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<div style=""> Hi, Petsc Team,<br>
<br>
The PETSC user manual says that the matrix format of block compressed row (BAIJ) will be more efficient than the default AIJ format for problems with multiple DOF. But the description of using BAIJ matrix is very limited in the manual. When trying to replace
AIJ with BAIJ in the code of iterative solver, I often meet the errors " No support for this operation for this object type!", " Matrix format mpibaij does not have a built-in PETSc direct solver! ". I think something must be missing here when we change the
format. <br>
<br>
And how to prelocate memory for BAIJ matrices when we have multiple DOF? Where can we find detailed statements or example codes of using BAIJ with preconditioners in iterative computation?<br>
<br>
BTW, When we use DA to organize the data for parallel computing, is it more natural to use DAGetMatrix() to create the matrix than using MatCreateMPIAIJ() ?
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<br>
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Thank you.<br>
<br>
<br>
Zhisong Li<br>
<br>
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