Re: [petsc-users] TimeStepper norm problems. EMIL Please read this
The more adaptors the better > On Apr 15, 2015, at 8:51 PM, Emil Constantinescu wrote: > > > On 3/24/15 5:31 AM, Lisandro Dalcin wrote: >> Emil, is there any chance you can try my code with your problem? I >> really need some feedback to push this to PETSc, otherwise > > Hi Lisandro - we checked ts_alpha_adapt and we tested it on a small system > (mildly stiff van der Pol ODE). I enclosed a Figure generated by Debo that > compares the error at the final time against ATOL - there alpha is the > original one (with original adaptor). For this problem your adaptor works > better [ error should be close to ATOL]. So from my perspective, your adaptor > works well. However, we need to keep the old too so that we have a one step > adaptor available ... since alpha is a one step method. > > Emil >
Re: [petsc-users] TimeStepper norm problems. EMIL Please read this
On 3/24/15 5:31 AM, Lisandro Dalcin wrote: Emil, is there any chance you can try my code with your problem? I really need some feedback to push this to PETSc, otherwise Hi Lisandro - we checked ts_alpha_adapt and we tested it on a small system (mildly stiff van der Pol ODE). I enclosed a Figure generated by Debo that compares the error at the final time against ATOL - there alpha is the original one (with original adaptor). For this problem your adaptor works better [ error should be close to ATOL]. So from my perspective, your adaptor works well. However, we need to keep the old too so that we have a one step adaptor available ... since alpha is a one step method. Emil Figure2.pdf Description: application/binary
Re: [petsc-users] Time integrated adjoints
On 4/15/15 12:37 PM, Barry Smith wrote:
Hong and Emil,
You will need to answer this.
On Apr 15, 2015, at 6:24 AM, Dave Makhija wrote:
Barry,
Is the method exact if I have a time dependent mass matrix (dF/dU_t changes
each time step)? I'm not sure it's possible if TSSetIJacobian expects a
function which computes the combination of dF/dU and a*dF/dU_t. But, perhaps
there is something I'm missing.
In the adjoint derivation, we assumed that we have F = M U_t - f(t,U);
so a*dF/dU_t is a*M, which holds if M=M(t). So in principle it should
work. However, because M(t_n) and M(t_{n+1}) are different, the adjoint
implementation might be slightly inconsistent -- and I'm saying this out
of caution. We did not test it on problems with M=M(t). Do you have such
an example interfaced with PETSc we can try?
Emil
Otherwise, it looks very comprehensive. I like how you added the "cost
integrand". If I recall correctly, the Trilinos package Rythmos is missing this.
Thanks!
Dave
On Tue, Apr 14, 2015 at 8:30 AM, Barry Smith wrote:
On Apr 14, 2015, at 1:06 AM, Dave Makhija wrote:
Hello,
I'm evaluating my options for computing time dependent adjoints. I did not think PETSc
supported this, but I see "TSAdjointSolve" in the development branch. That
would be fantastic news if you plan to support time integrated adjoints!
What features are envisioned and when is the targeted release date?
Dave,
We currently have discrete adjoint computations for explicit RK methods and
for implicit theta methods (backward Euler and Crank-Nicholson). The
development copy of the users manual has some discussion
(http://www.mcs.anl.gov/petsc/petsc-master/docs/manual.pdf page 135) and there
are several examples. I urge you to try them out now in master and stay in
contact with us to insure we provide what you need as we are actively
developing them.
We plan a release for early June.
Barry
Thanks!
Dave
Re: [petsc-users] Time integrated adjoints
Hong and Emil, You will need to answer this. > On Apr 15, 2015, at 6:24 AM, Dave Makhija wrote: > > Barry, > > Is the method exact if I have a time dependent mass matrix (dF/dU_t changes > each time step)? I'm not sure it's possible if TSSetIJacobian expects a > function which computes the combination of dF/dU and a*dF/dU_t. But, perhaps > there is something I'm missing. > > Otherwise, it looks very comprehensive. I like how you added the "cost > integrand". If I recall correctly, the Trilinos package Rythmos is missing > this. > > Thanks! > > Dave > > On Tue, Apr 14, 2015 at 8:30 AM, Barry Smith wrote: > > > On Apr 14, 2015, at 1:06 AM, Dave Makhija wrote: > > > > Hello, > > > > I'm evaluating my options for computing time dependent adjoints. I did not > > think PETSc supported this, but I see "TSAdjointSolve" in the development > > branch. That would be fantastic news if you plan to support time integrated > > adjoints! > > > > What features are envisioned and when is the targeted release date? > > Dave, > >We currently have discrete adjoint computations for explicit RK methods > and for implicit theta methods (backward Euler and Crank-Nicholson). The > development copy of the users manual has some discussion > (http://www.mcs.anl.gov/petsc/petsc-master/docs/manual.pdf page 135) and > there are several examples. I urge you to try them out now in master and > stay in contact with us to insure we provide what you need as we are actively > developing them. > We plan a release for early June. > > Barry > > > > > Thanks! > > > > Dave > >
Re: [petsc-users] petsc4py and mumps (or other direct sparse solver)
On 15 April 2015 at 18:15, Hong wrote:
> Benoit :
>
> mumps options can be called from PETSc C-code as
> ierr = PetscOptionsInsertString("-mat_mumps_icntl_13 1 -mat_mumps_icntl_24 1
> -mat_mumps_cntl_3 1e-12");CHKERRQ(ierr);
>
> or see petsc/src/ksp/ksp/examples/tutorials/ex52.c
>
> I do not know how to translate these calls into python API though.
>
opts = PETSc.Options() # dict-like
opts["mat_mumps_icntl_13"] = 1
opts["mat_mumps_icntl_24"] = 1
opts["mat_mumps_cntl_3"] = 1e-12
Or also:
opts = PETSc.Options()
opts.prefixPush("mat_mumps_")
opts["icntl_13"] = 1
opts["icntl_24"] = 1
opts["cntl_3"] = 1e-12
opts.prefixPop()
Or also:
opts = PETSc.Options("mat_mumps_")
opts["icntl_13"] = 1
opts["icntl_24"] = 1
opts["cntl_3"] = 1e-12
--
Lisandro Dalcin
Research Scientist
Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
Numerical Porous Media Center (NumPor)
King Abdullah University of Science and Technology (KAUST)
http://numpor.kaust.edu.sa/
4700 King Abdullah University of Science and Technology
al-Khawarizmi Bldg (Bldg 1), Office # 4332
Thuwal 23955-6900, Kingdom of Saudi Arabia
http://www.kaust.edu.sa
Office Phone: +966 12 808-0459
Re: [petsc-users] petsc4py and mumps (or other direct sparse solver)
Benoit :
mumps options can be called from PETSc C-code as
ierr = PetscOptionsInsertString("-mat_mumps_icntl_13 1 -mat_mumps_icntl_24
1 -mat_mumps_cntl_3 1e-12");CHKERRQ(ierr);
or see petsc/src/ksp/ksp/examples/tutorials/ex52.c
I do not know how to translate these calls into python API though.
Hong
Dear petsc-users,
>
> I am a beginner in petsc and I have some question with the python
> interface. I am trying to solve problem with mumps (or other direct sparse
> solver)
>
> I have written the following piece of code
>
> ksp = PETSc.KSP()
> ksp.create(PETSc.COMM_WORLD)
> ksp.setOperators(A)
> ksp.setType('preonly')
> pc=ksp.getPC()
> pc.setType('lu')
> pc.setFactorSolverPackage('mumps')
>
> It seems to works, however I have 2 questions
> 1/ how to set the Icntl parameters of mumps ? I didn't find the function
> MatMumpsSetIcntl.
> 2/ Is this piece of code right or written in good petsc style ?
>
> thanks a lot,
>
> Benoit
>
>
[petsc-users] petsc4py and mumps (or other direct sparse solver)
Dear petsc-users,
I am a beginner in petsc and I have some question with the python interface. I
am trying to solve problem with mumps (or other direct sparse solver)
I have written the following piece of code
ksp = PETSc.KSP()
ksp.create(PETSc.COMM_WORLD)
ksp.setOperators(A)
ksp.setType('preonly')
pc=ksp.getPC()
pc.setType('lu')
pc.setFactorSolverPackage('mumps')
It seems to works, however I have 2 questions
1/ how to set the Icntl parameters of mumps ? I didn't find the function
MatMumpsSetIcntl.
2/ Is this piece of code right or written in good petsc style ?
thanks a lot,
Benoit
Re: [petsc-users] Time integrated adjoints
Barry, Is the method exact if I have a time dependent mass matrix (dF/dU_t changes each time step)? I'm not sure it's possible if TSSetIJacobian expects a function which computes the combination of dF/dU and a*dF/dU_t. But, perhaps there is something I'm missing. Otherwise, it looks very comprehensive. I like how you added the "cost integrand". If I recall correctly, the Trilinos package Rythmos is missing this. Thanks! Dave On Tue, Apr 14, 2015 at 8:30 AM, Barry Smith wrote: > > > On Apr 14, 2015, at 1:06 AM, Dave Makhija wrote: > > > > Hello, > > > > I'm evaluating my options for computing time dependent adjoints. I did > not think PETSc supported this, but I see "TSAdjointSolve" in the > development branch. That would be fantastic news if you plan to support > time integrated adjoints! > > > > What features are envisioned and when is the targeted release date? > > Dave, > >We currently have discrete adjoint computations for explicit RK methods > and for implicit theta methods (backward Euler and Crank-Nicholson). The > development copy of the users manual has some discussion ( > http://www.mcs.anl.gov/petsc/petsc-master/docs/manual.pdf page 135) and > there are several examples. I urge you to try them out now in master and > stay in contact with us to insure we provide what you need as we are > actively developing them. > We plan a release for early June. > > Barry > > > > > Thanks! > > > > Dave > >
