Lsqcurvefit for 2 parameters

I read over the lsqcurvefit for one parameter.

x=lsqcurvefit(fun,xo,xdata,ydata)

where xo= initial x,

fun is the function to calculate xdata at xo.

I have 2 parameters needs to adjust to get xdata

let say xo,yo are two initial conditions. fun is the function to calculate xdata at xo,yo

How do I use lsqcurvefit to find the right x,y values.

For example:

xdata=[ 1 2]; ydata=[0.9 1.5];

Initial guess xo=1, yo=10^-4

fun: is the function which I dont know the specific form and that is my code to calculate xdata based on xo,yo.

Now I want to find the correct xo,yo.

I could not access the link that you gave.

[Sean de Wolski]

Can you provide an actual example of what you have?

The documentation gives some examples of using lsqcurvefit.

http://www.mathworks.com/help/releases/R2013b/optim/ug/lsqcurvefit.html

Answer 1

[Matt J]

I read over the lsqcurvefit for one parameter. x=lsqcurvefit(fun,x0,xdata,ydata)

No, this is not a 1-parameter syntax. x and x0 are vectors. If you pass a 2x1 initial vector x0 as input, then lsqcurvefit will know that fun(x,xdata) is a function of a 2x1 parameter vector x.

[Laura]

You meant that if I give xo=[ 1 10^-4]. It will give me 2 parameters for x which is x and y?

[Matt J]

Yes. But you must write your fun(x,xdata) so that it expects x to be 1x2 vector argument as well.