SSH to server behind a firewall via an SSH tunnel

A server behind a firewall was unaccesible from my home, but another server which is on the same local network had public SSH access from my home. So we can create an SSH tunnel via this public server to the server behind a firewall.

For example the public ssh server …

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Recursive karatsuba multiplication in Python

I'm currently taking the class Algorithm: Design and Analysis of Stanford via Coursera and in the class the Karatsuba algorithm got mentioned. I went ahead and implemented it based on the lecture slides.

The Karatsuba algorithm is a fast multiplication algorithm. It's special because it was the first multiplication algorithm …

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Install PyQt in a virtualenv with Pip

Noticed that pip install pyqt isn't working? At least at the time of writing this blog it isn't..

This is the error that I got:
IOError: [Errno 2] No such file or directory: setup.py

It seems they didn't package it well and it's using configure.py to install. So …

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Only use worker when required on heroku with Django/Python

For a mobile project I required a background worker which sents an email with 300 generated QR codes zipped together as attachment. This costs quite some time so we need a background worker to execute this task.

I wanted to achieve the following result:

  • When the user wants to generate …
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