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<div class="moz-cite-prefix">On 07/15/2013 08:54 PM, Matthew Knepley
wrote:<br>
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<p dir="ltr"><br>
On Jul 15, 2013 1:51 PM, "Umut Tabak" <<a
moz-do-not-send="true" href="mailto:u.tabak@tudelft.nl">u.tabak@tudelft.nl</a>>
wrote:<br>
><br>
> Hi list,<br>
><br>
> I was wondering the reason why classical gram schmidt is
used in the orthogonalizations in the gmres implementation as
default? As far as I remember, this was unstable numerically.</p>
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Hi Matt,<br>
<br>
Excuse my naive question but mathematically they are equivalent so
what is the source of speed boost? And can you please direct me to
one or two of these references?<br>
<br>
Best,<br>
Umut
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<p dir="ltr">Its much faster. Try the modified option and compare.
There are many papers claiming that classical+selective
reorthogonalization is just as stable.</p>
<p dir="ltr"> Matt<br>
><br>
> Best,<br>
> Umut<br>
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