Editing Numerical Recipes (section)

=== License ===
The code listings are copyrighted and commercially licensed by the ''Numerical Recipes'' authors.<ref>Numerical Recipes Web site, [https://numerical.recipes/licenseinfo.html Numerical Recipes Code]</ref> A license to use the code is given with the purchase of a book, but the terms of use are highly restrictive.<ref>{{cite web |last1=Weiner |first1=Benjamin |title=Boycott Numerical Recipes |url=http://mingus.as.arizona.edu/~bjw/software/boycottnr.html |quote=Buy the book if you feel like it, learn from it, but use a library like the GNU Scientific Library instead. Especially if you ever want other people to use your work. The NR license is the RIAA of the scientific community.}}</ref> For example, programmers need to make sure NR code cannot be extracted from their finished programs and used &ndash; a difficult requirement with dubious enforceability.<ref>{{cite tech report |first=Haysn |last= Hornbeck |title=Fast Cubic Spline Interpolation |arxiv=2001.09253 |institution=University of Calgary |date=January 28, 2020 }}</ref>

However, ''Numerical Recipes'' does include the following statement regarding copyrights on computer programs:<blockquote>Copyright does not protect ideas, but only the expression of those ideas in a particular form. In the case of a computer program, the ideas consist of the program's methodology and algorithm, including the necessary sequence of steps adopted by the programmer. The expression of those ideas is the program source code{{nbsp}}... If you analyze the ideas contained in a program, and then express those ideas in your own completely different implementation, then that new program implementation belongs to you.<ref name="ThirdEdition" /></blockquote> 

One early motivation for the [[GNU Scientific Library]] was that a [[free software|free]] library was needed as a substitute for ''Numerical Recipes''.<ref name=gsl>{{cite web |last1=Galassi |first1=Mark |last2=Theiler |first2=James |last3=Gough |first3=Brian |title=GNU Scientific Library -- Design document |url=https://www.gnu.org/software/gsl/design/gsl-design.html |website=GNU Operating System |publisher=GNU.org |access-date=January 5, 2019}}</ref>