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Van Rossum: Python Not Too Slow
snydeq writes "Python creator Guido van Rossum discusses the prospects and criticisms of Python, noting that critics of Python performance should supplement with C/C++ rather than re-engineering Python apps into a faster language. 'At some point, you end up with one little piece of your system, as a whole, where you end up spending all your time. If you write that just as a sort of simple-minded Python loop, at some point you will see that that is the bottleneck in your system. It is usually much more effective to take that one piece and replace that one function or module with a little bit of code you wrote in C or C++ rather than rewriting your entire system in a faster language, because for most of what you're doing, the speed of the language is irrelevant.'"
Python is strongly typed. Maybe you mean statically typed.
As someone simulating fluid-structure interaction with a number of constituent models and a lot of finite element (i.e. big matrix problems; using FEniCS - fenicsproject.org), using Python makes my overall quite-long algorithm much easier to flick through. Invaluable for debugging the theory as well as the implementation. FEniCS' Python interface ties into the standard C/C++ libraries using SWIG and, in simple cases, saves me working in C++. Very clear, well-written C++ is great for this application but I find it takes considerably longer to write than clear Python.
When I hit a more intricate problem, I realized I was going to have to solve a series of FE matrices by hand (with PETSc, written in C). It turned out to be pretty straightforward to pick up SWIG, write a short module in C and a Python interface. Done! Particularly useful as I believe getting FEniCS and petsc4py to play well is tricky.
So, I'd agree - having written a C++ version of my (simpler) problem and a Python/C version of the complicated one, the latter was definitely easier, and all the rate-limiting stuff is in C anyhow.
Doubt it would be true for every situation but +1 from an FE perspective.
Yes, that is correct. You should write your apps in Python.
Your libraries, you should write in Python first, because it is also a great prototyping language. If they work fine (which they will in most cases) you have saved yourself a bunch of time. If they are too slow, you have saved yourself a bunch of time by fixing algorithmic bugs in a flexible language like Python. It is now trivial to convert it to bug-free C or C++.
If it's in you sig, it's in your post.
[Python is sometimes faster to write in.]
Python isn't just fast to write though - it's fast and easy to read and understand, to work with, and it's very easy to keep code clear and well documented. I'm not saying these things are impossible in other languages, but in Python it is effortless, and enocouraged by the language. There are big benefits to using it besides simply 'fast to write'.
-- Lattyware (www.lattyware.co.uk)