[SciPy-dev] Numerical Recipes (was tagging 0.7rc1 this weekend?)

Stéfan van der Walt stefan@sun.ac...
Fri Dec 19 16:41:20 CST 2008

2008/12/16 Jarrod Millman <millman@berkeley.edu>:
> 4.  3 functions in scipy/stats/stats.py.
> Partially resolved.  One down (Josef rewrote ks_2samp), two left
> (ttest_ind and ttest_rel).

>From the NR license:

"""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 (particularly any
arbitrary or stylistic choices embodied in it), its derived object
code, and any other derivative work.

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.  That is what we have done
for those programs in this book that are not entirely of our own
devising.  When programs in this book are said to be "based" on
programs published in copyright sources, we mean that the ideas are
the same.  The expression of these ideas as source code is our own.
We believe that no material in this book infringes on an existing

I am not convinced that their interpretation of copyright law is
correct, but either way I think ttest_ind and ttest_rel are safe
(according to *their* rules).  The code makes use of constructs such
as "where" and broadcasting, that aren't available in C.  The author
therefore took an idea from NR and reimplemented it in a novel way.


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