LAPACK/ScaLAPACK Development

---> IDENTICAL C++/LAPACK CODE WORKS WELL ON WINDOWS AND FAILS TO COMPILE ON LINUX - POSSIBLE CULPRIT COMPLEX VALUES DECLARATIONS IN LAPACKE AND ORDINARY C++ <---

I've developed code in C++ with LAPACKE and MPI on a Windows machine where the code compiles and works well. When I migrated the code to Linux(CentOS) server, the code failED to compile! The possible culprit is complex values declaration (in various forms). Details are listed below, please help!

--The code works well on Windows with GNU C++ version 4.9.2., Lapack/LAPACKE and MS MPI (MPICH2).

--The code does NOT compile on CentOS LINUX server. GNU C++ version is 4.4.7; MPI(MPICH2) works well on this Linux machine (tested with C++ codes without LAPACKE). The LAPACKE libraries I use on Windows are the same ones I use on Linux.

The errors I get when compiling on the Linux machine are related to declarations of complex values (scalars, arrays), and typically they are like this one error: expected unqualified-id before '__complex__'. Upon inspecting preprocessor output on both Win and Linux machines, I've noticed following (for example):

If in the original source code you have declaration lapack_complex_double* HAMILTONIAN;, then
on the Windows machine you would see _lapack_complex_double* HAMILTONIAN; (which works well on Windows) and
on the Linux machine you would see double _Complex* HAMILTONIAN; which consequently gives error message during compilation stage.

More generally, I can see that the reported compilation errors on the Linux machine are pointing to places where complex in the original source is translated as _Complex in the preprocessor file, for the case of ordinary C++ variable; and for the case of LAPACKE variables when lapack_complex_double in the original source is translated as double _Complex. So, it seems like the problem is that compiler wrongly translates complex C++ type and similar LAPACKE types like lapack_complex_double[\b]. I've tried [b]#define _Complex complex , but (as expected) it didn't work - it solved problems on some places and created new problems on the other places.

Did you have experience with THE SAME or SIMILAR problem? Please help.

Thanks so much.

No expert in all this, but the lines
_lapack_complex_double* HAMILTONIAN;
or
double _Complex* HAMILTONIAN;
do not read to LAPACK to me. So I guess you have a second package involved in the mix.

I assume you are using LAPACK inside another specialized package and I would say that the problem comes at the interface of this package and LAPACK.

LAPACK has complex numbers defined as lapack_complex_double on Windows and so it seems that complex numbers are defined as lapack_complex_double for `HAMILTONIAN`. And so it works fine on Windows.

Then on Linux, it seems that LAPACK's complex numbers are defined as lapack_complex_double, while defined as _Complex* for `HAMILTONIAN`, and so this crashes.

I think you will need to set some compilation flags in the second package, maybe edit the code, so that this matches.

Julien.

Thanks Julien for your input. Here is my current update on this problem.

The issue is most likely in declarations of C vs. C++ complex entities. On this link http://stackoverflow.com/questions/2341 ... -same-file it is said that "g++ does since 4.8 to support both <complex> and <complex.h> in the same translation unit." I think that is the issue here. I've tried #define complex _Complex but it creates more errors than it resolves. The GCC on the CentOS machine is ver. 4.4.7 and the one where I developed the code (Windows machine) is 4.9.2. The request has been put to the root/admin to updated the GCC on CentOS. I'll post the results once that is done.
In the meantime, if you or anyone reading had more ideas/info about this issue, I would greatly appreciate to post it here.
Have a nice weekend!!!