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	<title>4Geeks.de &#187; Uni</title>
	<atom:link href="http://www.4geeks.de/blog/archives/category/uni/feed/" rel="self" type="application/rss+xml" />
	<link>http://www.4geeks.de/blog</link>
	<description>-.-</description>
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		<title>Molecular Dynamics</title>
		<link>http://www.4geeks.de/blog/archives/2009/02/molecular-dynamics/</link>
		<comments>http://www.4geeks.de/blog/archives/2009/02/molecular-dynamics/#comments</comments>
		<pubDate>Sat, 14 Feb 2009 21:22:27 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[Uni]]></category>
		<category><![CDATA[c++]]></category>
		<category><![CDATA[molecular dynamics]]></category>
		<category><![CDATA[numeric]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/?p=184</guid>
		<description><![CDATA[I created a little video with the md simulation, I&#8217;m working on for my diploma thesis. It simulates condensing Argon atoms using 8 cpus and around 130 cpu hours. Parallelization was done with Space-Filling curves. I used around 500 thousand particles &#8230; try that with your standard O(n2) algorithms. Condensing Argon Of course I used [...]]]></description>
			<content:encoded><![CDATA[<p>I created a little video with the md simulation, I&#8217;m working on for my diploma thesis. It simulates condensing Argon atoms using 8 cpus and around 130 cpu hours. Parallelization was done with <a href="http://en.wikipedia.org/wiki/Space_filling_curve">Space-Filling curves</a>. I used around 500 thousand particles &#8230; try that with your standard O(n<sup>2</sup>) algorithms.</p>
<p><a href="http://www.youtube.com/watch?v=J43ERHsH8Do">Condensing Argon</a></p>
<p>Of course I used some fanciful coloring.</p>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Mathematik</title>
		<link>http://www.4geeks.de/blog/archives/2008/12/mathematik/</link>
		<comments>http://www.4geeks.de/blog/archives/2008/12/mathematik/#comments</comments>
		<pubDate>Tue, 16 Dec 2008 23:56:43 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[Uni]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/?p=165</guid>
		<description><![CDATA[Erster Hauptsatz über die praktische Bedeutung von Schul-/Universitäts-Mathematik: Wenn man eine kubische Gleichung lösen soll, ist eine der Nullstellen immer -1, 0 oder 1.]]></description>
			<content:encoded><![CDATA[<p>Erster Hauptsatz über die praktische Bedeutung von Schul-/Universitäts-Mathematik:</p>
<blockquote><p>Wenn man eine kubische Gleichung lösen soll, ist eine der Nullstellen immer -1, 0 oder 1.</p></blockquote>
]]></content:encoded>
			<wfw:commentRss>http://www.4geeks.de/blog/archives/2008/12/mathematik/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Learning Clock</title>
		<link>http://www.4geeks.de/blog/archives/2008/07/learning-clock/</link>
		<comments>http://www.4geeks.de/blog/archives/2008/07/learning-clock/#comments</comments>
		<pubDate>Mon, 21 Jul 2008 20:35:32 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[English]]></category>
		<category><![CDATA[Uni]]></category>
		<category><![CDATA[web 2.0]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/?p=139</guid>
		<description><![CDATA[Check out the Learning Clock. It&#8217;s nearly too stupid to be true but still a fellow student created it. Don&#8217;t press the wrong buttons!]]></description>
			<content:encoded><![CDATA[<p>Check out the <a href="http://home.in.tum.de/~boehnel/clock/">Learning Clock</a>.</p>
<p>It&#8217;s nearly too stupid to be true but still a fellow student created it. Don&#8217;t press the wrong buttons!</p>
]]></content:encoded>
			<wfw:commentRss>http://www.4geeks.de/blog/archives/2008/07/learning-clock/feed/</wfw:commentRss>
		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Tschüss Semesterticket&#8230;</title>
		<link>http://www.4geeks.de/blog/archives/2008/07/tschuss-semesterticket/</link>
		<comments>http://www.4geeks.de/blog/archives/2008/07/tschuss-semesterticket/#comments</comments>
		<pubDate>Mon, 14 Jul 2008 21:39:29 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[Uni]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/?p=138</guid>
		<description><![CDATA[Der MVV hat ohne ein Angebot abzugeben oder sich mit den beteiligten Parteien zu beraten die Pläne für ein Semesterticket begraben. Meine Meinung: Es geht wie üblich um Geld und um Macht. Also nur um Geld. Irgendwie schade, allerdings ist meine Zeit als Student sowieso bald zu Ende. Zu meinen Lebzeiten hätte es das Ding [...]]]></description>
			<content:encoded><![CDATA[<p>Der MVV hat ohne ein Angebot abzugeben oder sich mit den beteiligten Parteien zu beraten die Pläne für ein Semesterticket <a href="http://asta.fs.tum.de/news-1/mvg-und-s-bahn-ziehen-beim-semesterticket-die-notbremse/">begraben</a>.</p>
<p>Meine Meinung:</p>
<p>Es geht wie üblich um Geld und um Macht. Also nur um Geld. Irgendwie schade, allerdings ist meine Zeit als Student sowieso bald zu Ende. Zu meinen Lebzeiten hätte es das Ding sowieso nicht mehr gegeben, aber um die nachfolgenden Generationen tut es mir schon leid. Und eine Schande ist es auch &#8230; Deutschlands beste Universitäten, aber kein  Semesterticket.</p>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Klausur</title>
		<link>http://www.4geeks.de/blog/archives/2008/06/klausur/</link>
		<comments>http://www.4geeks.de/blog/archives/2008/06/klausur/#comments</comments>
		<pubDate>Thu, 05 Jun 2008 20:05:32 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[Uni]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/?p=133</guid>
		<description><![CDATA[Die Korrektur der Midterm ist abgeschlossen. Alle Punkte sind verteilt, es sind keine mehr übrig Klausur korrigieren ist echt anstrengend &#8230; Am Anfang ist es noch ganz lustig, aber irgendwann beißt man nur noch in die Tischplatte wegen der immer gleichen unnötigen Fehler.]]></description>
			<content:encoded><![CDATA[<blockquote><p>Die Korrektur der Midterm ist abgeschlossen. Alle Punkte sind verteilt,  es sind keine mehr übrig</p></blockquote>
<p>Klausur korrigieren ist echt anstrengend &#8230; Am Anfang ist es noch ganz lustig, aber irgendwann beißt man nur noch in die Tischplatte wegen der immer gleichen unnötigen Fehler.</p>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Vortex</title>
		<link>http://www.4geeks.de/blog/archives/2008/02/vortex/</link>
		<comments>http://www.4geeks.de/blog/archives/2008/02/vortex/#comments</comments>
		<pubDate>Sat, 09 Feb 2008 15:19:26 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[English]]></category>
		<category><![CDATA[Uni]]></category>
		<category><![CDATA[Use The Source]]></category>
		<category><![CDATA[cfd]]></category>
		<category><![CDATA[flow]]></category>
		<category><![CDATA[fluid]]></category>
		<category><![CDATA[vortex]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/archives/2008/02/vortex/</guid>
		<description><![CDATA[I updated my code to support arbitrary geometries and fixed some more bug and was finally able to get some stable results for another nice problem: The Von Kármán vortex street Instead of a cylinder, I used a tilted plat, but it works nevertheless and is, imho, more interesting, because its no longer symmetric.]]></description>
			<content:encoded><![CDATA[<p>I updated my code to support arbitrary geometries and fixed some more bug and was finally able to get some <a href="http://www.youtube.com/watch?v=zasZF-h6Jrg">stable results</a> for another nice problem:</p>
<p>The <a href="http://en.wikipedia.org/wiki/Von_K%C3%A1rm%C3%A1n_vortex_street">Von Kármán vortex street</a></p>
<p>Instead of a cylinder, I used a tilted plat, but it works nevertheless and is, imho, more interesting, because its no longer symmetric.</p>
]]></content:encoded>
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		</item>
		<item>
		<title>Lid-driven cavity</title>
		<link>http://www.4geeks.de/blog/archives/2008/02/lid-driven-cavity/</link>
		<comments>http://www.4geeks.de/blog/archives/2008/02/lid-driven-cavity/#comments</comments>
		<pubDate>Wed, 06 Feb 2008 16:23:38 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[English]]></category>
		<category><![CDATA[Uni]]></category>
		<category><![CDATA[Use The Source]]></category>
		<category><![CDATA[cavity]]></category>
		<category><![CDATA[cfd]]></category>
		<category><![CDATA[flow]]></category>
		<category><![CDATA[fluid]]></category>
		<category><![CDATA[numeric]]></category>
		<category><![CDATA[simulation]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/archives/2008/02/lid-driven-cavity/</guid>
		<description><![CDATA[A small video showing my self-programmed cfd code simulating a lid-driven cavity flow. I used a 200&#215;200 grid to simulate a fluid with Reynolds number of 500. The whole simulation took about 15 minutes to run on a P4. The visualization was done with Paraview, which produced the streamlines from the velocity field. I try [...]]]></description>
			<content:encoded><![CDATA[<p>A small <a href="http://www.youtube.com/watch?v=chM2YU3OnKI">video</a> showing my self-programmed <a href="http://en.wikipedia.org/wiki/Computational_fluid_dynamics">cfd</a> code simulating a lid-driven cavity flow. I used a 200&#215;200 grid to simulate a fluid with <a href="http://en.wikipedia.org/wiki/Reynolds_number">Reynolds number</a> of 500. The whole simulation took about 15 minutes to run on a P4. The visualization was done with <a href="http://www.paraview.org/">Paraview</a>, which produced the streamlines from the velocity field.</p>
<p>I try to implement some more boundary conditions soon, so i can produce some more interesting examples.</p>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Bahnstreik</title>
		<link>http://www.4geeks.de/blog/archives/2007/11/bahnstreik/</link>
		<comments>http://www.4geeks.de/blog/archives/2007/11/bahnstreik/#comments</comments>
		<pubDate>Sat, 17 Nov 2007 20:47:16 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[Uni]]></category>
		<category><![CDATA[Bahn]]></category>
		<category><![CDATA[Kaffee]]></category>
		<category><![CDATA[Streik]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/archives/2007/11/bahnstreik/</guid>
		<description><![CDATA[Mit einem Gerücht muss ich auf jeden Fall aufräumen: In den Medien wurde wiederholt behauptet die Bahn würde an großen Bahnhöfen umsonst Kaffee an wartende Fahrgäste verteilen. Das ist so nicht ganz richtig: Die verteilen nur gefärbtes, heißes Wasser &#8230; mit Kaffee hat das nichts zu tun.]]></description>
			<content:encoded><![CDATA[<p>Mit einem Gerücht muss ich auf jeden Fall aufräumen:</p>
<p>In den Medien wurde wiederholt behauptet die Bahn würde an großen Bahnhöfen umsonst Kaffee an wartende Fahrgäste verteilen.</p>
<p>Das ist so nicht ganz richtig:</p>
<p>Die verteilen nur gefärbtes, heißes Wasser &#8230; mit Kaffee hat das nichts zu tun.</p>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Calling Python functions from SWIG/C++</title>
		<link>http://www.4geeks.de/blog/archives/2007/10/calling-python-functions-from-swigc/</link>
		<comments>http://www.4geeks.de/blog/archives/2007/10/calling-python-functions-from-swigc/#comments</comments>
		<pubDate>Fri, 05 Oct 2007 19:39:46 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[English]]></category>
		<category><![CDATA[Uni]]></category>
		<category><![CDATA[Use The Source]]></category>
		<category><![CDATA[c++]]></category>
		<category><![CDATA[python]]></category>
		<category><![CDATA[swig]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/archives/2007/10/calling-python-functions-from-swigc/</guid>
		<description><![CDATA[To make it more easy to integrate my Sparse Grid framework into existing applications (like those almighty financial applications where one function evaluation takes a whole day to calculate) and of course for easier development/testing, I searched for a way to call python callables from my swig-wrapped c++ code. Lets first have a look in [...]]]></description>
			<content:encoded><![CDATA[<p>To make it more easy to integrate my Sparse Grid framework into existing applications (like those almighty financial applications where one function evaluation takes a whole day to calculate) and of course for easier development/testing, I searched for a way to call python callables from my swig-wrapped c++ code.</p>
<p>Lets first have a look in the swig <a href="http://www.swig.org/Doc1.3/SWIG.html#SWIG_nn30">documentation</a>:</p>
<blockquote><p>SWIG provides full support for function pointers provided that the callback functions are defined in C and not in the target language.</p></blockquote>
<p>That&#8217;s unfortunate. Further <a href="http://www.google.com">research</a> revealed that there is indeed a (rather hackish) way to manage that.</p>
<p>First we define a function for setting the a callback:</p>
<blockquote><p>void setCallback(PyObject* obj) ;</p></blockquote>
<p>Now SWIG expects a wrapped PyObject-object, which we don&#8217;t have. That behavior can be overwritten be defining a custom typemap. The easiest possible solution would be:</p>
<blockquote><p>%typemap(in) PyObject* {<br />
$1 = $input;<br />
}</p></blockquote>
<p>All you have to do now is to check the object in your previously defined function and grab a reference to it. Read the <a href="http://docs.python.org/">Python documentation</a> on how to do that.</p>
<p>Overall rating: Working, but not very portable.</p>
]]></content:encoded>
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		<title>Sparse Grids</title>
		<link>http://www.4geeks.de/blog/archives/2007/03/sparse-grids/</link>
		<comments>http://www.4geeks.de/blog/archives/2007/03/sparse-grids/#comments</comments>
		<pubDate>Thu, 15 Mar 2007 23:27:05 +0000</pubDate>
		<dc:creator>ebo</dc:creator>
				<category><![CDATA[Uni]]></category>

		<guid isPermaLink="false">http://www.4geeks.de/archives/2007/03/sparse-grids/</guid>
		<description><![CDATA[Some screenshots from my latest project at the university. We have written a program that uses sparse grids to classify high-dimensional data. On the pictures you can see the interpolated function for two standard datasets (Ripley and checkerboard) plotted with Gnuplot. So much for the easy part of the assignment. For the next step we&#8217;ll [...]]]></description>
			<content:encoded><![CDATA[<p style="text-align: center;"><a href="http://www.4geeks.de/wp-content/uploads/2007/03/ripley-graph.png" rel="lightbox[pics-1173999879]" title="Ripley"><img src="http://www.4geeks.de/wp-content/uploads/2007/03/ripley-graph.thumbnail.png" width="200" height="132" alt="Ripley" class="imageframe imgaligncenter" /></a></p>
<p style="text-align: center;"><a href="http://www.4geeks.de/wp-content/uploads/2007/03/checkerboard-graph.png" rel="lightbox[pics-1173999879]" title="Checkboard"><img src="http://www.4geeks.de/wp-content/uploads/2007/03/checkerboard-graph.thumbnail.png" width="200" height="132" alt="Checkboard" class="imageframe imgaligncenter" /></a></p>
<p>Some screenshots from my latest project at the university. We have written a program that uses <a href="http://en.wikipedia.org/wiki/Sparse_grid">sparse grids</a> to classify high-dimensional data.</p>
<p>On the pictures you can see the interpolated function for two standard datasets (Ripley and checkerboard) plotted with Gnuplot. So much for the easy part of the assignment.</p>
<p>For the next step we&#8217;ll try to improve the method of computation, so it is possible to learn high-dimensional data even faster.</p>
]]></content:encoded>
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