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author | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
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committer | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
commit | 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 (patch) | |
tree | 4464880c571602d54f6ae114729bf62a89518057 /math/nlfit/doc/nlerrors.hlp | |
download | iraf-osx-40e5a5811c6ffce9b0974e93cdd927cbcf60c157.tar.gz |
Repatch (from linux) of OSX IRAF
Diffstat (limited to 'math/nlfit/doc/nlerrors.hlp')
-rw-r--r-- | math/nlfit/doc/nlerrors.hlp | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/math/nlfit/doc/nlerrors.hlp b/math/nlfit/doc/nlerrors.hlp new file mode 100644 index 00000000..3b463c14 --- /dev/null +++ b/math/nlfit/doc/nlerrors.hlp @@ -0,0 +1,67 @@ +.help nlerrors Feb91 "Nlfit Package" +.ih +NAME +nlerrors -- compute the fit statistics and errors in the parameters +.ih +SYNOPSIS +nlerrors[rd] (nl, z, zfit, w, npts, variance, chisqr, errors) + +.nf +pointer nl # curve descriptor +real/double z[npts] # array of input function values +real/double zfit[npts] # array of fitted function values +real/double w[npts] # array of weights +int npts # number of data points +real/double variance # the computed variance of the fit +real/double chisqr # the computed reduced chi-square of the fit +real/double errors[*] # errors in the fitted parameters +.fi +.ih +ARGUMENTS +.ls nl +Pointer to the curve descriptor structure. +.le +.ls z +Array of function values. +.le +.ls zfit +Array of fitted function values. +.le +.ls w +Array of weights. +.le +.ls npts +The number of data points. +.le +.ls variance +The computed variance of the fit. +.le +.ls chisqr +The computed reduced chi-squared of the fit. +.le +.ls errors +Array of errors in the computed parameters. +.le +.ih +DESCRIPTION +Compute the variance and reduced chi-squared of the fit and the +errors in the fitted parameters. +.ih +NOTES +The reduced chi-squared of the fit is the square root of the sum of the +weighted squares of the residuals divided by the number of degrees of freedom. +The variance of the fit is the square root of the sum of the +squares of the residuals divided by the number of degrees of freedom. +If the weighting is uniform, then the reduced chi-squared is equal to the +variance of the fit. +The error of the j-th parameter is the square root of the j-th diagonal +element of the inverse of the data matrix. If the weighting is uniform, +then the errors are scaled by the square root of the variance of the data. + +The zfit array can be computed by a call to the nlvector[rd] routine. +The size of the array required to hold the output error array can be +determined by a call to nlstati. +.ih +SEE ALSO +nlvector,nlstat +.endhelp |