how to get the transpose of a block sparsity matrix?

[hua zhang]

Dear all deal.ii users,

        I am studying goal oriented adaptivity for FSI problems and code it in deal.ii. The system consists of velocity, pressure, displacement(u,p,w), so  I use block sparsity matrix for system matrix. When I solve the dual equation, I find what I need is a transpose matrix of system matrix, so how should I do to get the transpose of block sparsity matrix?

        I have tried to get transpose of every block using transpose_operator, but I don't know how to combined these terms into a new block sparsity matrix.

[Wolfgang Bangerth]

In essence, you only need an object whose vmult function calls the Tvmult
function of your block sparse matrix. That can be achieved with only a few
lines of code. But I think it can be done in an even easier way: create a
LinearOperator object from your block matrix, and then apply transpose() to it
to get the transpose linear operator.

Best
W.

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Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[hua zhang]

Thank you very much, Prof.Bangerth. I have solved this problem using the first way you mentioned.
在 2019年8月18日星期日 UTC+8上午5:33:26，Wolfgang Bangerth写道：