Wednesday, November 23, 2011

Cygwin git-svn messed up

I upgraded my Cygwin from version 1.5 to 1.7 (finally), and found that git-svn command was broken

$ git svn rebase
Can't locate SVN/ in @INC (@INC contains:
/usr/lib/perl5/site_perl/5.8 .) at /usr/lib/git-core/git-svn line 42.

Usually this error indicates that subversion-perl package is not installed, but that was not the case as we can see it from cygcheck output:

$ cygcheck -c subversion-perl
Cygwin Package Information
Package Version Status
subversion-perl 1.7.1-1 OK

As it turned out, the problem was in the package dependency management. From the error above we saw that perl was looking for SVN/ in /usr/lib/perl5/vendor_perl/5.14/i686-cygwin directory. But the latest subversion-perl installed it in the different place

$ cygcheck -l subversion-perl

The problem was solved by downgrading perl from 5.14.x-x to 5.10.x-x.

If you have the same problem, check which version of perl package you have installed

$ cygcheck -f /usr/bin/perl

It must be the same as the version used by subversion-perl.

Saturday, November 05, 2011

Ford Marbles

I found these marvelous renderings of Ford circles on flickr. I can't help but share them here.

As Thomae's function, Ford circles is another visual representation of rational numbers. You can investigate them here with interactive Wolfram demo.