acos - Calculate the arc cosine of double number.
double acos -> double
1.0 acos -> 0.0
Alternatives: Function acos_d (undocumented)
-> behaviour and synopsis are the same.
Diesmann
090225
/home/abuild/rpmbuild/BUILD/nest-2.20.git-build/nest-2.20.git/sli/slimath.cc