What is the math function in this example?

[xiaojieguo]

Hi, I want to use LM algorithm in my application.
Could you show me the function in
LMTest.cpp ?

[daviddoria]

I'm not sure what you mean - the function f() is defined as:
fx(0) = pow(x(0) - 2, 2) + pow(x(1) - 4, 2);

which is f(x) = (x(0)-2)^2 + (x(1) - 4)^2

[xiaojieguo]

Thanks. I made a mistake .
But I have another question.
What does the second parameter mean in
vnl_least_squares_function (unsigned int number_of_unknowns, unsigned int number_of_residuals, UseGradient g=use_gradient) ?
Here number_of_residuals >= number_of_unknowns, is it right？
I am confused about number_of_residuals.

[daviddoria]

Sorry, you'll have to ask the VNL folks about this.