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Things may go south in your computation made on A. To rule it out, I would check A directly to see if the results are correct for multiple processes.
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<div class="">Btw, MatGetColumnVector is efficient only for dense matrices. Why do you need it for sparse matrices?</div>
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<div class="">Hong (Mr.)<br class="">
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<div class="">On Nov 9, 2020, at 8:44 AM, Antoine Côté <<a href="mailto:Antoine.Cote3@USherbrooke.ca" class="">Antoine.Cote3@USherbrooke.ca</a>> wrote:</div>
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Hi,</div>
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I would like to retrieve the values of a column in a sparse Mat created with DMCreateMatrix(). I currently use MatGetColumnVector() to store values in a Vec "A". A computation is later made on each value in <span style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt;" class="">"A",
and the results are stored in another Vec "B" (that was initialized at "0.0" using VecSet()).</span></div>
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Code works fine on a single process. When I try multiple processes, some values are ignored i.e. Vec "B" contains the right results for some positions, while others stay at "0.0". I suspect it is because MatGetColumnVector() is "Not Collective".</div>
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What would be the best workaround?</div>
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Thank you very much,</div>
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Antoine Côté</div>
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