How do I perform a linear least squares fit

1,395 ビュー (過去 30 日間)
Alexander MacFarlane IV
Alexander MacFarlane IV 2018 年 12 月 21 日
編集済み: Tamas Kis 2021 年 7 月 26 日
Hello.
I would like to perform a linear least squares fit to 3 data points.
The help files are very confusing, to the point where i can't figure out whether this is a base function of Matlab, I need the curve fitting toolbox, optimization toolbox, or both.
Thanks,
Alex

採用された回答

Star Strider
Star Strider 2018 年 12 月 21 日
You don’t need any toolboxes. Use polyfit (link) and polyval functions, or the mldivide (link) operator.

その他の回答 (2 件)

Image Analyst
Image Analyst 2018 年 12 月 21 日
編集済み: Image Analyst 2018 年 12 月 21 日
See attached polyfit demo. Adapt as needed. All you need is base MATLAB - no toolboxes.
For example
coefficients = polyfit(x, y, 1);
yFitted = polyval(coefficients, x); % yFitted will be at the 3 points where x is. There will be 3 yFitted values.
If you want a lot more points, you can pass in more x to polyval():
xFit = linspace(min(x), max(x), 1000); % 1000 points.
yFitted = polyval(coefficients, xFit);
  1 件のコメント
Alexander MacFarlane IV
Alexander MacFarlane IV 2018 年 12 月 21 日
Thanks Star Strider and Image Analyst!
You guys are amazingly fast.

サインインしてコメントする。


Tamas Kis
Tamas Kis 2021 年 7 月 25 日
編集済み: Tamas Kis 2021 年 7 月 26 日
Function to perform curve fitting using linear least squares:
Linear and polynomial fits are linear least square fits, while the other fits (power, exponential, logarithmic) are approximated by first linearizing the data.

タグ

製品


リリース

R2018b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by