Struggling to get the coefvals for a 2D Poly curve to accurately reproduce the curve as expected
Code example as follows:
clear; clc;%% some input Data
id_cont = 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= 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= linspace(-800,0,8000);%% calc
iq_long = fittingcurve(id_cont, iq_cont,id_long);figure;hold on;plot(id_cont,iq_cont, '+')plot(id_long,iq_long,'*')legend('orig data','fitted curve')%% 2-D Curve fitting
function output_fit = fittingcurve(x_values, y_values, x_data)[xData, yData] = prepareCurveData( x_values, y_values);% Set up fittype and options.
ft = fittype( 'poly9' );% Fit model to data.
[fitresult, gof] = fit( xData, yData, ft, 'Normalize', 'on' );y_coeffvals = coeffvalues(fitresult);x_mean = mean(x_data(1,:));x_std = std(x_data(1,:));output_fit = y_coeffvals(1).*((x_data-x_mean)./x_std).^9 ... + y_coeffvals(2).*((x_data-x_mean)./x_std).^8 ... + y_coeffvals(3).*((x_data-x_mean)./x_std).^7 ... + y_coeffvals(4).*((x_data-x_mean)./x_std).^6 ... + y_coeffvals(5).*((x_data-x_mean)./x_std).^5 ... + y_coeffvals(6).*((x_data-x_mean)./x_std).^4 ... + y_coeffvals(7).*((x_data-x_mean)./x_std).^3 ... + y_coeffvals(8).*((x_data-x_mean)./x_std).^2 ... + y_coeffvals(9).*((x_data-x_mean)./x_std) ... + y_coeffvals(10);endProduces the following plot
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