<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Sat, Apr 19, 2014 at 10:16 AM, TAY wee-beng <span dir="ltr"><<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>On 19/4/2014 10:55 PM, Matthew Knepley
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Sat, Apr 19, 2014 at 9:14 AM, TAY
wee-beng <span dir="ltr"><<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div>On 19/4/2014 6:48 PM, Matthew Knepley wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Sat, Apr 19, 2014 at
4:59 AM, TAY wee-beng <span dir="ltr"><<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div>On 19/4/2014 1:17 PM, Barry Smith
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On Apr 19,
2014, at 12:11 AM, TAY wee-beng <<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>>
wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On 19/4/2014
12:10 PM, Barry Smith wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On Apr 18,
2014, at 9:57 PM, TAY wee-beng <<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>>
wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> On
19/4/2014 3:53 AM, Barry Smith
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Hmm,<br>
<br>
Interface
DMDAVecGetArrayF90<br>
Subroutine
DMDAVecGetArrayF903(da1,
v,d1,ierr)<br>
USE_DM_HIDE<br>
DM_HIDE da1<br>
VEC_HIDE v<br>
PetscScalar,pointer
:: d1(:,:,:)<br>
PetscErrorCode ierr<br>
End Subroutine<br>
<br>
So the d1 is a F90 POINTER.
But your subroutine seems to be
treating it as a “plain old
Fortran array”?<br>
real(8), intent(inout) ::
u(:,:,:),v(:,:,:),w(:,:,:)<br>
</blockquote>
</blockquote>
</blockquote>
Hi,<br>
<br>
So d1 is a pointer, and it's different
if I declare it as "plain old Fortran
array"? Because I declare it as a
Fortran array and it works w/o any
problem if I only call
DMDAVecGetArrayF90 and
DMDAVecRestoreArrayF90 with "u".<br>
<br>
But if I call DMDAVecGetArrayF90 and
DMDAVecRestoreArrayF90 with "u", "v"
and "w", error starts to happen. I
wonder why...<br>
<br>
Also, supposed I call:<br>
<br>
call
DMDAVecGetArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
u_array ....<br>
<br>
v_array .... etc<br>
<br>
Now to restore the array, does it
matter the sequence they are restored?<br>
</blockquote>
No it should not matter. If it
matters that is a sign that memory has
been written to incorrectly earlier in
the code.<br>
<br>
</blockquote>
</div>
</div>
Hi,<br>
<br>
Hmm, I have been getting different results on
different intel compilers. I'm not sure if MPI
played a part but I'm only using a single
processor. In the debug mode, things run
without problem. In optimized mode, in some
cases, the code aborts even doing simple
initialization:
<div> <br>
<br>
call
DMDAVecGetArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
</div>
call
DMDAVecGetArrayF90(da_p,p_local,p_array,ierr)<br>
<br>
u_array = 0.d0<br>
<br>
v_array = 0.d0<br>
<br>
w_array = 0.d0<br>
<br>
p_array = 0.d0<br>
<br>
<br>
call
DMDAVecRestoreArrayF90(da_p,p_local,p_array,ierr)
<div><br>
<br>
call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
</div>
The code aborts at call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr),
giving segmentation error. But other version
of intel compiler passes thru this part w/o
error. Since the response is different among
different compilers, is this PETSc or intel 's
bug? Or mvapich or openmpi?</blockquote>
<div><br>
</div>
<div>We do this is a bunch of examples. Can you
reproduce this different behavior in
src/dm/examples/tutorials/ex11f90.F?</div>
</div>
</div>
</div>
</blockquote>
<br>
Hi Matt,<br>
<br>
Do you mean putting the above lines into ex11f90.F and
test?<br>
</div>
</blockquote>
<div><br>
</div>
<div>It already has DMDAVecGetArray(). Just run it.</div>
</div>
</div>
</div>
</blockquote>
<br>
Hi,<br>
<br>
It worked. The differences between mine and the code is the way the
fortran modules are defined, and the ex11f90 only uses global
vectors. Does it make a difference whether global or local vectors
are used? Because the way it accesses x1 only touches the local
region.<br></div></blockquote><div><br></div><div>No the global/local difference should not matter.</div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Also, before using DMDAVecGetArrayF90, DMGetGlobalVector must be
used 1st, is that so? I can't find the equivalent for local vector
though.<br></div></blockquote><div><br></div><div>DMGetLocalVector()</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 text="#000000" bgcolor="#FFFFFF">
Thanks.<br>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<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 text="#000000" bgcolor="#FFFFFF"> Thanks<br>
<br>
Regards.<br>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<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>
<div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> As in w, then
v and u?<br>
<br>
call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr)<br>
call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
thanks<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Note also that the beginning and
end indices of the u,v,w, are
different for each process see
for example <a href="http://www.mcs.anl.gov/petsc/petsc-3.4/src/dm/examples/tutorials/ex11f90.F" target="_blank">http://www.mcs.anl.gov/petsc/petsc-3.4/src/dm/examples/tutorials/ex11f90.F</a>
(and they do not start at 1).
This is how to get the loop
bounds.<br>
</blockquote>
Hi,<br>
<br>
In my case, I fixed the u,v,w such
that their indices are the same. I
also checked using DMDAGetCorners
and DMDAGetGhostCorners. Now the
problem lies in my subroutine
treating it as a “plain old
Fortran array”.<br>
<br>
If I declare them as pointers,
their indices follow the C 0 start
convention, is that so?<br>
</blockquote>
Not really. It is that in each
process you need to access them from
the indices indicated by
DMDAGetCorners() for global vectors
and DMDAGetGhostCorners() for local
vectors. So really C or Fortran
doesn’t make any difference.<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> So my
problem now is that in my old MPI
code, the u(i,j,k) follow the
Fortran 1 start convention. Is
there some way to manipulate such
that I do not have to change my
u(i,j,k) to u(i-1,j-1,k-1)?<br>
</blockquote>
If you code wishes to access them
with indices plus one from the
values returned by DMDAGetCorners()
for global vectors and
DMDAGetGhostCorners() for local
vectors then you need to manually
subtract off the 1.<br>
<br>
Barry<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Thanks.<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Barry<br>
<br>
On Apr 18, 2014, at 10:58 AM,
TAY wee-beng <<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>>
wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Hi,<br>
<br>
I tried to pinpoint the
problem. I reduced my job size
and hence I can run on 1
processor. Tried using
valgrind but perhaps I'm using
the optimized version, it
didn't catch the error,
besides saying "Segmentation
fault (core dumped)"<br>
<br>
However, by re-writing my
code, I found out a few
things:<br>
<br>
1. if I write my code this
way:<br>
<br>
call
DMDAVecGetArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
u_array = ....<br>
<br>
v_array = ....<br>
<br>
w_array = ....<br>
<br>
call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
The code runs fine.<br>
<br>
2. if I write my code this
way:<br>
<br>
call
DMDAVecGetArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecGetArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
call
uvw_array_change(u_array,v_array,w_array)
-> this subroutine does the
same modification as the
above.<br>
<br>
call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)
-> error<br>
<br>
where the subroutine is:<br>
<br>
subroutine
uvw_array_change(u,v,w)<br>
<br>
real(8), intent(inout) ::
u(:,:,:),v(:,:,:),w(:,:,:)<br>
<br>
u ...<br>
v...<br>
w ...<br>
<br>
end subroutine
uvw_array_change.<br>
<br>
The above will give an error
at :<br>
<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
3. Same as above, except I
change the order of the last 3
lines to:<br>
<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)<br>
<br>
call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr)<br>
<br>
So they are now in reversed
order. Now it works.<br>
<br>
4. Same as 2 or 3, except the
subroutine is changed to :<br>
<br>
subroutine
uvw_array_change(u,v,w)<br>
<br>
real(8), intent(inout) ::
u(start_indices(1):end_indices(1),start_indices(2):end_indices(2),start_indices(3):end_indices(3))<br>
<br>
real(8), intent(inout) ::
v(start_indices(1):end_indices(1),start_indices(2):end_indices(2),start_indices(3):end_indices(3))<br>
<br>
real(8), intent(inout) ::
w(start_indices(1):end_indices(1),start_indices(2):end_indices(2),start_indices(3):end_indices(3))<br>
<br>
u ...<br>
v...<br>
w ...<br>
<br>
end subroutine
uvw_array_change.<br>
<br>
The start_indices and
end_indices are simply to
shift the 0 indices of C
convention to that of the 1
indices of the Fortran
convention. This is necessary
in my case because most of my
codes start array counting at
1, hence the "trick".<br>
<br>
However, now no matter which
order of the
DMDAVecRestoreArrayF90 (as in
2 or 3), error will occur at
"call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)
"<br>
<br>
So did I violate and cause
memory corruption due to the
trick above? But I can't think
of any way other than the
"trick" to continue using the
1 indices convention.<br>
<br>
Thank you.<br>
<br>
Yours sincerely,<br>
<br>
TAY wee-beng<br>
<br>
On 15/4/2014 8:00 PM, Barry
Smith wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Try running under valgrind
<a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind" target="_blank">http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind</a><br>
<br>
<br>
On Apr 14, 2014, at 9:47 PM,
TAY wee-beng <<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>>
wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Barry,<br>
<br>
As I mentioned earlier,
the code works fine in
PETSc debug mode but fails
in non-debug mode.<br>
<br>
I have attached my code.<br>
<br>
Thank you<br>
<br>
Yours sincerely,<br>
<br>
TAY wee-beng<br>
<br>
On 15/4/2014 2:26 AM,
Barry Smith wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Please send the code
that creates da_w and
the declarations of
w_array<br>
<br>
Barry<br>
<br>
On Apr 14, 2014, at 9:40
AM, TAY wee-beng<br>
<<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>><br>
wrote:<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi Barry,<br>
<br>
I'm not too sure how
to do it. I'm running
mpi. So I run:<br>
<br>
mpirun -n 4 ./a.out
-start_in_debugger<br>
<br>
I got the msg below.
Before the gdb windows
appear (thru x11), the
program aborts.<br>
<br>
Also I tried running
in another cluster and
it worked. Also tried
in the current cluster
in debug mode and it
worked too.<br>
<br>
mpirun -n 4 ./a.out
-start_in_debugger<br>
--------------------------------------------------------------------------<br>
An MPI process has
executed an operation
involving a call to
the<br>
"fork()" system call
to create a child
process. Open MPI is
currently<br>
operating in a
condition that could
result in memory
corruption or<br>
other system errors;
your MPI job may hang,
crash, or produce
silent<br>
data corruption. The
use of fork() (or
system() or other
calls that<br>
create child
processes) is strongly
discouraged.<br>
<br>
The process that
invoked fork was:<br>
<br>
Local host:
n12-76 (PID 20235)<br>
MPI_COMM_WORLD
rank: 2<br>
<br>
If you are *absolutely
sure* that your
application will
successfully<br>
and correctly survive
a call to fork(), you
may disable this
warning<br>
by setting the
mpi_warn_on_fork MCA
parameter to 0.<br>
--------------------------------------------------------------------------<br>
[2]PETSC ERROR: PETSC:
Attaching gdb to
./a.out of pid 20235
on display
localhost:50.0 on
machine n12-76<br>
[0]PETSC ERROR: PETSC:
Attaching gdb to
./a.out of pid 20233
on display
localhost:50.0 on
machine n12-76<br>
[1]PETSC ERROR: PETSC:
Attaching gdb to
./a.out of pid 20234
on display
localhost:50.0 on
machine n12-76<br>
[3]PETSC ERROR: PETSC:
Attaching gdb to
./a.out of pid 20236
on display
localhost:50.0 on
machine n12-76<br>
[n12-76:20232] 3 more
processes have sent
help message
help-mpi-runtime.txt /
mpi_init:warn-fork<br>
[n12-76:20232] Set MCA
parameter
"orte_base_help_aggregate"
to 0 to see all help /
error messages<br>
<br>
....<br>
<br>
1<br>
[1]PETSC ERROR:
------------------------------------------------------------------------<br>
[1]PETSC ERROR: Caught
signal number 11 SEGV:
Segmentation
Violation, probably
memory access out of
range<br>
[1]PETSC ERROR: Try
option
-start_in_debugger or
-on_error_attach_debugger<br>
[1]PETSC ERROR: or see<br>
<a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[1]PETSC" target="_blank">http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[1]PETSC</a>
ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a><br>
on GNU/linux and
Apple Mac OS X to find
memory corruption
errors<br>
[1]PETSC ERROR:
configure using
--with-debugging=yes,
recompile, link, and
run<br>
[1]PETSC ERROR: to get
more information on
the crash.<br>
[1]PETSC ERROR: User
provided function()
line 0 in unknown
directory unknown file
(null)<br>
[3]PETSC ERROR:
------------------------------------------------------------------------<br>
[3]PETSC ERROR: Caught
signal number 11 SEGV:
Segmentation
Violation, probably
memory access out of
range<br>
[3]PETSC ERROR: Try
option
-start_in_debugger or
-on_error_attach_debugger<br>
[3]PETSC ERROR: or see<br>
<a href="http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[3]PETSC" target="_blank">http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[3]PETSC</a>
ERROR: or try <a href="http://valgrind.org" target="_blank">http://valgrind.org</a><br>
on GNU/linux and
Apple Mac OS X to find
memory corruption
errors<br>
[3]PETSC ERROR:
configure using
--with-debugging=yes,
recompile, link, and
run<br>
[3]PETSC ERROR: to get
more information on
the crash.<br>
[3]PETSC ERROR: User
provided function()
line 0 in unknown
directory unknown file
(null)<br>
<br>
...<br>
Thank you.<br>
<br>
Yours sincerely,<br>
<br>
TAY wee-beng<br>
<br>
On 14/4/2014 9:05 PM,
Barry Smith wrote:<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Because IO
doesn’t always get
flushed immediately
it may not be
hanging at this
point. It is better
to use the option
-start_in_debugger
then type cont in
each debugger window
and then when you
think it is
“hanging” do a
control C in each
debugger window and
type where to see
where each process
is you can also look
around in the
debugger at
variables to see why
it is “hanging” at
that point.<br>
<br>
Barry<br>
<br>
This routines
don’t have any
parallel
communication in
them so are unlikely
to hang.<br>
<br>
On Apr 14, 2014, at
6:52 AM, TAY
wee-beng<br>
<br>
<<a href="mailto:zonexo@gmail.com" target="_blank">zonexo@gmail.com</a>><br>
<br>
wrote:<br>
<br>
<br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
My code hangs and
I added in
mpi_barrier and
print to catch the
bug. I found that
it hangs after
printing "7". Is
it because I'm
doing something
wrong? I need to
access the u,v,w
array so I use
DMDAVecGetArrayF90.
After access, I
use
DMDAVecRestoreArrayF90.<br>
<br>
call
DMDAVecGetArrayF90(da_u,u_local,u_array,ierr)<br>
call
MPI_Barrier(MPI_COMM_WORLD,ierr);
if (myid==0)
print *,"3"<br>
call
DMDAVecGetArrayF90(da_v,v_local,v_array,ierr)<br>
call
MPI_Barrier(MPI_COMM_WORLD,ierr);
if (myid==0)
print *,"4"<br>
call
DMDAVecGetArrayF90(da_w,w_local,w_array,ierr)<br>
call
MPI_Barrier(MPI_COMM_WORLD,ierr);
if (myid==0)
print *,"5"<br>
call
I_IIB_uv_initial_1st_dm(I_cell_no_u1,I_cell_no_v1,I_cell_no_w1,I_cell_u1,I_cell_v1,I_cell_w1,u_array,v_array,w_array)<br>
call
MPI_Barrier(MPI_COMM_WORLD,ierr);
if (myid==0)
print *,"6"<br>
call
DMDAVecRestoreArrayF90(da_w,w_local,w_array,ierr)
!must be in
reverse order<br>
call
MPI_Barrier(MPI_COMM_WORLD,ierr);
if (myid==0)
print *,"7"<br>
call
DMDAVecRestoreArrayF90(da_v,v_local,v_array,ierr)<br>
call
MPI_Barrier(MPI_COMM_WORLD,ierr);
if (myid==0)
print *,"8"<br>
call
DMDAVecRestoreArrayF90(da_u,u_local,u_array,ierr)<br>
-- <br>
Thank you.<br>
<br>
Yours sincerely,<br>
<br>
TAY wee-beng<br>
<br>
<br>
<br>
</blockquote>
</blockquote>
</blockquote>
</blockquote>
<code.txt><br>
</blockquote>
</blockquote>
</blockquote>
</blockquote>
</blockquote>
</blockquote>
</blockquote>
</blockquote>
<br>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all"><span class="HOEnZb"><font color="#888888">
<span><font color="#888888">
<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 </font></span></font></span></div><span class="HOEnZb"><font color="#888888">
</font></span></div><span class="HOEnZb"><font color="#888888">
</font></span></blockquote><span class="HOEnZb"><font color="#888888">
<br>
</font></span></div><span class="HOEnZb"><font color="#888888">
</font></span></blockquote><span class="HOEnZb"><font color="#888888">
</font></span></div><span class="HOEnZb"><font color="#888888">
<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
</font></span></div>
</div>
</blockquote>
<br>
</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
</div></div>