https://gcc.gnu.org/onlinedocs/gfortran/ISO_005fFORTRAN_005fENV.htmlhas
real{32,64,128} that does a nice job for this situation.
Jeff
Sent from my iPhone
> On Sep 1, 2016, at 4:15 PM, Blaise A Bourdin <bour...@lsu.edu> wrote:
>
> Hi,
>
> If I recall correctly, fortran does not mandate that "selected_real_kind(5)"
> means the same across compilers, so that hardcoding kind values may not be
> portable.
>
>
> Instead, I would recommend the following (not my idea, it was proposed by
> Michael Metcalf in comp.lang.fortran a _long_ time ago) in a top-level module.
>
> ! The following ensures that mef90 and PETSC real types are compatible:
> ! thanks to Michael Metcalf in comp.lang.fortran
> PetscReal,Parameter :: PReal = 1.0
> Integer,Parameter,Public :: Kr =
> Selected_Real_Kind(Precision(PReal))
>
> PetscInt,Parameter :: PInt = 1
> Integer,Parameter,Public :: Ki = Selected_Int_Kind(PInt)
>
> PetscLogDouble,Parameter :: flop = 1.0
> Integer,Parameter,Public :: PFlop =
> Selected_Real_Kind(Precision(flop))
>
> so that Real(Kind = Kr) is the same as PetscReal, and literals can be written
> 1.234_Kr or 23_flop.
>
> I guess PETSc could define them in the petsc module and inherited from "use
> petsc”.
>
> Blaise
>
>
>
>> On Sep 1, 2016, at 5:37 PM, Barry Smith <bsm...@mcs.anl.gov> wrote:
>>
>>
>>> On Sep 1, 2016, at 5:28 PM, Munson, Todd <tmun...@mcs.anl.gov> wrote:
>>>
>>>
>>> Which platforms do not define PETSC_USE_FORTRANKIND?
>>
>> It uses it everywhere the Fortran compiler supports it.
>>
>> # reverse of the above - but more standard thing to do for F90 compilers
>> def checkFortranKind(self):
>> '''Checks whether selected_int_kind etc work USE_FORTRANKIND'''
>> self.pushLanguage('FC')
>> body = '''
>> integer(kind=selected_int_kind(10)) i
>> real(kind=selected_real_kind(10)) d
>> '''
>> if self.checkCompile('', body):
>> self.addDefine('USE_FORTRANKIND', 1)
>> self.popLanguage()
>> return
>>
>> Presumably any Fortran compiler that supports F90 supports it so it is not
>> unreasonable for us to just require it and simplify PETSc in a few places.
>>
>>
>>
>>
>>> Are they important
>>> or can we drop support for them?
>>>
>>> I could probably hack the D or Q for the others, but it would probably
>>> be ugly.
>>>
>>> Or I could just overrule my OCD today...
>>>
>>> Todd.
>>>
>>>> On Sep 1, 2016, at 5:08 PM, Barry Smith <bsm...@mcs.anl.gov> wrote:
>>>>
>>>>
>>>>> On Sep 1, 2016, at 4:37 PM, Munson, Todd <tmun...@mcs.anl.gov> wrote:
>>>>>
>>>>>
>>>>> Cool!
>>>>>
>>>>> For what its worth, that only works when PETSC_USE_FORTRANKIND is true.
>>>>> I'm not sure how many of the Petsc builds have this flag set.
>>>>
>>>> in the other case could you try to tack on the D or Q business?
>>>>
>>>> Barry
>>>>
>>>>>
>>>>> Any idea how to do the same thing in C?
>>>>>
>>>>> Todd.
>>>>>
>>>>>> On Sep 1, 2016, at 4:13 PM, Lisandro Dalcin <dalc...@gmail.com> wrote:
>>>>>>
>>>>>>
>>>>>> On 1 September 2016 at 23:05, Barry Smith <bsm...@mcs.anl.gov> wrote:
>>>>>> I didn't have a solution to this
>>>>>>
>>>>>> ! These lines should be added to
>>>>>> $PETSC_DIR/include/petsc/finclude/petscsysdef.h
>>>>>> #if defined(PETSC_USE_REAL_SINGLE)
>>>>>> integer, parameter :: PETSC_REAL_KIND = selected_real_kind(5)
>>>>>> #elif defined(PETSC_USE_REAL_DOUBLE)
>>>>>> integer, parameter :: PETSC_REAL_KIND = selected_real_kind(10)
>>>>>> #elif defined(PETSC_USE_REAL___FLOAT128)
>>>>>> integer, parameter :: PETSC_REAL_KIND = selected_real_kind(20)
>>>>>> #endif
>>>>>>
>>>>>> ! User code should write literals this way
>>>>>> PetscReal x
>>>>>> x = 0.123456789123456789123456789_PETSC_REAL_KIND
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Lisandro Dalcin
>>>>>> ============
>>>>>> Research Scientist
>>>>>> Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
>>>>>> Extreme Computing Research Center (ECRC)
>>>>>> King Abdullah University of Science and Technology (KAUST)
>>>>>> http://ecrc.kaust.edu.sa/
>>>>>>
>>>>>> 4700 King Abdullah University of Science and Technology
>>>>>> al-Khawarizmi Bldg (Bldg 1), Office # 0109
>>>>>> Thuwal 23955-6900, Kingdom of Saudi Arabia
>>>>>> http://www.kaust.edu.sa
>>>>>>
>>>>>> Office Phone: +966 12 808-0459
>
> --
> Department of Mathematics and Center for Computation & Technology
> Louisiana State University, Baton Rouge, LA 70803, USA
> Tel. +1 (225) 578 1612, Fax +1 (225) 578 4276
> http://www.math.lsu.edu/~bourdin
>
>
>
>
>
>
>
