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Guido Schimmels - Revision history
2024-03-28T21:17:32Z
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GerdIsenberg at 09:22, 3 November 2019
2019-11-03T09:22:36Z
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<td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 09:22, 3 November 2019</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>=Forum Posts=</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>=Forum Posts=</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=19790 Re: Hash Table Size Versus Performance] by [[Guido Schimmels]], [[CCC]], June 02, 1998 » [[Transposition Table]]</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=19790 Re: Hash Table Size Versus Performance] by [[Guido Schimmels]], [[CCC]], June 02, 1998 » [[Transposition Table]]</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=20057 Question to Bob: Crafty , Alpha and FindBit()] by [[Guido Schimmels]], [[CCC]], June 05, 1998 » [[Crafty]], [[BitScan]]</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=20057 Question to Bob: Crafty , Alpha and FindBit()] by [[Guido Schimmels]], [[CCC]], June 05, 1998 » [[Crafty<ins class="diffchange diffchange-inline">]], [[DEC Alpha</ins>]], [[BitScan]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=20868 Re: Zero-width Window Null Move Search] by [[Guido Schimmels]], [[CCC]], June 18, 1998 » [[Principal Variation Search]], [[NegaScout]]</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=20868 Re: Zero-width Window Null Move Search] by [[Guido Schimmels]], [[CCC]], June 18, 1998 » [[Principal Variation Search]], [[NegaScout]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=23672 Failing low at the root] by [[Guido Schimmels]], [[CCC]], August 03, 1998 » [[Root]]</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* [https://www.stmintz.com/ccc/index.php?id=23672 Failing low at the root] by [[Guido Schimmels]], [[CCC]], August 03, 1998 » [[Root]]</div></td></tr>
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GerdIsenberg
https://www.chessprogramming.org/index.php?title=Guido_Schimmels&diff=15366&oldid=prev
GerdIsenberg: Created page with "'''Home * People * Guido Schimmels''' '''Guido Schimmels''',<br/> a German software developer contributing to FSF GNU and simil..."
2019-11-03T09:19:24Z
<p>Created page with "'''<a href="/Main_Page" title="Main Page">Home</a> * <a href="/People" title="People">People</a> * Guido Schimmels''' '''Guido Schimmels''',<br/> a German software developer contributing to <a href="/Free_Software_Foundation" title="Free Software Foundation">FSF GNU</a> and simil..."</p>
<p><b>New page</b></p><div>'''[[Main Page|Home]] * [[People]] * Guido Schimmels'''<br />
<br />
'''Guido Schimmels''',<br/><br />
a German software developer contributing to [[Free Software Foundation|FSF GNU]] and similar projects, such as [https://en.wikipedia.org/wiki/GNU_TeXmacs GNU TeXmacs] <ref>[http://www.texmacs.org/tmweb/manual/webman-about.en.html About TeXmacs (FSF GNU project)]</ref>, and the [https://en.wikipedia.org/wiki/ROX_Desktop ROX Desktop] <ref>[http://rox.sourceforge.net/desktop/node/270.html Tango Theme | ROX Desktop]</ref>. <br />
He further is contributor of the [https://en.wikipedia.org/wiki/Ultimate%2B%2B Ultimate++] framework <ref>[http://www.ultimatepp.org/app$ide$About$en-us.html Copyright © 1999-2019 Ultimate++ team :: Ultimate++]</ref>. <br />
In the late 90s and early 2000s, Guido Schimmels was engaged in computer chess programming, and made a couple of posts in [[CCC]].<br />
<br />
=PVS vs. NegaScout=<br />
Guido Schimmels in a [[CCC]] post on the difference of [[Principal Variation Search|PVS]] vs. [[NegaScout]] <ref>[https://www.stmintz.com/ccc/index.php?id=20868 Re: Zero-width Window Null Move Search] by [[Guido Schimmels]], [[CCC]], June 18, 1998</ref>:<br />
The difference is how they handle re-searches: PVS passes alpha/beta while NegaScout passes the value returned by the null window search instead of alpha. But then you can get a fail-low on the research due to [[Search Instability|search anonomalies]]. If that happens NegaScout returns the value from the first search. That means you will have a crippled [[Principal Variation|PV]]. Then there is a refinement [[Alexander Reinefeld|Reinefeld]] suggests which is to ommit the re-search at the last two plies (depth > 1) - but that won't work in a real program because of [[Extensions|search extensions]]. NegaScout is slightly an [https://en.wikipedia.org/wiki/Ivory_Tower ivory tower] variant of PVS (IMHO). <br />
<br />
==PVS==<br />
<pre><br />
value = PVS(-(alpha+1),-alpha)<br />
if(value > alpha && value < beta) {<br />
value = PVS(-beta,-alpha);<br />
}<br />
</pre><br />
==NegaScout==<br />
<pre><br />
value = NegaScout(-(alpha+1),-alpha)<br />
if(value > alpha && value < beta && depth > 1) {<br />
value2 = NegaScout(-beta,-value)<br />
value = max(value,value2);<br />
}<br />
</pre><br />
<br />
=Forum Posts=<br />
* [https://www.stmintz.com/ccc/index.php?id=19790 Re: Hash Table Size Versus Performance] by [[Guido Schimmels]], [[CCC]], June 02, 1998 » [[Transposition Table]]<br />
* [https://www.stmintz.com/ccc/index.php?id=20057 Question to Bob: Crafty , Alpha and FindBit()] by [[Guido Schimmels]], [[CCC]], June 05, 1998 » [[Crafty]], [[BitScan]]<br />
* [https://www.stmintz.com/ccc/index.php?id=20868 Re: Zero-width Window Null Move Search] by [[Guido Schimmels]], [[CCC]], June 18, 1998 » [[Principal Variation Search]], [[NegaScout]]<br />
* [https://www.stmintz.com/ccc/index.php?id=23672 Failing low at the root] by [[Guido Schimmels]], [[CCC]], August 03, 1998 » [[Root]]<br />
* [https://www.stmintz.com/ccc/index.php?id=25012 Books that help for evaluation] by [[Guido Schimmels]], [[CCC]], August 18, 1998 » [[Evaluation]] <br />
* [https://groups.google.com/d/msg/alt.religion.kibology/vMQhc1hJc7Q/xpnuVGQYZa4J Re: Atheist IQ vs Theist IQ] by [[Guido Schimmels]], [https://groups.google.com/forum/?fromgroups=#!forum/alt.religion.kibology alt.religion.kibology], August 18, 1999<br />
* [https://www.stmintz.com/ccc/index.php?id=230559 Re: GCC 3.1 fastest compiler at K7 !!] by [[Guido Schimmels]], [[CCC]], May 20, 2002<br />
<br />
=References= <br />
<references /><br />
'''[[People|Up one level]]'''<br />
[[Category:Programmer|Schimmels]]</div>
GerdIsenberg