[petsc-users] Transpose of Block Matrix with aij type

[Choi240]

Hi,

I have to compute multiplication between two block matrices. It should be as follows:

B1 | B2         A1        B1A1+B2A2
----------   *   ---   =   ---------------
B3 | B4         A2        B3A1+B4A2

However, I just have A =  [A1 A2]. So, I need to get A^T. Is there a way I can get the transpose of this block matrix with the MatTranspose()? Or do I have to use another function such as MatGetSubMatrices()?

Thank you,
Joon

-------- Original message --------
Subject: Re: [petsc-users] Transpose of Block Matrix with aij type 
From: Karl Rupp <rupp at mcs.anl.gov> 
To: petsc-users at mcs.anl.gov 
CC: choi240 at purdue.edu 

Hi,

why would you expect that the transpose of a 3x8 matrix is not a 8x3-matrix?

Best regards,
Karli


On 04/23/2013 03:27 PM, Joon hee Choi wrote:
> Hello,
>
> I tried to get transpose of block matrix(just with aij type), but the result was not a block matrix. For example,
>
> A =
> 1 2 3 4 | 4 3 2 1
> 2 3 4 5 | 5 4 3 2
> 3 4 5 6 | 6 5 4 3
>
>
> AT(expected) =
> 1 2 3 4
> 2 3 4 5
> 3 4 5 6
> -------
> 4 3 2 1
> 5 4 3 2
> 6 5 4 3
>
>
> AT(result) =
> 1 2 3
> 2 3 4
> 3 4 5
> 4 5 6
> 4 5 6
> 3 4 5
> 2 3 4
> 1 2 3
>
> If someone knows about this problem, please let me know it.
>
> Thank you
>
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