<div class="gmail_extra">On Wed, May 2, 2012 at 1:55 PM, TAY wee-beng <span dir="ltr"><<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Hi,<br>
<br>
I did a MatView and VecView on both C and Fortran, right after Mat
and Vec assembly. I have attached the printout below. They are
exactly the same, but yet the result is different in Neumann
condition. However, the dirichlet condition gives the correct ans.
Is there anything else that could be wrong even if the Mat and Vec
are the same?<br></div></blockquote><div><br></div><div>Did you set the null space for the matrix when you have Neumann conditions?</div><div><br></div><div> Matt</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Thanks!<br>
<br>
Fortran:<br>
<br>
Matrix Object: 1 MPI processes<br>
type: seqaij<br>
row 0: (0, 2) (1, -1) (3, -1)<br>
row 1: (0, -1) (1, 3) (2, -1) (4, -1)<br>
row 2: (1, -1) (2, 2) (5, -1)<br>
row 3: (0, -1) (3, 3) (4, -1) (6, -1)<br>
row 4: (1, -1) (3, -1) (4, 4) (5, -1) (7, -1)<br>
row 5: (2, -1) (4, -1) (5, 3) (8, -1)<br>
row 6: (3, -1) (6, 2) (7, -1)<br>
row 7: (4, -1) (6, -1) (7, 3) (8, -1)<br>
row 8: (5, -1) (7, -1) (8, 2)<br>
Vector Object:Vec_0000000084000000_0 1 MPI processes<br>
type: mpi<br>
Process [0]<br>
0.25<br>
0.0205213<br>
1.135e-005<br>
0.0205213<br>
0.00168449<br>
9.31663e-007<br>
1.135e-005<br>
9.31663e-007<br>
5.15289e-010<br>
Vector Object:Vec_0000000084000000_1 1 MPI processes<br>
type: mpi<br>
Process [0]<br>
0.14924<br>
0.0242397<br>
-0.0260347<br>
0.0242397<br>
-0.0256192<br>
-0.0400102<br>
-0.0260347<br>
-0.0400102<br>
-0.0400102<br>
Press any key to continue . . .<br>
<br>
C:<br>
<br>
Matrix Object: 1 MPI processes<br>
type: seqaij<br>
row 0: (0, 2) (1, -1) (3, -1) <br>
row 1: (0, -1) (1, 3) (2, -1) (4, -1) <br>
row 2: (1, -1) (2, 2) (5, -1) <br>
row 3: (0, -1) (3, 3) (4, -1) (6, -1) <br>
row 4: (1, -1) (3, -1) (4, 4) (5, -1) (7, -1) <br>
row 5: (2, -1) (4, -1) (5, 3) (8, -1) <br>
row 6: (3, -1) (6, 2) (7, -1) <br>
row 7: (4, -1) (6, -1) (7, 3) (8, -1) <br>
row 8: (5, -1) (7, -1) (8, 2) <br>
Vector Object:Vec_0x1d3b000_0 1 MPI processes<br>
type: mpi<br>
Process [0]<br>
0.25<br>
0.0205212<br>
1.135e-05<br>
0.0205212<br>
0.00168449<br>
9.31663e-07<br>
1.135e-05<br>
9.31663e-07<br>
5.15288e-10<br>
Vector Object:Vec_0x1d3b000_1 1 MPI processes<br>
type: mpi<br>
Process [0]<br>
0.139311<br>
0.0305751<br>
-0.0220633<br>
0.0305751<br>
-0.0135158<br>
-0.042185<br>
-0.0220633<br>
-0.042185<br>
-0.058449<br>
<br>
<br>
<br>
<pre cols="72">Yours sincerely,
TAY wee-beng</pre>
<br>
On 1/5/2012 11:54 PM, Matthew Knepley wrote:
<blockquote type="cite">
<div class="gmail_extra">On Tue, May 1, 2012 at 5:48 PM, TAY
wee-beng <span dir="ltr"><<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>></span>
wrote:<br>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
Do you mean my method is wrong?<br>
<br>
I am following the template of ex22f,<br>
<br>
where the variables are declared as :<br>
<br>
PetscScalar v(5)<br>
<br>
MatStencil row(4),col(4,5)<br>
<br>
Hence,<br>
<br>
for the neumann BC<br>
<br>
num = 1<br>
<br>
if (j/=0) then<br>
<br>
v(num) = -rho*HxdHy<br>
<br>
col(MatStencil_i,num) = i<br>
<br>
col(MatStencil_j,num) = j-1<br>
<br>
num = num + 1<br>
<br>
end if<br>
<br>
if (i/=0) then<br>
<br>
v(num) = -rho*HydHx<br>
<br>
col(MatStencil_i,num) = i-1<br>
<br>
col(MatStencil_j,num) = j<br>
<br>
num = num + 1<br>
<br>
end if<br>
<br>
if (i/=mx-1) then<br>
<br>
v(num) = -rho*HydHx<br>
<br>
col(MatStencil_i,num) = i+1<br>
<br>
col(MatStencil_j,num) = j<br>
<br>
num = num + 1<br>
<br>
end if<br>
<br>
if (j/=my-1) then<br>
<br>
v(num) = -rho*HxdHy<br>
<br>
col(MatStencil_i,num) = i<br>
<br>
col(MatStencil_j,num) = j+1<br>
<br>
num = num + 1<br>
<br>
end if<br>
<br>
v(num) = ((num-1)/2.0)*rho*(HxdHy + HydHx)<br>
<br>
print *, v<br>
<br>
col(MatStencil_i,num) = i<br>
<br>
col(MatStencil_j,num) = j<br>
<br>
!num = num + 1<br>
<br>
call MatSetValuesStencil(jac,i1,row,num,col,v,INSERT_VALUES,ierr)<br>
<br>
I do not get any more out of range error. However,my ans is
still different from that of ex29 in C.<br>
</blockquote>
<div><br>
</div>
<div>This is very simple. You have an error in your code.
Checking it is very simple: run the code and</div>
<div>break in MatSetValues(). Make sure ex29 makes calls with
exactly the same indices as your ex29f.</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Yours sincerely,<br>
<br>
TAY wee-beng<br>
</blockquote>
</div>
<div><br><span class="HOEnZb"><font color="#888888">
</font></span></div><span class="HOEnZb"><font color="#888888">
-- <br>
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to
which their experiments lead.<br>
-- Norbert Wiener<br>
</font></span></div>
</blockquote>
</div>
</blockquote></div><br><br clear="all"><div><br></div>-- <br>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>
-- Norbert Wiener<br>
</div>