[Numpy-discussion] Specifying compiler command line options for numpy.disutils.core
david at ar.media.kyoto-u.ac.jp
Fri Jun 15 00:01:21 EDT 2007
Matthieu Brucher wrote:
> I think the default for the standard python distutils is to use the
> compiler and the compiler settings for the C compiler that were
> used to
> build Python itself. There might be ways to specify other
> compilers; but
> if you have a shared python library build with one compiler and
> build with another you might run into trouble if the two compilers
> different system libraries which are not resolved by standard python
> Well, the Intel compiler uses the same libraries than gcc on Linux,
> and on Windows, I don't know, but it is possible to mix VS2003 and
> VS2005, whuch is forbidden by the distutils, so I find this too
> restricting although understandable.
It is possible to mix object code, but not runtime, which is the problem
AFAIK. VS2003 and VS2005 have different C runtimes (msvcrt7.1.dll
against msvcrt8.dll). The problem is (at least for me, who just go
through the pain for windows users :) ) that VS2003 is not available
anymore for free...
> I believe that numpy is similar in the sense that you can always build
> additional modules with the compilers that were used to build the
> core; then, using two fortran based modules (say) will work well
> both require the same shared system libraries of the compiler.
> the compiler options used to build numpy will also work for your
> additinal modules (with respect to paths to linear algebra
> libraries and
> so on).
> No, in this case, I want to build with icc and special compiler
> options. I tried by build by hand - and CMake - the libraries, it
> works like a charm and it is very very fast compared to gcc :(
Which libraries are you talking about ? Also, beware that ICC uses by
default some flags which are potentially dangerous (I don't know if this
is true anymore, but ICC used to use the equivalent of --ffast-math of
gcc by default:
For libraries like atlas, I don't think there will be a huge difference
between ICC and gcc; if you use the mkl, then you don't care :)
> Again, I think there could be ways to build with different
> compilers, but
> you do run the risk of incompatibilities with the shared libraries.
> Therefore, I have become used to build python with the C-compiler kI'd
> like to use, even if that means a lot of work.
> This would mean building every other modules added - numpy, scipy,
> matplotlib, wxPython, ... -, doable, but I'd prefer not to do it, but
> if it is not possible, I would have to live with it...
I think it is important to separate different issues: object code
compatibility, runtime compatibility, etc... Those are different issues.
First, mixing ICC compiled code and gcc code *has* to be possible (I
have never tried), otherwise, I don't see much use for it under linux.
Then you have the problem of runtime services: I really doubt that ICC
runtime is not compatible with gcc, and more globally with the GNU
runtime (glibc, etc...); actually, ICC used to use the "standard" linux
runtime, and I would be surprised if that changed.
To say it simply: on linux at least, what should matter is whether the
runtime services are compatible (on windows, it looks like they are not:
official python is compiled with visual studio 2003, and you cannot use
VS 2005; note that mingw seems to work).
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