confusing error message: 'Not enough input arguments'?

Having:

function [f] = Simple(x)
f = (x(1)-1).^2  + (x(2)-1).^2;
end

and running:

x = lsqnonlin(Simple, [2.0, 2.0])

I am getting:

Not enough input arguments.

Error in Simple (line 2)

f = (x(1)-1).^2 + (x(2)-1).^2;

2 f = (x(1)-1).^2 + (x(2)-1).^2;

What is going on here?

[Valeri Aronov]

Thanks, Star. It was helpful, inlike Matlab's error message ;-(

[Star Strider]

As always, my pleasure!

Answer 1

[Star Strider]

With a function in that format, it is necessary to pass a function handle to lsqnonlin (or any other function that takes a function handle argument):

x = lsqnonlin(@Simple, [2.0, 2.0])

That is not the situation for anonymous functions that are already function handle objects:

Simple = @(x) (x(1)-1).^2  + (x(2)-1).^2;

x = lsqnonlin(Simple, [2.0, 2.0])

producing:

x =
   1.000244655961070   1.000244655961070

See What Is a Function Handle? for details.

.