polyfitter.multifit

Fit several sets of data to polynomials

Synopsis
multifit(coeff, coefferrs, chisq, x, y, sigma, order)

Arguments

coeff	The coefficients of the fit. The constant (0th-order) term is first, highest order term last. coeff[,1] are the coefficients for the first fit, coeff[,2] for the second, and so on. (Output)
coefferrs	Estimated errors of the fit. coefferrs[,i] are the errors for the ith fit. (Output)
chisq	$\chi^{2}_{}$ for the fit. chisq[i] is the chi-square for the i'th fit. (Output)
x	One dimensional array. (Input)
y	Must be the same length as ``x'' in its first axis, the length of the second axis is the number of fits to do. (Input)
sigma	Errors in the ``y'' values. If one dimensional, the sigmas are assumed to be the same for all fits. (Input)
	Default:	1.0
order	Order of the highest term in the polynomial to fit. (Input)
	Allowed:	0 $\le$ order $\le$ 10
	Default:	1

Returns
Bool -- did the fit succeed

Description
Fits a polynomial to multiple data sets (which must share the same x however)^1.2. Basically, this is the same as fit (without an error message - errors are in the log messages), except the dimensionality of all arguments is one higher. This function runs in C++ at the same speed as fit, however it minimizes the communication over the Glish bus, which would limit you to 100 fits or less per second.

Example

  include "polyfitter.g"
T 
  x := 1:100
  y := array(0, 100, 3)
  y[,1] := 5                    # constant
  y[,2] := 2*x                  # linear       
  y[,3] := 10*x*x               # square    
  fitter := polyfitter()
  fitter.multifit(coeff, coefferrs, chisq, x, y, order=2) 
1 
  coeff[,1]                     # the first fit
[5 -2.98023e-08 0]  
  coeff[,2]                     # the second fit
[0.00126371 2 3.93629e-08]  
  coeff[,3]                     # the third fit
[0.00238887 -0.000247818 10]

Next: polyfitter.eval - Function Up: polyfitter - Tool Previous: polyfitter.fit - Function Contents Index

	Package	utility
	Module	mathematics
	Tool	polyfitter

polyfitter.multifit - Function