[Numpy-discussion] Anyone have a well-tested SWIG-based C++ STL valarray <=> numpy.array typemap to share?

Alexander Schmolck a.schmolck@gmx....
Thu Sep 20 07:57:06 CDT 2007


"Charles R Harris" <charlesr.harris@gmail.com> writes:

> The automatic handling of pointers for the default allocation type is also
> convenient and makes it reasonable to have functions return matrices and
> vectors.

Hmm, I wonder whether I missed something when I read the manual. I didn't see
anything in the docs that suggests that ublas matrices do COW, reference
semantics or anything else to make C++'s horrible pass-by-value semantics
bearable performancewise, so I return and pass in shared_ptr's to matrices,
which is syntactically ugly but avoids the need to write a (reference
semantics) wrapper class for matrix. Am I missing some easier way to
efficiently return and pass large matrices?

'as


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