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What is titanium in the example on fitting a Gaussian model?

In the documentation on fit, the Gaussian model was created by:

[x,y] = titanium;
f = fit(x.',y.','gauss2');
plot(f,x,y)

I was wondering what is titanium? I can't find any relevant explanation to this topic. My questions are what is titanium and what data does it hold?

Solution

  • It's a build-in example for this purpose:

    which titanium
C:\Program Files\MATLAB\R2016b\toolbox\curvefit\splines\titanium.m

[x,y] titanium; % both 1x49 vectors
plot(x,y,'o')

    This is the image of the data:

    enter image description here

    Basically it's an arbitrary example data set for demonstrating the use of e.g. the Gaussian fit. When using the fit function, you'll use your own data for x and y of course, but to get a meaningful example it has been chosen not to use x=rand(1,49), but rather a curve.

    It has its own documentation, thanks to Cris Luengo for pointing that out, which states it is a standard test set first used in the paper C. de Boor and J. R. Rice. "Least squares cubic spline approximation II - Variable knots." CSD TR 21, Comp.Sci., Purdue Univ., April 1968. It depicts some property of titanium as a function of temperature.