Community
cancel
Showing results for
Did you mean:
Beginner
78 Views

## pardiso boundary condition

hi,
i am using PARDISO to solve Ax=b type unsymmetric real sparse matrix. For the give problem if i set boundary conditions as pressure gradient = 0 then PARDISO gives result same as other solvers, but if i set BC's as p=0 then PARDISO gives different(wrong) result as compared to other solvers.
5 Replies
Employee
78 Views
Hi,
What differential equation you are solve? Is "p = 0" Dirichle or Neumann boundary condition?
With best regards,
Beginner
78 Views
hi,
it is Dirichlet
Employee
78 Views
Hi,
What about equation? Could determinant ofresult stiffness matrix is equal zero? If not, could you please attach testcase here?
With best regards,
Beginner
78 Views
hi,
no the determinant is not zero. The problem looks like (actual problem is large this is an example)
 AP11 AE11 0 0 AN11 0 0 0 0 0 0 0 X1 B1 AW21 AP21 AE21 0 0 AN21 0 0 0 0 0 0 X2 B2 0 AW31 AP31 AE31 0 0 AN31 0 0 0 0 0 X3 B3 0 0 AW41 AP41 0 0 0 AN41 0 0 0 0 X4 B4 AS12 0 0 0 AP12 AE12 0 0 AN12 0 0 0 X5 B5 0 AS22 0 0 AW22 AP22 AE22 0 0 AN22 0 0 X X6 = B6 0 0 AS32 0 0 AW32 AP32 AE32 0 0 AN32 0 X7 B7 0 0 0 AS42 0 0 AW42 AP42 0 0 0 AN42 X8 B8 0 0 0 0 AS13 0 0 0 AP13 AE13 0 0 X9 B9 0 0 0 0 0 AS23 0 0 AW23 AP23 AE23 0 X10 B10 0 0 0 0 0 0 AS33 0 0 AW33 AP33 AE33 X11 B11 0 0 0 0 0 0 0 AS42 0 0 AW43 AP43 X12 B12

THIS IS COEFFICIENT MATRIX OF A 4x3 MATRIX.
in order to set right boundary as x=0 (Dirichlet) what i need to do is to set AE41,AE42,AE43 as zero. But when i do this and run PARDISO it gives wrong results (I solved it with gauss siedel and it gives correct result).
Matrix looks like
 11 21 31 41 12 22 32 42 13 23 33 43
Employee
78 Views
Hi,
Unfortunately, I couldn't find AE41, AE42 and AE43 in table of symbols you wrote. But in my opinion if one want to set Dirichlet boundary condition in some point he need to set zero in correspondent column/string of matrix and change correspondent diagonal element. Nevertheless, could you provide testcase that I could compile and execute for deeper investigation of problem?
With best regards,