Repository navigation
support for dfloat function, extension or standard? #1077
Description
This dfloat intrinsic function appears frequently in a DOE code. Here is a reduced test case that shows a canonical example of how it is used:
subroutine fwdcpfft_comp(psi, nr1, nr2, nr3)
implicit none
integer nr1, nr2, nr3
complex*16 psi(nr1, nr2, nr3)
real*8 fac
fac = 1.0d0/dfloat(nr1*nr2*nr3)
end
Is this part of the Fortran standard or an extension?
https://gcc.gnu.org/onlinedocs/gcc-4.4.1/gfortran/DFLOAT.html
https://software.intel.com/en-us/fortran-compiler-developer-guide-and-reference-dfloat
Is this really even necessary to have such an intrinsic? Wouldn't a compiler's type promotion heuristics automatically handle this?
Activity
klausler commentedon Mar 27, 2020
DFLOATis not a standard intrinsic procedure of Fortran.DBLE(n)andREAL(n,KIND=KIND(0.0d0))are standard equivalents for integern; so is(0.0d0+(n)). We'll probably supportDFLOATin f18 for better portability, but new code should avoid it.naromero77 commentedon Apr 2, 2020
Thanks for clarifying the correct way to do this. So far, I have only encountered this construct in one DOE code -- a rather old one at that.
If we are prioritizing non-standard extensions, it would be more important to get this one implemented
sizeof:#1020
As now I have found several DOE codes that make use of it.