[Bug fortran/27452] gfortran support for non-standard sind,cosd and friends intrinsics

["ruben at tapir dot caltech dot edu" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #8 from ruben at tapir dot caltech dot edu  2009-04-30 07:33 -------
In my considered opinion, the need to support these functions has little to do
with efficiency or with convenience.  It has more to do with accuracy and
symmetries; relations such as sind(30)=0.5, cosd(90)=0.0, and such must be
fulfilled exactly, and that without damaging finite-differencing properties. 
Relations such as sind(x)=cosd(90-x) may also be fulfilled to sufficient
accuracy - and maybe even exactly.  These things are difficult or impossible to
achieve using radian units, giving niche use to the degree-based functions for
applications where high floating point accuracy of symmetries must be
preserved.  Angular grids in curvilinear CFD occassionally need that.  There
must be other examples.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27452