Linear Fitting starting from a value
2 views (last 30 days)
Show older comments
I need to fit these data [100 90 80 70 50 45 40 43 42 40 35] whom are distanced by 10 seconds.
The problem is that I would fit these data starting from the first value (100) in order to understand the slope of the line.
Is it possible?
Torsten on 10 Oct 2022
Edited: Torsten on 10 Oct 2022
l(x) = a*x + 100
as model function and fit the parameter a.
xdata = ...; % your xdata as column vector
ydata = ...; % your ydata as column vector
a = xdata\(ydata-100)
But starting from a certain x-value, the slope seems to change. You should separate the fit into two parts:
l1(x) = a*x + 100 0 <= x<= x1
l2(x) = b*x + [(a-b)*x1 + 100] x1 <= x <= x(end)
More Answers (1)
Hiro Yoshino on 10 Oct 2022
Edited: Hiro Yoshino on 10 Oct 2022
refline is the easiest way to achieve that.
y = [100 90 80 70 50 45 40 43 42 40 35];
x = 0:10:10*(length(y)-1);
if you want to know the coefficients:
p = polyfit(x,y,1)
polyfit for reference.
Find more on Get Started with Curve Fitting Toolbox in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!Start Hunting!