Hello, I am really new at matlab. I am trying to create a sub-function that has an input of two vectors and output the RMSE between the values in the vectors. Anyone can help? I would love to understand step by step. thanks to anybody that can help!!

 Réponse acceptée

Star Strider
Star Strider le 5 Mar 2018
Modifié(e) : MathWorks Support Team le 2 Mar 2023

5 votes

UPDATE: Starting in R2022b, you can now calculate Root Mean Square Error using the built in MATLAB function ‘rmse’:
*************************************************************
‘RMSE’ of course means ‘root mean squared error’, or the square root of the mean of the squared error.
The simplest code for this is then:
V1 = rand(10,1);
V2 = rand(10,1);
RMSE = sqrt(mean((V1-V2).^2));
where the error is (V1-V2), and ‘.^2’ denotes element-wise squaring of the error (the difference between ‘V1’ and ‘V2’). The rest of the expression takes the mean of the squared differences, and sqrt takes the square root, completing the definition.
See: Array vs. Matrix Operations (link) and Vectorization (link) for more information.

12 commentaires

silvia battistella
silvia battistella le 6 Mar 2018
thank you so much!!!
Star Strider
Star Strider le 6 Mar 2018
As always, my pleasure!
Abinaya G EMBDD
Abinaya G EMBDD le 21 Août 2019
what is v1 and v2
Star Strider
Star Strider le 21 Août 2019
Anything you want them to be!
MAT-Magic
MAT-Magic le 18 Jan 2020
Modifié(e) : MAT-Magic le 18 Jan 2020
@ Dear Star Strider can we use the below formula for V1 and V2?
difference = single(1) - single(2);
squaredError = difference .^ 2;
meanSquaredError = sum(squaredError(:)) / numel(signal(1));
rmsError = sqrt(meanSquaredError);
Thanks
Star Strider
Star Strider le 18 Jan 2020
That appears to be the correct way to calculate RMSE.
MAT-Magic
MAT-Magic le 18 Jan 2020
Thanks. I edited the question and removed the mistakes.
Star Strider
Star Strider le 18 Jan 2020
My pleasure.
I assume ‘single(1)’ and ‘single(2)’ are actually equal-length vectors.
Image Analyst
Image Analyst le 18 Jan 2020
There is an rms() function that you can use. It's been in the Signal Processing Toolbox since R2012a.
MAT-Magic
MAT-Magic le 19 Jan 2020
@Star Yes, it's right.
@Image Thanks for the reply.
Rachel Hall
Rachel Hall le 24 Avr 2020
@Image Analyst,
I don't think RMSE and RMS are the same; I'm currently fining that out...
Marcos Conde
Marcos Conde le 26 Jan 2022
Yes and No. Actually, RMSE=rms(E), since E(rror) is the difference. In the example above: RMSE=rms(V1-V2)

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Plus de réponses (1)

Rik
Rik le 5 Mar 2018

3 votes

To learn Matlab, you can use a guide like this one.
There are two main ways of doing this: an anonymous function and a 'normal' function.
%anonymous function:
calculate_RMSE=@(a,b) sqrt(mean((a(:)-b(:)).^2));
%normal function (save this in calc_RMSE.m)
function rmse=calc_RMSE(a,b)
rmse=sqrt(mean((a(:)-b(:)).^2));
The two function can be used in the exact same way. The second option provides more options for checking if the input is correct.

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