/usr/share/doc/ruby-gsl/examples/integration/qag3.rb is in ruby-gsl 2.1.0.3+dfsg1-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | #!/usr/bin/env ruby
require("gsl")
include Math
f = GSL::Function.alloc { |x| x*sin(1.0/x)*sqrt((1 - x).abs) }
w = GSL::Integration::Workspace.alloc(1000)
p f.qag(0, 3, w)
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