Thanks for early response Jed!,
>
>I fixed outer Krylov as PREONLY so it does not use any vectors (I guess).?
>Standard Vcycle includes 1 pre and 1 post smoothing.
>
>KSP-Richardson + PC-Jacobi are ingredients for pre-smoothing and? post
>smoothing.?
>To my understanding, 2 Vectors are used by KSP Richardson + 1 Vector is used
>by PC-Jacobi?
>at pre and post smoothing. This makes 6 vectors at each level and for 5
>levels, they should be 30!
>
>
>
>Do I think right ?
>
>Further hint to make PCMG more memory-efficient is appreciated.
>with warm regard, Abdul
>
>
>
>
>
>
>
>
>>________________________________
>> From: Jed Brown <jedbrown at mcs.anl.gov>
>>To: Abdul Hanan Sheikh <hanangul12 at yahoo.co.uk>; PETSc users list
>><petsc-users at mcs.anl.gov>
>>Sent: Thursday, 24 May 2012, 21:22
>>Subject: Re: [petsc-users] Multigrid Vcycle.
>>
>>
>>On Thu, May 24, 2012 at 2:14 PM, Abdul Hanan Sheikh <hanangul12 at
>>yahoo.co.uk> wrote:
>>
>>Dear all,
>>>
>>>I am quit beginner in PETSc.
>>>
>>>I wrote a code for multigrid Vcycle (as preconditioer) by following the
>>>instructions on manual page.
>>>
>>>I want to see how much memory a Vcycle allocates by default in terms of
>>>number of matrices and vectors.
>>>
>>>I made a try to see by comparing with jacobi preconditioner, which surely
>>>allocates 1 vector ONLY.
>>>
>>>It turns out that a VCycle for FIVE (5) levels including coarsest level
>>>allocates memory for 53 vectors and
>>>
>>>subsequently it destroys too.
>>
>>
>>Some of those vectors are very small due to being on the coarse level. There
>>are also the vectors used by the outer Krylov method.
>>?
>>
>>>
>>>Is it normal ??
>>>
>>>
>>>
>>>
>>>
>>>Thanks in advance,
>>>
>>>Abdul
>>>
>>
>>
>>
>
>
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