[petsc-dev] fortran literals

[Munson, Todd]

Did we come to a conclusion on this?  Is it worthwhile adding macros for C and 
Fortran literals to make sure they match the PetscScalar type along with the 
appropriate configure tests?

Todd.

> On Sep 3, 2016, at 3:18 PM, Lisandro Dalcin <dalcinl at gmail.com> wrote:
> 
> 
> On 2 September 2016 at 00:46, Scott Kruger <kruger at txcorp.com> wrote:
> Lisandro's description is the most natural way for a modern fortran programmer.
> 
> But for completeness, this is equivalent:
>    x=REAL(0.123456789123456789123456789,KIND=PETSC_REAL_KIND)
> 
> I think you are wrong. The literal gets demoted to single precision, so you loose digits.
> 
> $ cat tmp.f90
> program main
>   real(kind=8) x
>   x = REAL(0.123456789123456789123456789,KIND=8)
>   write (*,'(F18.16)') x
>   x = 0.123456789123456789123456789_8
>   write (*,'(F18.16)') x
> end program main
> 
> $ gfortran tmp.f90
> $ ./a.out 
> 0.1234567910432816
> 0.1234567891234568
> 
> 
> -- 
> Lisandro Dalcin
> ============
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