[petsc-users] complex number issues

[Satish Balay]

I don't understand the code change - but if you want to use c99
complex - you can build petsc with:

--with-scalar-type=complex --with-clanguage=c [which is the default for clanguage]

And no code-change needed for PETSc. However if your code uses c++ -
you might have to address that..

Satish

On Wed, 19 May 2010, RenZhengYong wrote:

> Hi,  PETSc team,
> I wrote a C++ code dealing with electromagnetic problems, which can smoothly
> call PETSc complied by using " --with-scalar-type=complex
> --with-clanguage=cxx" .
> To improve the performances of the C++ code, I changed the complex number of
> type from std::complex<double> to double _Complex (C99 standard, roughly
> 30~50 times faster compared to std::complex<double>). But when I find that
> the C99 complex number head file <complex.h> will lead to the following
> kinds of errors"
> 
> /usr/include/c++/4.3/complex:57: error: expected identifier before
> ‘__complex__’
> /usr/include/c++/4.3/complex:58: error: expected identifier before
> ‘__complex__’
> /usr/include/c++/4.3/complex:58: error: expected unqualified-id before ‘<’
> token
> /usr/include/c++/4.3/complex:59: error: expected identifier before
> ‘__complex__’
> /usr/include/c++/4.3/complex:59: error: expected unqualified-id before ‘<’
> token
> /usr/include/c++/4.3/complex:60: error: expected identifier before
> ‘__complex__’
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:157: error:
> expected unqualified-id before ‘__complex__’
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:306: error:
> ‘PetscScalar’ does not name a type
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:339: error:
> ‘PetscScalar’ does not name a type
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: warning:
> ‘PetscGlobalSum’ initialized and declared ‘extern’
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: error:
> ‘PetscScalar’ was not declared in this scope
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: error:
> expected primary-expression before ‘,’ token
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: error:
> ‘PetscScalar’ was not declared in this scope
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: error:
> expected primary-expression before ‘,’ token
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: error:
> expected primary-expression before ‘)’ token
> /home/Zhengyong/packages/petsc-3.1-p1/include/petscmath.h:469: error:
> initializer expression list treated as compound expression
> 
> 
> Could you please give me some idea to deal with these problems?
> 
> Kind regards,
> Zhengyong Ren
> 
>