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<p>Hi Guillaume</p>
<p><br>
</p>
<p>>My question: Is there a way to take advantage of the fact
that I have 32 cores on my computer with QGIS to make this
calculation? I don't understand why it is so slow.</p>
<p><br>
</p>
<p>Yes, there is. Compile the code from the
'processing_multithreaded_vector' branch in my repo
(<a class="moz-txt-link-freetext" href="https://github.com/mhugent/QGIS/tree/processing_multithreaded_vector">https://github.com/mhugent/QGIS/tree/processing_multithreaded_vector</a>).
It calculates the difference operation on multiple cores (see also
<a class="moz-txt-link-freetext" href="https://github.com/qgis/QGIS/pull/33365">https://github.com/qgis/QGIS/pull/33365</a>).</p>
<p><br>
</p>
<p>Regards,</p>
<p>Marco<br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">Am 22.10.20 um 03:05 schrieb guillaume
martel:<br>
</div>
<blockquote type="cite"
cite="mid:QB1PR01MB27226855C087076A9A1F3DEFE81D0@QB1PR01MB2722.CANPRD01.PROD.OUTLOOK.COM">
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Hi,</div>
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<br>
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I don't know if I'm writing at the wrong place... </div>
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<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
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I have 2 shapefiles and I want to do a "difference operation" (<a
href="https://docs.qgis.org/3.10/en/docs/user_manual/processing_algs/qgis/vectoroverlay.html"
id="LPlnk774000" moz-do-not-send="true">https://docs.qgis.org/3.10/en/docs/user_manual/processing_algs/qgis/vectoroverlay.html</a>).</div>
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<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
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My issue is as follow: Even though I have a powerful computer,
after 5 days the calculation is only at 5%. </div>
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<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
My question: Is there a way to take advantage of the fact that I
have 32 cores on my computer with QGIS to make this calculation?
I don't understand why it is so slow.</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
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Thank you for your help.</div>
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<br>
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
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Guillaume</div>
<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
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<pre class="moz-signature" cols="72">--
Dr. Marco Hugentobler
Sourcepole - Linux & Open Source Solutions
Weberstrasse 5, CH-8004 Zürich, Switzerland
<a class="moz-txt-link-abbreviated" href="mailto:marco.hugentobler@sourcepole.ch">marco.hugentobler@sourcepole.ch</a> <a class="moz-txt-link-freetext" href="http://www.sourcepole.ch">http://www.sourcepole.ch</a></pre>
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