I just released version 1.3 of my scalar package in Python. This package implements scalar physical units (meters, seconds, feet, degrees, etc.). It eliminates unit errors, a common source of bugs in engineering and scientific applications. The entire SI (metric) system is implemented, plus many other common units. You can also easily define your own smaller set of units for specific applications or domains. The advantage of my implementation over others, I believe, is that it allows the user to easily switch off the unit checks for efficient production runs. This speeds up the processing dramatically (by well over an order of magnitude), making it virtually as efficient as using built-in numeric types (without changing the output, of course). It's free, and it comes with a complete user guide (in both pdf and html). Take a look at it. I think you'll like it. I think it's well written, but I would also be interested in any feedback on code quality from Python experts. You can get it at http://RussP.us/scalar.htm