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<div class="moz-cite-prefix">On 10/11/2015 8:47 PM, Matthew Knepley
wrote:<br>
</div>
<blockquote
cite="mid:CAMYG4GkYndTXrY22=3Jq=HYjoLid3Z+_E_cGRmMoQT7fShdACA@mail.gmail.com"
type="cite">
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<div class="gmail_extra">
<div class="gmail_quote">On Tue, Nov 10, 2015 at 6:30 AM, TAY
wee-beng <span dir="ltr"><<a moz-do-not-send="true"
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 bgcolor="#FFFFFF" text="#000000"> <br>
<div>On 10/11/2015 8:27 PM, Matthew Knepley wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Tue, Nov 10, 2015 at
3:27 AM, TAY wee-beng <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:zonexo@gmail.com"
target="_blank"><a class="moz-txt-link-abbreviated" href="mailto:zonexo@gmail.com">zonexo@gmail.com</a></a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">Hi,<br>
<br>
Inside my subroutine, I need to access the DA
variable cu_types_array frequently.<br>
<br>
So I need to call DMDAVecGetArrayF90 and
DMDAVecRestoreArrayF90 before and after
frequently.<br>
<br>
Is this necessary? Can I call
DMDAVecGetArrayF90 at the start and only call
DMDAVecRestoreArrayF90 towards the end, where
I don't need to modify the values of
cu_types_array anymore?<br>
<br>
Will this cause memory corruption?<br>
</blockquote>
<div><br>
</div>
<div>You cannot use any other vector operations
before you have called Restore.</div>
</div>
</div>
</div>
</blockquote>
<br>
Hi,<br>
<br>
What do you mean by vector operations? I will just be
doing some maths operation to change the values in
cu_types_array. Is that fine?</div>
</blockquote>
<div><br>
</div>
<div>While you have the array, no other operation can change
the values.</div>
</div>
</div>
</div>
</blockquote>
Hi,<br>
<br>
Let me clarify this. I declare in this way:<br>
<br>
DM da_cu_types<br>
<br>
Vec cu_types_local,cu_types_global<br>
<br>
PetscScalar,pointer :: cu_types_array(:,:,:)<br>
<br>
call
DMDACreate3d(MPI_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,(end_ijk_uniform(1)
- sta_ijk_uniform(1) + 1),(end_ijk_uniform(2) - sta_ijk_uniform(2) +
1),&<br>
<br>
(end_ijk_uniform(3) - sta_ijk_uniform(3) +
1),PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,stencil_width_IIB,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,da_cu_types,ierr)<br>
<br>
call DMCreateGlobalVector(da_cu_types,cu_types_global,ierr)<br>
<br>
call DMCreateLocalVector(da_cu_types,cu_types_local,ierr)<br>
<br>
So when I need to change the values in DA variable cu_types, I call:<br>
<br>
call
DMDAVecGetArrayF90(da_cu_types,cu_types_local,cu_types_array,ierr)<br>
<br>
.... math operations, changing the values of cu_types_array, such
as:<br>
<br>
cu_types_array = 0.d0<br>
<br>
call
DMDAVecRestoreArrayF90(da_cu_types,cu_types_local,cu_types_array,ierr)<br>
<br>
1st of all, does these DMDAVecGetArrayF90 and DMDAVecRestoreArrayF90
take a lot of time, especially if I call them many times.<br>
<br>
Next qn is whether if I can call DMDAVecGetArrayF90 at the start,
and DMDAVecRestoreArrayF90 after operations similar to the one above
is finished.<br>
<br>
Thanks.<br>
<blockquote
cite="mid:CAMYG4GkYndTXrY22=3Jq=HYjoLid3Z+_E_cGRmMoQT7fShdACA@mail.gmail.com"
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 bgcolor="#FFFFFF" text="#000000">
<blockquote type="cite">
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<div class="gmail_extra">
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex"> Also, must the array
be restored using DMDAVecRestoreArrayF90
before calling
DMLocalToLocalBegin,DMLocalToLocalEnd?</blockquote>
<div><br>
</div>
<div>Yes.</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"><span><font
color="#888888"><br>
<span class="HOEnZb"><font color="#888888">
-- <br>
Thank you.<br>
<br>
Yours sincerely,<br>
<br>
TAY wee-beng<br>
<br>
</font></span></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>
<div>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>
</font></span></div>
</div>
</blockquote>
<br>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div class="gmail_signature">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>
</div>
</blockquote>
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