Jose, This is great, thanks so much! Does Satish need to roll a new http://ftp.mcs.anl.gov/pub/petsc/externalpackages/f2cblaslapack-3.1.1.q.tar.... tar ball? I'm guessing yes? Barry On Aug 23, 2012, at 11:02 AM, "Jose E. Roman" <[email protected]> wrote:

El 22/08/2012, a las 18:52, Jose E. Roman escribió:

...

f2cblaslapack is more or less prepared for this case already (it is not much tested though, we will make some tests for the w* subroutines tomorrow).

What is not ready is PETSc itself. Some definitions are missing. For instance, PetscScalar is undefined, so one should add the following to petscmath.h:106:

#elif defined(PETSC_USE_REAL___FLOAT128) typedef __complex128 PetscScalar;

#define PetscRealPart(a) crealq(a) #define PetscImaginaryPart(a) cimagq(a) #define PetscAbsScalar(a) cabsq(a) #define PetscConj(a) conjq(a) #define PetscSqrtScalar(a) csqrtq(a) #define PetscPowScalar(a,b) cpowq(a,b) #define PetscExpScalar(a) cexpq(a) #define PetscLogScalar(a) clogq(a) #define PetscSinScalar(a) csinq(a) #define PetscCosScalar(a) ccosq(a)

Similarly, MPIU_SCALAR should be defined. Maybe other as well.

Jose

I have pushed a change to petsc-dev that allows to configure --with-precision=__float128 --with-scalar-type=complex

I have tested this with src/ksp/ksp/examples/tutorials/ex12.c with 1 and 2 processes. It seems to work.

Please review the change, since I had to modify pinit.c

A couple of comments:

1) The f2cblaslapack interface to quad precision subroutines (q* and w*) is defined only in the case of "uscore" mangling. Maybe a test in configure should assure this.

2) I could not make it work --with-clanguage=c++ - I get compilation errors like this. Any idea?

/usr/include/c++/4.6/complex: In function ‘_Tp std::__complex_abs(const std::complex<_Tp>&) [with _Tp = __float128]’: /usr/include/c++/4.6/complex:592:68: instantiated from ‘_Tp std::abs(const std::complex<_Tp>&) [with _Tp = __float128]’ /home/jroman/soft/petsc-dev/src/sys/utils/sortd.c:116:26: instantiated from here /usr/include/c++/4.6/complex:571:50: error: call of overloaded ‘abs(__float128&)’ is ambiguous /usr/include/c++/4.6/complex:571:50: note: candidates are: /usr/include/c++/4.6/cmath:82:3: note: double std::abs(double) /usr/include/c++/4.6/cmath:86:3: note: float std::abs(float) /usr/include/c++/4.6/cmath:90:3: note: long double std::abs(long double) /usr/include/c++/4.6/complex:571:50: error: call of overloaded ‘abs(__float128&)’ is ambiguous /usr/include/c++/4.6/complex:571:50: note: candidates are: /usr/include/c++/4.6/cmath:82:3: note: double std::abs(double) /usr/include/c++/4.6/cmath:86:3: note: float std::abs(float) /usr/include/c++/4.6/cmath:90:3: note: long double std::abs(long double) /usr/include/c++/4.6/complex:576:46: error: call of overloaded ‘sqrt(__float128)’ is ambiguous /usr/include/c++/4.6/complex:576:46: note: candidates are: /usr/include/x86_64-linux-gnu/bits/mathcalls.h:158:1: note: double sqrt(double) /usr/include/c++/4.6/cmath:416:3: note: float std::sqrt(float) /usr/include/c++/4.6/cmath:420:3: note: long double std::sqrt(long double)