abs(x) computes the absolute value of x, sqrt(x)
computes the (principal) square root of x. The functions are applied
to the spectral data, not the wavelengths. The quantity in the spectrum to
which the function is applied depends on the class of x and the
current value of output options.
# S3 method for generic_spct
sqrt(x)# S3 method for generic_spct
abs(x)
an object of class "generic_spct"