<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
I only have one field "names vx" and this variable change in both x and y directions. I have also chosen dof in DMDACreate2d to "1".
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
I am not sure why I should have aF[i][j].vx. "i" defines the grids in x direction and "j" is in y-directions. In all my previous codes I define" aF[j][i].vx" and not "aF[i][j].vx", and it was working properly.</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Best,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Sepideh<br>
</div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Jed Brown <jed@jedbrown.org><br>
<b>Sent:</b> Wednesday, February 3, 2021 11:46 AM<br>
<b>To:</b> Sepideh Kavousi <skavou1@lsu.edu>; petsc-users@mcs.anl.gov <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] SNES-norm is zero all the time</font>
<div> </div>
</div>
<div class="BodyFragment"><font size="2"><span style="font-size:11pt;">
<div class="PlainText">Sepideh Kavousi <skavou1@lsu.edu> writes:<br>
<br>
> I am not running an specific example. Attached is my code. and when I wun with<br>
> ./step5.out -snes_monitor -snes_fd_color -ts_monitor -snes_converged_reason -pc_type lu<br>
><br>
> it seems it does not solve anything because the output is like:<br>
><br>
> 0 SNES Function norm 0.000000000000e+00<br>
> Nonlinear solve converged due to CONVERGED_FNORM_ABS iterations 0<br>
> 1 TS dt 0.005 time 0.005<br>
<br>
Check your FormFunction for why af[][] is zero. I see<br>
<br>
aF[j][j].vx<br>
<br>
but you'll need to set at all the grid points, i.e., aF[j][i].vx and aF[j][i].vy.<br>
</div>
</span></font></div>
</body>
</html>