Given argument returns .
interface normalizeVector function normalizeVectorSingle(argument) real(single), intent(in) :: argument(:) real(single) :: normalizeVectorSingle(size(argument)) end function normalizeVectorSingle function normalizeVectorDouble(argument) real(double), intent(in) :: argument(:) real(double) :: normalizeVectorDouble(size(argument)) end function normalizeVectorDouble end interface