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<p>Re:</p>
<p>Please, could you if possible, provide a basic example code. I do
not understand how to "go to the supercommunicator, incorporating
these two groups and use VecScatter"</p>
<p>Another question is: If I was to use "MPI calls", can I use Petsc
Vec as a buffer ? If so, which type should I indicate
(MPI_Datatype) in the let's say MPI_Isend method ?<br>
</p>
<p>Thanks<br>
</p>
<div class="moz-cite-prefix">On 16/02/2022 15:48, Matthew Knepley
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAMYG4G=neDrhnGhjW+Qc5D=W6wsbBZ__OwAgL=4sU7LT34mJaA@mail.gmail.com">
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<div dir="ltr">On Wed, Feb 16, 2022 at 9:47 AM Medane TCHAKOROM
<<a href="mailto:medane.tchakorom@univ-fcomte.fr"
moz-do-not-send="true" class="moz-txt-link-freetext">medane.tchakorom@univ-fcomte.fr</a>>
wrote:<br>
</div>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
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<p>Re:</p>
<p><br>
</p>
<p>It does not apply, because "<span
style="color:rgb(0,0,0);font-family:"Times New
Roman";font-size:medium;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">their
communicator must be on the same set of processes" .</span></p>
<p>In my case, I have two disjoint subcomm from
PETSC_COMM_WORD with same number of processes.<br>
</p>
<p>I want to send information (Petsc Vec) from one subcomm
to another subcomm.</p>
</div>
</blockquote>
<div>The way I do this is to go to the supercommunicator,
incorporating these two groups and use VecScatter.</div>
<div>The alternative is just to use custom MPI calls as you
say.</div>
<div><br>
</div>
<div> Thanks,</div>
<div><br>
</div>
<div> Matt <br>
</div>
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<div>
<p>Thanks<br>
</p>
<div>On 16/02/2022 15:43, Junchao Zhang wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">See Notes at <a
href="https://petsc.org/main/docs/manualpages/PetscSF/VecScatterCreate.html"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://petsc.org/main/docs/manualpages/PetscSF/VecScatterCreate.html</a>
<div><br>
</div>
<div>Does it apply to your case? </div>
<div><br clear="all">
<div>
<div dir="ltr">
<div dir="ltr">--Junchao Zhang</div>
</div>
</div>
<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, Feb 16, 2022
at 8:12 AM Medane TCHAKOROM <<a
href="mailto:medane.tchakorom@univ-fcomte.fr"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">medane.tchakorom@univ-fcomte.fr</a>>
wrote:<br>
</div>
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0px 0.8ex;border-left:1px solid
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<div>
<p>Re:</p>
<p>I forgot to mention that the nodes are in
differents communicators. Does VecScatter
functionnality still applies ?</p>
<p>Thanks.<br>
</p>
<div>On 16/02/2022 15:03, Matthew Knepley wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">On Wed, Feb 16, 2022 at 8:55 AM
Medane TCHAKOROM <<a
href="mailto:medane.tchakorom@univ-fcomte.fr"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">medane.tchakorom@univ-fcomte.fr</a>>
wrote:<br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">Hello,<br>
<br>
I want to pass a Petsc Vec from one node
to another one. Is there any <br>
Petsc method for doing this<br>
</blockquote>
<div><br>
</div>
<div>You likely want the VecScatter
functionality. There is a discussion of
this in the manual: <a
href="https://petsc.org/main/docs/manual/vec/?highlight=vecscatter#sec-unstruct"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://petsc.org/main/docs/manual/vec/?highlight=vecscatter#sec-unstruct</a></div>
<div><br>
</div>
<div> Thanks,</div>
<div><br>
</div>
<div> Matt</div>
<div> </div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex"> or
should I use MPI_Irecv and MPI_Isend for
non-blocking communication ?<br>
<br>
When using MPI_Isend, can i send a Petsc
Vec, or should I get the array <br>
from it, and then send it ?<br>
<br>
Thanks<br>
<br>
</blockquote>
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-- <br>
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<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>
<div><br>
</div>
<div><a
href="http://www.cse.buffalo.edu/~knepley/"
target="_blank"
moz-do-not-send="true">https://www.cse.buffalo.edu/~knepley/</a><br>
</div>
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-- <br>
<div dir="ltr" class="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<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>
<div><br>
</div>
<div><a href="http://www.cse.buffalo.edu/~knepley/"
target="_blank" moz-do-not-send="true">https://www.cse.buffalo.edu/~knepley/</a><br>
</div>
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