[sampo]

> it's better to pick a different book

In my experience and opinion, Numerical Recipes hits a pretty unique spot by explaining enough about the ideas behind and how the algorithms work, that one can start implementing them (with or without reading the code) but not getting theory-heavy and full of equations and proofs, like a real numerical analysis textbook.

Kahaner, Moler, Nash: Numerical Methods and Software is a similar book, maybe even better, but it's from 1988 and never updated, and it's not nearly as widely known. Also it covers a smaller range of topics.

[FabHK]

The point stands, though - NR gives a nice introduction, and allows you to dabble with code and algorithm. But the NR code is didactic, it is not production quality (nor is it intended as such). Together with the restrictive license terms, that means:

For anything to be used in the real world, in production, you're better off taking code from somewhere else.

What alternative to use depends on the topic/algorithm in question. But NR should just be a starting point, not what you actually use.