Author Archives: Bojan

Create a symmetric matrix in Mathematica

Here is a quick way to create a symmetric matrix in Mathematica. The code below creates a generic 6×6 matrix (line 1), then mirrors the above-diagonal elements to their below-diagonal counterparts (substitution in lines 3-5). am = Array[Subscript[a,##] &, {6,6}]; am = am /. Flatten[Table[ Subscript[a,i,j] -> Subscript[a,j,i], {i,2,6}, {j,1,i-1}]]
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ezproxy redirect bookmarklet

A while ago I wrote a Google Toolbar button for redirecting the current page to the same page accessed through an EZproxy server. As I was missing this functionality in browsers without Google Toolbar (it’s still not available in Google Chrome), I realized that it’s a very simple thing to do with a bookmarklet. Here [...]
Posted in Papers, Tips & Tricks, Web | Tagged , | Leave a comment

Hello WordPress!

If there is a good thing about having a cold/flu it’s that you get around to do those little things you’ve been putting off for months or years (because you’re not up for much else) — like getting your blog in order. I’ve used Blogger some time ago, then installed WordPress, but never moved old [...]
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.bst file for the International Journal of Non-Linear Mechanics

As I was writing my compacton paper, I needed to format my references following the International Journal of Non-Linear Mechanics style. So I wrote a .bst (BibTeX bibliographic style) file that gives pretty much the desired output: ijnlm.bst.
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Caffeine triggered migraine

This is an interesting article on caffeine and migraine. I thought the connection was obvious, I had no idea it is something still debated/not explicitly shown in studies.
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XML parsing with Perl using XPath

use strict; use XML::LibXML; # data source my $xml_filename = "xml/data.xml"; my $parser = XML::LibXML->new; my $doc = $parser->parse_file($xml_filename); my $xpath = "//word/entry[\@src=\"pr\"]/.."; my @words = $doc->findnodes($xpath); foreach my $word (@words) { print $word->findvalue("\@id"); print "\n"; }
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File modified timestamp with Perl

This is how to quickly get the timestamp of when the file was last modified in Perl: $lastmod = (stat($filename))[9];
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XSLT transform with Perl

Here is a Perl snippet that transforms an XML file with XSLT: use strict; use XML::XSLT::Wrapper; my $xml_input_filename = "xml/data.xml"; my $xml_output_filename = "xml/out.xml"; my $xsl_filename = "xml/transform.xslt"; my $xslt = XML::XSLT::Wrapper->new( ProcessorList => [ 'libxslt', 'sablotron', 'xslt' ], ); my $result = $xslt->transform( OutFile => $xml_output_filename, xml => $xml_input_filename, xsl => $xsl_filename, ); $xslt->dispose();
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Blogger, WordPress, b2evolution: Blog Engine Choice

As I signed up with Blogger a few years ago, and have never looked at alternatives, I decided to do so now, just to check whether I'm missing on something. Here's what I found.

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Sitemap generator configuration for Blogger

If you are using Google’s sitemap generator [code]]czoxNDpcInNpdGVtYXBfZ2VuLnB5XCI7e1smKiZdfQ==[[/code] to generate a sitemap of your Blogger blog , here are the configuration lines to add to the config.xml file:
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