what reason is blmvm giving for stopping the solve? (you can use
>> -tao_view or -tao_converged_reason to get this)
>>
>> Jason
>>
>> On Mon, Apr 20, 2015 at 6:32 PM, Justin Chang <jychang48 at gmail.com>
>> wrote:
>>
>>> Jason,
>>>
>>> I am using TaoGetSolutionStatus(tao,&its, ...) and it gives me exactly
>>> what I want. However, I seem to be having an issue with blmvm
>>>
>>> I wrote my own backward euler code for a transient linear diffusion
>>> problem with lower bounds >= 0 and upper bounds <= 1. For the first several
>>> time steps I am getting its > 0, and it decreases over time due to the
>>> nature of the discrete maximum principles. However, at some point my its
>>> become 0 and the solution does not "update", which seems to me that
>>> TaoSolve is not doing anything after that. This doesn't happen if I were to
>>> use tron (my KSP and PC are cg and jacobi respectively).
>>>
>>> Do you know why this behavior may occur?
>>>
>>> Thanks,
>>>
>>> On Tue, Apr 14, 2015 at 9:35 AM, Jason Sarich <jason.sarich at gmail.com>
>>> wrote:
>>>
>>>> Hi Justin,
>>>>
>>>> I have pushed these changes to the "next" branch, your code snippet
>>>> should work fine there.
>>>>
>>>> Note that there is also available (since version 3.5.0) the routine
>>>> TaoGetSolutionStatus(tao,&its,NULL,NULL,NULL,NULL,NULL) which will provide
>>>> the
>>>> same information
>>>>
>>>> Jason
>>>>
>>>> On Fri, Apr 10, 2015 at 6:28 PM, Justin Chang <jychang48 at gmail.com>
>>>> wrote:
>>>>
>>>>> Whatever is convenient and/or follow the "PETSc" standards.
>>>>> Something similar to SNESGetIterationNumber() or KSPGetIterationNumber()
>>>>> would be nice. Ideally I want my code to look like this:
>>>>>
>>>>> ierr = TaoGetIterationNumber(tao,&its);CHKERRQ(ierr);
>>>>> ierr = PetscPrintf(PETSC_COMM_WORLD, "Number of Tao iterations =
>>>>> %D\n", its);
>>>>>
>>>>> Thanks :)
>>>>>
>>>>> On Fri, Apr 10, 2015 at 5:53 PM, Jason Sarich <jason.sarich at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi Justin, I'll get this in. I assume that displaying the number of
>>>>>> iterations with tao_converged_reason is what you are asking for in
>>>>>> particular? Or did you have something else in mind?
>>>>>>
>>>>>> Jason
>>>>>> On Apr 10, 2015 16:42, "Smith, Barry F." <bsmith at mcs.anl.gov> wrote:
>>>>>>
>>>>>>>
>>>>>>> Justin,
>>>>>>>
>>>>>>> Sorry TAO simply doesn't even collect this information
>>>>>>> currently. But yes we should definitely make it available!
>>>>>>>
>>>>>>> Jason,
>>>>>>>
>>>>>>> Could you please add this; almost all the TaoSolve_xxx() have a
>>>>>>> local variable iter; change that to tao->niter (I'm guess this is suppose
>>>>>>> to capture this information) and add a TaoGetIterationNumber() and the uses
>>>>>>> can access this. Also modify at the end of TaoSolve() -tao_converged_reason
>>>>>>> to also print the iteration count. At the same time since you add this you
>>>>>>> can add a tao->totalits which would accumulate all iterations over all the
>>>>>>> solves for that Tao object and the routine TaoGetTotalIterations() to
>>>>>>> access this. Note that TaoSolve() would initialize tao->niter = 0 at the
>>>>>>> top.
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>> Barry
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> > On Apr 10, 2015, at 4:16 PM, Justin Chang <jchang27 at uh.edu> wrote:
>>>>>>> >
>>>>>>> > Hi all,
>>>>>>> >
>>>>>>> > Is there a way to generically obtain the number of Tao iterations?
>>>>>>> I am looking through the -help options for Tao and I don't see any metric
>>>>>>> where you can output this quantity in the manner that you could for SNES or
>>>>>>> KSP solves. I am currently using blmvm and tron, and the only way I can see
>>>>>>> getting this metric is by outputting -tao_view and/or -tao_monitor and
>>>>>>> manually finding this number. I find this cumbersome especially for
>>>>>>> transient problems where I would like to simply have this number printed
>>>>>>> for each step instead of ending up with unnecessary info.
>>>>>>> >
>>>>>>> > Thanks,
>>>>>>> >
>>>>>>> >
>>>>>>> > --
>>>>>>> > Justin Chang
>>>>>>> > PhD Candidate, Civil Engineering - Computational Sciences
>>>>>>> > University of Houston, Department of Civil and Environmental
>>>>>>> Engineering
>>>>>>> > Houston, TX 77004
>>>>>>> > (512) 963-3262
>>>>>>>
>>>>>>>
>>>>>
>>>>
>>>
>>
>
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