[Trilinos-Users] [EXTERNAL] Why does Anasazi bail out early?

[Baker, Christopher G.]

Maximum restarts (effectively, maximum iterations) will make it stop. Try increasing it and seeing if the number of iterations before termination increases.

-----Original Message-----
From: Nico Schlömer [nico.schloemer at gmail.com<mailto:nico.schloemer at gmail.com>]
Sent: Monday, August 20, 2012 07:56 PM Eastern Standard Time
To: Baker, Christopher G.
Cc: Thornquist, Heidi K; trilinos-users at software.sandia.gov
Subject: Re: [Trilinos-Users] [EXTERNAL] Why does Anasazi bail out early?


Unset, so I supposed it'd take a sane default. Setting

MyPL.set("Maximum Restarts", 10);

yields a similar result: Still no indication of what criterion made
the iteration stop.




On Tue, Aug 21, 2012 at 1:48 AM, Baker, Christopher G. <bakercg at ornl.gov> wrote:
> How about "Num Restarts"?
>
>
> -----Original Message-----
> From: Nico Schlömer [nico.schloemer at gmail.com]
> Sent: Monday, August 20, 2012 07:43 PM Eastern Standard Time
> To: Thornquist, Heidi K
> Cc: trilinos-users at software.sandia.gov
> Subject: Re: [Trilinos-Users] [EXTERNAL] Why does Anasazi bail out early?
>
> Yep, I'll definitely look at operator transformations, but first I
> wanted to make that the code works as it is. My main problem right now
> is the fact that I can deduct little to nothing about what went wrong
> from the bare logs.
> The parameters I used are
>
> MyProblem->setHermitian(true);
> MyProblem->setNEV(10);
>
> MyPL.set("Which", "LM");
> MyPL.set("Block Size", 2);
> MyPL.set("Num Blocks", 10);
> MyPL.set("Convergence Tolerance", 1.0e-5);
>
> The log file is attached.
>
> --Nico
>
>
>
> On Tue, Aug 21, 2012 at 1:14 AM, Thornquist, Heidi K <hkthorn at sandia.gov>
> wrote:
>> Hi Nico,
>>
>> What are the parameters that you are passing block Krylov-Schur?
>>
>> This type of solver will have a hard time computing the smallest magnitude
>> eigenvalues without a spectral transformation, like shift-invert or Cayley.
>> It looks like you are using one since the Ritz values are being printed out
>> with the largest magnitude first, so what are you using and what is the
>> shift?  It looks like you set the eigenproblem as Hermitian (since the
>> output is not printing out any imaginary part of the eigenvalue).  You might
>> consider using block Davidson or LOBPCG for your problem instead since they
>> can more easily find the smallest eigenvalues.
>>
>> If you want to send me a log of the output you receive using all those
>> verbosity flags, that would also help.
>>
>> Thanks,
>> Heidi
>>
>>
>> ________________________________________
>> From: trilinos-users-bounces at software.sandia.gov
>> [trilinos-users-bounces at software.sandia.gov] on behalf of Nico Schlömer
>> [nico.schloemer at gmail.com]
>> Sent: Monday, August 20, 2012 5:02 PM
>> To: trilinos-users at software.sandia.gov
>> Subject: [EXTERNAL] [Trilinos-Users] Why does Anasazi bail out early?
>>
>> Hi,
>>
>> I'm trying to use Anasazi for computing a bunch of SM eigenvalues, and
>> while things compile and run fine, the iterations always aborts
>> prematurely without indicating what went wrong. If the tolerance is,
>> say, 1.0e-15, a typical last block of output (with verbosity
>> Anasazi::IterationDetails + Anasazi::Errors + Anasazi::Warnings +
>> Anasazi::StatusTestDetails + Anasazi::Debug + Anasazi::FinalSummary)
>> would be
>>
>> =========================== *snip* ===========================
>>
>>                          BlockKrylovSchur Solver Status
>>
>> The solver is initialized.
>> The number of iterations performed is 110
>> The block size is         2
>> The number of blocks is   10
>> The current basis size is 20
>> The number of auxiliary vectors is 0
>> The number of operations Op*x   is 220
>>
>> CURRENT RITZ VALUES
>>           Ritz Value       Ritz Residual
>>
>> --------------------------------------------------------------------------------
>>         8.075243e+00        5.120182e-04
>>         8.063177e+00        4.056698e-04
>>         8.063150e+00        3.596635e-03
>>         8.050790e+00        1.081923e-02
>>         8.042772e+00        9.878716e-03
>>         8.027045e+00        4.533151e-02
>>         8.015636e+00        4.997743e-02
>>         8.014430e+00        1.482199e-02
>>         7.983605e+00        6.111459e-02
>>         7.963543e+00        5.082745e-02
>>
>> Returning 0 eigenpairs to eigenproblem.
>> =========================== *snap* ===========================
>>
>> Note how the tolerance isn't met.
>> How can I find out what's going on?
>>
>> Cheers,
>> Nico
>>
>> _______________________________________________
>> Trilinos-Users mailing list
>> Trilinos-Users at software.sandia.gov
>> http://software.sandia.gov/mailman/listinfo/trilinos-users
>>
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