Send all the output of 'make test' along with configure.log and make.log to <a href="mailto:petsc-maint@mcs.anl.gov">petsc-maint@mcs.anl.gov</a><div><br></div><div> Matt<br><br><div class="gmail_quote">On Mon, Feb 21, 2011 at 9:12 AM, Hung Thanh Nguyen <span dir="ltr"><<a href="mailto:hung.thanh.nguyen@petrell.no">hung.thanh.nguyen@petrell.no</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hi Pets use<br>
I just install Pets on Windows (I am using C compiler and ITL MKL). And, then running ex2.cpp .... to get error :<br>
<br>
Error 2 error: identifier "_intel_fast_memcpy" is undefined C:\cygwin\home\Hung\petsc-3.1-<br>
p7\include\petscsys.h 1775<br>
<br>
Please help me. Best regard Hung T. Nguyen<br>
<div><div></div><div class="h5"><br>
-----Original Message-----<br>
From: <a href="mailto:petsc-users-bounces@mcs.anl.gov">petsc-users-bounces@mcs.anl.gov</a> [mailto:<a href="mailto:petsc-users-bounces@mcs.anl.gov">petsc-users-bounces@mcs.anl.gov</a>] On Behalf Of Juha Jäykkä<br>
Sent: 21. februar 2011 13:10<br>
To: <a href="mailto:petsc-users@mcs.anl.gov">petsc-users@mcs.anl.gov</a><br>
Subject: Re: [petsc-users] KSPBuildSolution<br>
<br>
> > introduce new variables to reduce the problem to a first order equation.<br>
> > For example let g = f' and the new problem is F(f,g,g') = 0 with<br>
> > the additional equations g = f' now there are no second derivatives.<br>
> Let me see what happens if I do that...<br>
<br>
Ok, so this helps. Now I can get the solution to converge on a small lattice, of less than 20 points.<br>
<br>
Increasing the lattice gives divergent zig-zag "solutions". Now this is usual central differences behaviour: it decouples even lattice points from odd ones and now that I have both f and f' as unknowns, this decoupling is total. (It was not previously, since f'', computed from f, does not decouple.)<br>
<br>
Changing to simple forward differences does not help, but changing to three- point forward differences (=five-point stencil, but the backwards points are not used) fixes the problem and I now get convergence.<br>
<br>
That is, thanks for all the help. I can now return to my actual equation, which still does not converge with these tricks on any lattice larger than about 50 points. I suppose the problem here is similar and I just need to find a better discretisation.<br>
<br>
Cheers,<br>
Juha<br>
<br>
--<br>
-----------------------------------------------<br>
| Juha Jäykkä, <a href="mailto:juhaj@iki.fi">juhaj@iki.fi</a> |<br>
| <a href="http://www.maths.leeds.ac.uk/~juhaj" target="_blank">http://www.maths.leeds.ac.uk/~juhaj</a> |<br>
-----------------------------------------------<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <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>