How to Resolve Vector Size Mismatch Error in MATLAB Convolution Fitting?

[Niles]

Hi

I have the following piece of code:

dataX = -4:1:4;
dataY = [0 -1 -10 -40 -55 10 40 10 1];

figure(1)
plot(dataX, dataY, '*');

x = -2:0.01:2;
plot(-4:0.01:4, 1*conv(exp(-x).*heaviside(x),sin(x)), dataX, dataY, '*')

mdl = @(a, x)(a(1)*conv(exp(-x).*heaviside(x),sin(x)));

par=[1];
[fitted_par, r, J, cov, mse] = nlinfit(dataX, dataY, mdl, par);

What I am trying to do is to fit the function (a convolution) to the data set. However, I get an error due to vector size mismatch. I'm not sure what is going on here: The fitting routine should not care about how many data points I have?

Regards, Niels.

 

[mmwave]

Hello Niels,

Thank you for sharing your code. It seems like the issue you are encountering is due to the size of your dataX and dataY vectors not matching the size of the x vector in your mdl function. The fitting routine does not care about the number of data points, but it does require that the input vectors have the same size.

In order to fix this, you can either adjust the size of your dataX and dataY vectors to match the size of x, or you can modify your mdl function to accept variable sizes for the input vectors. For example, you can use the "min" function to ensure that the input vectors are the same size before performing the convolution.

I hope this helps. Let me know if you have any further questions. Happy coding!