How can I improve regression results by adjusting the goodness of fit metric?

  • Thread starter Thread starter Khashishi
  • Start date Start date
  • Tags Tags
    Regression Squares
AI Thread Summary
To improve regression results when fitting experimental data with constrained Gaussians, the current approach using sum(chi squared error) may not be optimal due to background signals. A proposed solution is to adopt a different goodness of fit metric that prioritizes fitting a subset of pixels well, rather than achieving a mediocre fit across all pixels. The concept of least trimmed squares is suggested as a potential method to achieve this targeted fitting. This approach focuses on minimizing errors for a specified number of pixels, which aligns with the user's preference for quality over quantity in fitting. Exploring established methods like least trimmed squares could enhance the fitting process without unnecessary reinvention.
Khashishi
Science Advisor
Messages
2,812
Reaction score
490
I'm doing some line fitting on experimental data. Basically I have some array of pixels, and a value measured at each pixel, and I am fitting it with several constrained Gaussians. I'm using a Levenburg-Marquadt nonlinear least squares algorithm called mpfit to fit the parameters, but the results aren't so good due to the existence of background signals in the data.

I'm thinking I could do a better fit using a different "metric" for computing goodness of fit than sum(chi squared error). I want the difference between the model function and the data to be small over many pixels, but not necessarily all of the pixels. That is, I prefer a fit that matches 10 out of 30 pixels very well (but 20 pixels very poorly) over a fit that fits all 30 pixels in a mediocre way. Has anything like this been done before? I don't want to reinvent the wheel.
 
Mathematics news on Phys.org
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Thread 'Imaginary Pythagoras'
I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...

Similar threads

Back
Top