http://www.stringwiki.org/w/api.php?action=feedcontributions&user=Arivero&feedformat=atomString Theory Wiki - User contributions [en]2024-03-28T18:22:49ZUser contributionsMediaWiki 1.39.1http://www.stringwiki.org/w/index.php?title=Blogs&diff=2074Blogs2008-03-15T00:43:59Z<p>Arivero: </p>
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<div>[http://fliptomato.wordpress.com/ An American Physics Student in England]<br><br />
by Philip Tanedo<br />
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[http://asymptotia.com/ Asymptotia]<br><br />
by Clifford V. Johnson<br />
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[http://atdotde.blogspot.com/ atdotde]<br><br />
by Robert Helling<br />
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[http://cosmicvariance.com/ Cosmic Variance]<br><br />
by various<br />
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[http://imaginarypotential.wordpress.com/ Imaginary Potential]<br><br />
by various<br />
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[http://golem.ph.utexas.edu/~distler/blog/ Musings]<br><br />
by Jacques Distler<br />
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[http://www.math.columbia.edu/~woit/wordpress/ Not Even Wrong]<br><br />
by Peter Woit<br />
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[http://insti.physics.sunysb.edu/~siegel/parodies/atchoo.html "The Official String Blog"]<br><br />
by Warren Siegel<br />
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[http://ppcook.blogspot.com/ P.P. Cook's Tangent Space]<br />
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[http://motls.blogspot.com/ The Reference Frame]<br><br />
by Lubos Motl<br />
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[http://golem.ph.utexas.edu/string/ The String Coffee Table]<br><br />
by various<br><br />
this blog requires that your browser speaks MathML<br />
<br />
[http://math.ucr.edu/home/baez/this.week.html This Week's Finds in Mathematical Physics]<br><br />
by John Baez</div>Ariverohttp://www.stringwiki.org/w/index.php?title=User:Arivero&diff=2073User:Arivero2008-03-15T00:43:15Z<p>Arivero: </p>
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<div>[http://dftuz.unizar.es/~rivero/]</div>Ariverohttp://www.stringwiki.org/w/index.php?title=Blogs&diff=2072Blogs2008-03-15T00:42:40Z<p>Arivero: </p>
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<div>[http://fliptomato.wordpress.com/ An American Physics Student in England]<br><br />
by Philip Tanedo<br />
<br />
[http://asymptotia.com/ Asymptotia]<br><br />
by Clifford V. Johnson<br />
<br />
[http://atdotde.blogspot.com/ atdotde]<br><br />
by Robert Helling<br />
<br />
[http://cosmicvariance.com/ Cosmic Variance]<br><br />
by various<br />
<br />
[http://imaginarypotential.wordpress.com/ Imaginary Potential]<br />
by various<br />
<br />
[http://golem.ph.utexas.edu/~distler/blog/ Musings]<br><br />
by Jacques Distler<br />
<br />
[http://www.math.columbia.edu/~woit/wordpress/ Not Even Wrong]<br><br />
by Peter Woit<br />
<br />
[http://insti.physics.sunysb.edu/~siegel/parodies/atchoo.html "The Official String Blog"]<br><br />
by Warren Siegel<br />
<br />
[http://ppcook.blogspot.com/ P.P. Cook's Tangent Space]<br />
<br />
[http://motls.blogspot.com/ The Reference Frame]<br><br />
by Lubos Motl<br />
<br />
[http://golem.ph.utexas.edu/string/ The String Coffee Table]<br><br />
by various<br><br />
this blog requires that your browser speaks MathML<br />
<br />
[http://math.ucr.edu/home/baez/this.week.html This Week's Finds in Mathematical Physics]<br><br />
by John Baez</div>Ariverohttp://www.stringwiki.org/w/index.php?title=Maxima&diff=1974Maxima2007-10-28T10:44:41Z<p>Arivero: /* plotting with Maxima */</p>
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<div>[http://maxima.sourceforge.net/ Maxima] is an open source computer algebra system, similar to Mathematica. It is available for GNU/Linux, MacOS X and Windows.<br />
<br />
===installation on a GNU/Linux system===<br />
There should be pre-compiled packages available for most distributions. For example in Debian-based distributions such as [http://www.ubuntu.com/ Ubuntu] install the maxima and maxima-share packages by typing<br />
<pre><br />
sudo apt-get install maxima maxima-share<br />
</pre><br />
<br />
===sample usage===<br />
<pre><br />
expand((x+y+z)^4);<br />
integrate(1/(1+x^3),x);<br />
</pre><br />
<br />
===tensor manipulation===<br />
The [http://maxima.sourceforge.net/docs/manual/en/maxima_28.html ctensor module] is useful for tensor manipulation (in Ubuntu GNU/Linux this is included in the maxima-share package).<br />
<br />
Sample usage:<br />
<pre><br />
load(ctensor);<br />
dim: 5;<br />
ct_coords: [t,rho,chi1,chi2,chi3];<br />
lg: matrix([-(R^2)*(cosh(rho)^2),0,0,0,0],[0,R^2,0,0,0],[0,0,(R^2)*(sinh(rho)^2),0,0],[0,0,0,(R^2)*(sinh(rho)^2)*sin(chi1)^2,0],[0,0,0,0,(R^2)*(sinh(rho)^2)*(sin(chi1)^2)*(sin(chi2)^2)]);<br />
cmetric();<br />
ug;<br />
christof(mcs);<br />
ricci(true);<br />
scurvature();<br />
trigsimp(%);<br />
</pre><br />
This finds the Christoffel symbols, the Ricci tensor and the Ricci curvature scalar of the 5-dimensional Anti de Sitter spacetime metric.<br />
<br />
===plotting with Maxima===<br />
Maxima integrates well with [http://www.gnuplot.info/ gnuplot] to provide graph plotting. (Note that in Ubuntu GNU/Linux you need the addition package gnuplot-x11 or the GUI wxMaxima to use gnuplot's full graphical output) <br />
<br />
A selection of examples:<br />
<pre><br />
plot2d(sin(x),[x,0,10]);<br />
plot2d([parametric, (1+cos(t))*cos(t), (1+cos(t))*sin(t), [t,-%pi,%pi], [nticks,80]],[x, -1,2]);<br />
plot3d (atan (-x^2 + y^3/4), [x, -4, 4], [y, -4, 4], [grid, 50, 50]);<br />
</pre><br />
For more examples see [http://maxima.sourceforge.net/docs/manual/en/maxima_8.html Maxima manual: plotting].<br />
<br />
===integration with GNU Emacs===<br />
There is a Maxima-mode for GNU Emacs. For Ubuntu GNU/Linux simply install the maxima-emacs package. So that GNU Emacs knows to use this mode when you edit files with the .max extension, add the following lines to your .emacs file in your home directory:<br />
<pre><br />
(setq auto-mode-alist (cons '("\\.max" . maxima-mode) auto-mode-alist))<br />
(setq load-path (cons "/usr/share/maxima/5.9.2/emacs" load-path ))<br />
(autoload 'maxima "maxima" "Running Maxima interactively" t)<br />
(autoload 'maxima-mode "maxima" "Maxima editing mode" t)<br />
</pre><br />
<br />
===links===<br />
[http://maxima.sourceforge.net/ Maxima website]<br />
<br />
[http://maxima.sourceforge.net/docs/manual/en/maxima.html Maxima manual]<br />
<br />
[http://maxima.sourceforge.net/docs/tutorial/en/gaertner-tutorial-revision/Contents.htm Maxima tutorial]<br />
<br />
[http://maxima.sourceforge.net/docs/intromax/intromax.html Introduction to Maxima]</div>Arivero