CONVENTIONS

Code conventions used internally by NFFT3 (not in API):

   Common names:

   R          : real type, (typically fftw_real)
   E          : real type for local variables (possibly extra precision)
   C          : complex type
   A          : assert
   CK         : check
   X(...)     : used for mangling of external names (see below)
   Y(...)     : used for mangling of external names (see below)
   FFTW(...)  : used for mangling of FFTW API names

NAME MANGLING: use Y(foo) for external names instead of nfft_foo.
    Y(foo) expands to nfftf_foo, nfftl_foo, or nfft_foo, depending
    on the precision.
    
    X(foo) also expands to the corresponding prefix, but is local 
    to each module. I.e. X(foo) will expand to nfct_foo in the 
    NFCT module, but Y(foo) will always be nfft_foo.
    
    FFTW(foo) expands to fftw_foo.
    
    Names that are not exported do not need to be mangled.