MATLAB: How to know which plot is more linear then the other

compare the linearity of two plotsCurve Fitting ToolboxImage Processing ToolboxMATLABSignal Processing Toolbox

Dear all,
I have two datasets arrays:
A = [0
0.423891532
0.819380304
1.289479809
1.739548357
2.288748183
2.8990623
3.618974647
4.402757506
5.268816221
6.240886445
7.278958674
8.321358342
9.369407383
10.37825178
11.17417756
12.02774088
12.69808163
13.49653247
14.36958724
15.50198578
16.68295148
20.09421834]
%%


B = [0
0.406558949
0.771247013
1.123943155
1.487752056
1.915016538
2.365427777
2.852526752
3.419995212
3.933726314
4.436914792
4.958793052
5.510476759
5.961517074
6.415268974
6.843890692
7.102927349
7.118216122
7.677116245
8.751585797
9.636923065
10.32502819
12.9488068]
%%
plot(A, 'green')
hold on
plot(B, 'blue')
hold off
%%
Both A and B are nonlinear curves, but B seems to be more linear (less curvature) than A.
How can I show such information numerically?
Any sugguestion will be appreciated.
Best,
Meshoo

Best Answer

  • You can see the residual error with linear fit to see which dataset is more linear
    [~, eA] = polyfit(1:numel(A), A, 1)
    [~, eB] = polyfit(1:numel(B), B, 1)
    Result
    >> eA.normr
    ans =
        4.0713
    >> eB.normr
    ans =
        2.8868
    Vector 'B' is more linear as compared to A.
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