function c = wv_cents(f, fref)
% WV_CENTS  The interval from fref up to f, in cents.
%
% A cent is a hundredth of an equal-tempered semitone, so an octave is 1200
% cents and a relative frequency error e is about 1731 e cents when e is
% small.  Negative means flat.
c = 1200 * log2(f ./ fref);
end