diff options
author | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
---|---|---|
committer | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
commit | 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 (patch) | |
tree | 4464880c571602d54f6ae114729bf62a89518057 /math/bevington/man/curfit.3m | |
download | iraf-osx-40e5a5811c6ffce9b0974e93cdd927cbcf60c157.tar.gz |
Repatch (from linux) of OSX IRAF
Diffstat (limited to 'math/bevington/man/curfit.3m')
-rw-r--r-- | math/bevington/man/curfit.3m | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/math/bevington/man/curfit.3m b/math/bevington/man/curfit.3m new file mode 100644 index 00000000..799f0545 --- /dev/null +++ b/math/bevington/man/curfit.3m @@ -0,0 +1,49 @@ +.TH CURFIT 3M +.SH NAME +curfit +.SH DESCRIPTION +subroutine curfit.f + +source + Bevington, pages 237-239. + +purpose + make least-squares fit to a non-linear function + with a linearization of the fitting function + +usage + call curfit (x, y, sigmay, npts, nterms, mode, a, deltaa, + sigmaa, flamda, yfit, 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 parameters + 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 parameters + deltaa - array of increments for parameters a + sigmaa - array of standard deviations for parameters a + flamda - proportion of gradient search included + yfit - array of calculated values of y + chisqr - reduced chi square for fit + +subroutines and function subprograms required + functn (x, i, a) + evaluates the fitting function for the ith term + fchisq (y, sigmay, npts, nfree, mode, yfit) + evaluates reduced chi squared for fit to data + fderiv (x, i, a, deltaa, nterms, deriv) + evaluates the derivatives of the fitting function + for the ith term with respect to each parameter + matinv (array, nterms, det) + inverts symmetric two-dimension matrix of degree nterms + and calculates its determinant + +comments + valid for nterms up to 10 + set flamda = 0.001 at beginning of search |