POLFIT(3M)

NAME
polfit

DESCRIPTION
subroutine polfit.f source
  Bevington, pages 140-142. purpose
  make least-squares fit to data with a polynomial curve
    y = a(1) + a(2)*x + a(3)*x**2 + a(3)*x**3 + . . . usage
  call polfit (x, y, sigmay, npts, nterms, mode, a, chisqr) description of parameters
  x - array of data points for independent variable
  y - array of data points for dependent variable
  sigmay - array of standard deviations for y data points
  npts - number of pairs of data points
  nterms - number of coefficients (degree of polynomial + 1)
  mode - determines method of weighting least-squares fit
           +1 (instrumental) weight(i) = 1./sigmay(i)**2
            0 (no weighting) weight(i) = 1.
           -1 (statistical) weight(i) = 1./y(i)
  a - array of coefficients of polynomial
  chisqr - reduced chi square for fit subroutines and function subprograms required
  determ (array, norder)
    evaluates the determinant of a symetrical
      two-dimension matrix of order norder comments
  valid for nterms up to 10