[Numpy-discussion] Proposed Roadmap Overview
Sturla Molden
sturla@molden...
Mon Feb 20 09:29:46 CST 2012
Den 20.02.2012 08:35, skrev Paul Anton Letnes:
> In the language wars, I have one question. Why is Fortran not being considered? Fortran already implements many of the features that we want in NumPy:
Yes ... but it does not make Fortran a systems programming language.
Making NumPy is different from using it.
> - slicing and similar operations, at least some of the fancy indexing kind
> - element-wise array operations and function calls
> - array bounds-checking and other debugging aid (with debugging flags)
That is nice for numerical computing, but not really needed to make NumPy.
> - arrays that mentally map very well onto numpy arrays. To me, this spells +1 to ease of contribution, over some abstract C/C++ template
Mentally perhaps, but not binary. NumPy needs uniformly strided memory
on the binary level. Fortran just gives this at the mental level. E.g.
there is nothing that dictates a Fortran pointer has to be a view, the
compiler is free to employ copy-in copy-out. In Fortran, a function call
can invalidate a pointer. One would therefore have to store the array
in an array of integer*1, and use the intrinsic function transfer() to
parse the contents into NumPy dtypes.
> - in newer standards it has some nontrivial mathematical functions: gamma, bessel, etc. that numpy lacks right now
That belongs to SciPy.
> - compilers that are good at optimizing for floating-point performance, because that's what Fortran is all about
Insanely good, but not when we start to do the (binary, not mentally)
strided access that NumPy needs. (Not that C compilers would be any better.)
> - not Fortran as such, but BLAS and LAPACK are easily accessed by Fortran
> - possibly other numerical libraries that can be helpful
> - Fortran has, in its newer standards, thought of C interoperability. We could still keep bits of the code in C (or even C++?) if we'd like to, or perhaps f2py/Cython could do the wrapping.
Not f2py, as it depends on NumPy.
- some programmers know Fortran better than C++. Fortran is at least used by many science guys, like me.
That is a valid arguments. Fortran is also much easier to read and debug.
Sturla
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