Problem with Gaussian fit to Data

2015 11 6
1 个回答
更新时间：2015 11 6
13 次查看（30 天）

0 个投票

What is wrong with this Gaussian Fit:
gaussEqn = 'a*exp(-((x-b)/c)^2)+d'
f = fit(xdata.',ydata.',gaussEqn)
%Results of fit
coeffs=coeffvalues(f);
a=coeffs(1)
b=coeffs(2)
c=coeffs(3)
d=coeffs(4)
xValue=7;
sp=3;
%Create fine data to plot fit
xdataF=(linspace(xValue-sp,xValue+sp,10*sp))
fitGaus = a*exp(-((xdataF-b)/c)^2)+d
yvalue=ym;
xpeak=xdataF(find(fity==ym));
xpeak=mean(xpeak(:)); %Take mean incase more than one peak found
the fit is fine:
f =
General model:
f(x) = a*exp(-((x-b)/c)^2)+d
Coefficients (with 95% confidence bounds):
a = 0.7094
b = 0.7547
c = 0.276
d = 1482 (-1823, 4787)
But I get the error:
Error using ^
Inputs must be a scalar and a square matrix.
To compute elementwise POWER, use POWER (.^) instead.
Error in HiSeqDistortionTool>fitLocalPeak (line 726)
fitGaus = a*exp(-((xdataF-b)/c)^2)+d

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回答（1 个）

Thorsten
Thorsten 2015-11-6

0 个投票

gaussEqn = 'a*exp(-((x-b)/c).^2)+d'

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Jason
Jason 2015-11-6
编辑：Jason 2015-11-6
OK thanks. I'm still running into problems. This is my x&y data:
ydata =
0 814 2254 4636 3608 1355 65
xdata =
4 5 6 7 8 9 10
I want to do the fit, and then plot at a higher resolution and then find the max y and x value of this in high resolution fit.
%Gaussian Fit--------------------------------------------------------
gaussEqn = 'a*exp(-((x-b)/c).^2)+d'
f = fit(xdata',ydata',gaussEqn)
%Results of fit
coeffs=coeffvalues(f);
a=coeffs(1)
b=coeffs(2)
c=coeffs(3)
d=coeffs(4)
figure
plot(xdata',ydata','r.') %plot raw data
hold on;
plot(f,'r--') %plot fit
%Increase resolution of x data
xdataFine=(linspace(xdata(1),xdata(end),30))
%plot high res fit
fitGaus = a*exp(-((xdataFine-b)/c).^2)+d
plot(fitGaus,'g-')
hold off.
%Find max value and its x location
ym=max(fitGaus);
yvalue=ym;
xpeak=xdataFine(find(fitGaus==ym));
xpeak=mean(xpeak(:)); %Take mean incase more than one peak found

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Jason
Jason
2015-11-6

编辑：

Jason
Jason
2015-11-6

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