[petsc-users] How to pass the parameters for KSP

[vedaprakash subramanian]

Can anyone tell me whether the concept I understood is correct or not.

If I am having a MATLAB function func(Matrix A, Vector x, Vector b, Matrix
Q, Matrix M, int max_it, int tol, Vec* sol, int* err, int* iter, int* flag)
  to be converted into a KSP solver, then I have to do these following
steps.

1. In KSPSetUp_func(KSP ksp), initialize  KSPDefaultGetWork(ksp,11);  //
This tells the KSP that it is going to take 11 arguments
2. In KSPSolve_func(KSP ksp), declare
    Mat A, Q, M;
    Vec x, b, *sol;
    PetscInt max_it, *flag, *iter;
    PetscScalar tol, *err;

    A  = ksp->work[0];
    x   = ksp->work[1];
    b   = ksp->work[2];
    Q  = ksp->work[3];
    M   = ksp->work[4];
    max_it   = ksp->work[5];
    tol  = ksp->work[6];
    *sol   = ksp->work[7];
    *err   = ksp->work[8];
    *iter   = ksp->work[9];
    *flag   = ksp->work[10];

------------------------------
Is the above said is correct. Is that the way to get the arguments of the
KSPSolve.

Moreover, I have a doubt. What are these variables that are been used in
cg.c

  stored_max_it = ksp->max_it;
  X             = ksp->vec_sol;
  B             = ksp->vec_rhs;

Where are these variables (ksp->max_it, ksp->vec_sol and ksp->vec_rhs)
getting initialized.

-Vedaprakash

On Wed, Oct 6, 2010 at 7:56 PM, vedaprakash subramanian <
vedaprakashsubramanian at gmail.com> wrote:

> I need my KSP to take in Tolerence, flag, err, 3 matrices, right hand side
> vector. How can I make it to take all the parameters.
>
> On Mon, Sep 20, 2010 at 11:00 AM, <petsc-users-request at mcs.anl.gov> wrote:
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>>   1.  How to pass the parameters for KSP (vedaprakash subramanian)
>>   2. Re:  How to pass the parameters for KSP (Barry Smith)
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>> ----------------------------------------------------------------------
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>> Message: 1
>> Date: Sun, 19 Sep 2010 19:05:48 -0600
>> From: vedaprakash subramanian <vedaprakashsubramanian at gmail.com>
>> Subject: [petsc-users] How to pass the parameters for KSP
>> To: petsc-users at mcs.anl.gov
>> Message-ID:
>>        <AANLkTinjiGMTMVB1yVx6JEvPhjGi_=T+QY6HK7wnHgOa at mail.gmail.com<T%2BQY6HK7wnHgOa at mail.gmail.com>
>> >
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> I am converting a MATLAB function into a KSP solver. I am doing it similar
>> to BiCGStab. But I wanted to know how to pass the arguments of the
>> function
>> into KSP solver.
>>
>> Thanks,
>> Vedaprakash
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>> ------------------------------
>>
>> Message: 2
>> Date: Sun, 19 Sep 2010 21:49:47 -0500
>> From: Barry Smith <bsmith at mcs.anl.gov>
>> Subject: Re: [petsc-users] How to pass the parameters for KSP
>> To: PETSc users list <petsc-users at mcs.anl.gov>
>> Message-ID: <27B820EF-3A6A-424B-8A43-2A43E82089B3 at mcs.anl.gov>
>> Content-Type: text/plain; charset=us-ascii
>>
>>
>>  What arguments? Do you mean the right hand side x and the matrix? Or do
>> you mean parameters like the relative tolerance in convergence?
>>
>>  See src/ksp/ksp/examples/tutorials/ex1.c for a simple example.
>>
>>   Barry
>>
>> On Sep 19, 2010, at 8:05 PM, vedaprakash subramanian wrote:
>>
>> > I am converting a MATLAB function into a KSP solver. I am doing it
>> similar to BiCGStab. But I wanted to know how to pass the arguments of the
>> function into KSP solver.
>> >
>> > Thanks,
>> > Vedaprakash
>>
>>
>>
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