Surface fitting for a matrix

Hi,

Do you know how can I obtain surface fit (polynomial) for a matrix of size 20x20. I notice that in the curve fitting toolbox you need to enter your data as X and Y; however I'm not how to use it with a matrix of that size.

I also used imagesc to visualize my values however im not sure if I can do something with the image.

Answer 1

[Ameer Hamza]

If you just have the matrix, then you can use the row and column number as the x and y variables. Try this example

M = ((1:10)+(1:10).').^2;

[X, Y] = meshgrid(1:size(M,2), 1:size(M,1));
fit_model = fit([X(:) Y(:)], M(:), 'poly43');
plot(fit_model, [X(:) Y(:)], M(:))

[Keyla Gonzalez]

Thank you Ameer, it worked perfectly.

[Ameer Hamza]

I am glad to be of help.