sign returns a vector with the signs of the corresponding elements of
x (the sign of a real number is 1, 0, or -1 if the number is positive, zero,
or negative, respectively).## S3 method for class 'generic_spct':
sign(x)MathFun,
^.generic_spct,
convolve_each,
div-.generic_spct, log,
minus-.generic_spct,
mod-.generic_spct,
plus-.generic_spct, round,
slash-.generic_spct,
times-.generic_spct