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yes it was very eye opening. i often see people comparing their favourite package manager to pythons and coming to the conclusion that python is terrible, but i

yes it was very eye opening. i often see people comparing their favourite package manager to pythons and coming to the conclusion that python is terrible, but its not! one thing i dont quite understand, is why dont the python people just use a c/c++ math library instead of fortran?

patrick451 3y ago
There often simply doesn't exist an equivalent library written in c/c++ (or any other language for that matter). The example I'm familiar with is SLICOT (Subroutine Library in Systems and Control Theory) [1], exposed in python through Slycot [2]. It as routines for pole placement, riccati solvers, various factorizations, and MIMO zero computations and a ton of other stuff. As far as I have been able to find, no c/c++/other-language comes close to supplying either the breadth or depth of this library. Further, many of the SLICOT subroutines were written by the original inventors of their respective algorithms, which I view as a big bonus. [1] http://slicot.org/ http://slicot.org/ [2] https://github.com/python-control/Slycot https://github.com/python-control/Slycot
- avidphantasm 3y ago
  Right, lots of legacy code, plus lack of pointer aliasing in Fortran opens up more opportunities for optimization (or so I have read; this might have changed).
  - rightbyte 3y ago
    'restrict' has been an common extension in C since long ago and is now a proper keyword. I guess it is a matter of taste.
    - baq 3y ago
      also a matter of 'I'm not going to rewrite lapack in C because a platform which was never the intended target doesn't have a free compiler'.
- radarsat1 3y ago
  A lot of these kinds of routines could be translated to other languages but aren't because they are complex and often unmaintained and no one is really around that understands them well enough to port them to C or Rust or whatever. There is also the issue that often they were published before adding a LICENSE file was a thing. I've found myself in the position before of having to email professors in some random university to ask them if I can get permission to redistribute such a routine while packaging a library that depended on it. In one case I asked them if it would be possible to update their code with a license (which was just a zip file on netlib) and the answer was, "no, but you have my email". So I found myself having to write something like "distributed with permission from the author, private correspondence, pinky swear" in my copyright file. some of this code is so old the authors aren't around and it would get "lost" in terms of being able to get permissions to use it, I mean it's a potential crisis to be honest, if people really cared to check. (Until the copyrights expire I guess, which is what, 70 years after the author's death or some such?) Anyway, I wonder if a potential solution is to autotranslate some of these libraries using LLMs? Maybe AI will save us in the end. Of course you can't trust LLMs so you still need to understand the code well enough to verify any such translation.
  - BlueTemplar 3y ago
    > (Until the copyrights expire I guess, which is what, 70 years after the author's death or some such?) «To promote the Progress of Science and useful Arts», my ass. Why do we keep tolerating this Disney-caused bullshit ? Though I guess that we didn't, and this is what caused the Free Software movement, so it all works out in the end ?
ecshafer 3y ago
Imo i would much rather write a math library in fortran than c or cpp. Fortran is quite a joy for doing numerical work. It sucks for most other things though. Really the only thing nowadays is that youll probably be using gpus so that makes cpp better for cuda integration.
- BlueTemplar 3y ago
  Why would C++ be better than FORTRAN for GPUs ?
dzdt 3y ago
Because some of the best math libraries are written in Fortran. Seriously lots of heavy duty scientific code was written in Fortran in the 1970s and is still underpinning applications today. In many cases there is no equivalent alternative.

patrick451 3y ago

There often simply doesn't exist an equivalent library written in c/c++ (or any other language for that matter). The example I'm familiar with is SLICOT (Subroutine Library in Systems and Control Theory) [1], exposed in python through Slycot [2]. It as routines for pole placement, riccati solvers, various factorizations, and MIMO zero computations and a ton of other stuff. As far as I have been able to find, no c/c++/other-language comes close to supplying either the breadth or depth of this library. Further, many of the SLICOT subroutines were written by the original inventors of their respective algorithms, which I view as a big bonus. [1] http://slicot.org/ http://slicot.org/ [2] https://github.com/python-control/Slycot https://github.com/python-control/Slycot

avidphantasm 3y ago
Right, lots of legacy code, plus lack of pointer aliasing in Fortran opens up more opportunities for optimization (or so I have read; this might have changed).
- rightbyte 3y ago
  'restrict' has been an common extension in C since long ago and is now a proper keyword. I guess it is a matter of taste.
  - baq 3y ago
    also a matter of 'I'm not going to rewrite lapack in C because a platform which was never the intended target doesn't have a free compiler'.
radarsat1 3y ago
A lot of these kinds of routines could be translated to other languages but aren't because they are complex and often unmaintained and no one is really around that understands them well enough to port them to C or Rust or whatever. There is also the issue that often they were published before adding a LICENSE file was a thing. I've found myself in the position before of having to email professors in some random university to ask them if I can get permission to redistribute such a routine while packaging a library that depended on it. In one case I asked them if it would be possible to update their code with a license (which was just a zip file on netlib) and the answer was, "no, but you have my email". So I found myself having to write something like "distributed with permission from the author, private correspondence, pinky swear" in my copyright file. some of this code is so old the authors aren't around and it would get "lost" in terms of being able to get permissions to use it, I mean it's a potential crisis to be honest, if people really cared to check. (Until the copyrights expire I guess, which is what, 70 years after the author's death or some such?) Anyway, I wonder if a potential solution is to autotranslate some of these libraries using LLMs? Maybe AI will save us in the end. Of course you can't trust LLMs so you still need to understand the code well enough to verify any such translation.
- BlueTemplar 3y ago
  > (Until the copyrights expire I guess, which is what, 70 years after the author's death or some such?) «To promote the Progress of Science and useful Arts», my ass. Why do we keep tolerating this Disney-caused bullshit ? Though I guess that we didn't, and this is what caused the Free Software movement, so it all works out in the end ?

ecshafer 3y ago

Imo i would much rather write a math library in fortran than c or cpp. Fortran is quite a joy for doing numerical work. It sucks for most other things though. Really the only thing nowadays is that youll probably be using gpus so that makes cpp better for cuda integration.

BlueTemplar 3y ago
Why would C++ be better than FORTRAN for GPUs ?

dzdt 3y ago

Because some of the best math libraries are written in Fortran. Seriously lots of heavy duty scientific code was written in Fortran in the 1970s and is still underpinning applications today. In many cases there is no equivalent alternative.