Returns

polyfit array: contains information for fitting to arbitrary points using the recursion relations

Examples

fit a 3rd order polynomial to the data in !g.s[0]

    yy = *(!g.s[0].data_ptr)
    xx = dindgen(n_elements(yy))
    f = ortho_fit(xx, yy, 3, cfit, rms)
 

Version

$Id$

Parameters
xx in, required	The x-values to use in the fit.
yy in, required	The data to be fit at xx.
nfit in, required integer	The order of the polynomial to fit.
cfit out, required variable	On return, cfit has coefficients of the polynomial fit = sum(m) a_m x^m because of round-off using this form gives unreliable results above about order 15 even for double precision. See ortho_poly for a better discussion on the contents of cfit.
rms out, required variable	The rms error for each polynomial up to order nfit.