Isolate the linear segment of data/graph
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I am trying to create a script where I plot data and I need to find the slope of the most linear segment of the data/graph. Any ideas on how I can do that for a script whose data will vary for each trial.
3 个评论
Are you refering to the vertical line at x=0?
Define "most linear". What segment is most linear in this plot below?
plot(round(sin(-4:.05:4)))
axis padded
Luis Martin Romero
2021-8-30
Adam Danz
2021-8-30
I'd compute the slope using gradient as Star Strider recommended. If you plot the results you'll see a relatively straight line at some high value and will be precipitously fall off at the point where the original data starts to call off. To quantitatively determine the endpoint of the 'straight' line, you could take the 2nd derivative (gradient of the gradient) to locate the first spike that crosses a threhold you set.
采纳的回答
One reasonably straightforward way to determine the slope of a curve is to use the gradient function.
For example, the gradient of the hyperbolic tangent function:
x = linspace(-4, 4, 500);
f = tanh(x);
dfdx = gradient(f) ./ gradient(x);
figure
plot(x, f)
hold on
plot(x, dfdx)
hold off
grid
legend('Function','Derivative', 'Location','best')
Then use the gradient result to determine what parts of the curve have the characteristics you’re interested in.
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