integrate

Integrate cfit object

Syntax

int = integrate(fun,x,x0)

Description

int = integrate(fun,x,x0) integrates the cfit object fun at the points specified by the vector x, starting from x0, and returns the result in int. int is a vector the same size as x. x0 is a scalar.

Examples

Create a baseline sinusoidal signal:

xdata = (0:.1:2*pi)';
y0 = sin(xdata);

Add noise to the signal:

noise = 2*y0.*randn(size(y0)); % Response-dependent 
                               % Gaussian noise
ydata = y0 + noise;

Fit the noisy data with a custom sinusoidal model:

f = fittype('a*sin(b*x)');
fit1 = fit(xdata,ydata,f,'StartPoint',[1 1]);

Find the integral of the fit at the predictors:

int = integrate(fit1,xdata,0);

Plot the data, the fit, and the integral:

subplot(2,1,1)
plot(fit1,xdata,ydata) % cfit plot method
subplot(2,1,2)
plot(xdata,int,'m') % double plot method
grid on
legend('integral')

Note that integrals can also be computed and plotted directly with the cfit plot method, as follows:

plot(fit1,xdata,ydata,{'fit','integral'})

The plot method, however, does not return data on the integral.

See Also

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