Hi, PETSc Developers<br><br>In parallel mode, I have 3 MPIDense matrices, A1, A2, A3. Now, I need to exact submatrices B1, B2, B3 in parallel mode from A1, A2, A3 respectively. I know I should use MatGetSubMatrix(). My problem is in <br>
<pre>MatGetSubMatrix(Mat mat,IS isrow,IS iscol,PetscInt csize,MatReuse cll,Mat *newmat)<br></pre>, the parameter "isrow" means "rows this processor should obtain". if Bi in some nodes (cpus) of the cluster (Ai have rows in them) don't have rows, is it work?<br>
<br>After getting Bi, I will create MPIDense-based C and combine them into C like<br><br> B1<br>C= B2<br> B3<br>MatGetRow();<br>MatSetValues() should work, right? <br><br>Could you give me some comments about these operations? thanks a lot. Happy new year!<br>
<br>Regards,<br>Yujie<br>