Really? I think I must be missing something. When I plot them in excel I get the attached results...
On 8 August 2012 13:23, Gilles Sadowski <[email protected]> wrote: > On Tue, Aug 07, 2012 at 11:59:09PM +0100, Mat Jaggard wrote: >> I have tried to create a polynomial that fits some data using the >> following code: >> >> PolynomialFitter fitter = new PolynomialFitter(14, new >> GaussNewtonOptimizer()); >> for (int i = 0; i < numValues; i++) >> { >> fitter.addObservedPoint(xValues[i], yValues[i]); >> } >> return new PolynomialFunction(fitter.fit()); >> >> I've also tried using a degree of 4. In both cases and using both a >> GaussNewtonOptimizer and a LevenbergMarquardtOptimizer, I'm able to >> get a straight line to be fitted correctly, but the following data >> results with a constant value but very small multipliers for x, and >> higher orders. >> >> Is anyone able to let me know why this is happening and what I can do about >> it? >> >> Many thanks, >> Mat. >> >> The result I get is... >> y = 110.281064 + 0.002316943x - 3.86E-09x^2 + 4.01E-15x^3 - 1.58E-21x^4 >> >> From this data: >> >> [...] > > Plotting those data, and the above polynomial shows that Commons Math did a > decent job. What led you to think that the fit is not correct? > [Maybe the data could be better fitted with another function...] > > > Regards, > Gilles > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] >
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