# Explained covariance?

Hi,

This may reflect my lack of understanding of PLS, but the explained_variance attribute gives the percent variance explained by each component for X and for Y. Is there a way to find the percent covariance between X and Y explained by each component?

Thanks.

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hi @user2842,

The easiest way would be to simply calculate the sample covariance(object\$variates\$X[,1], object\$variates\$Y[,1]) for example for component 1,=.

To get the total covariance explained: Rd(X, Y) = Rd(X, object\$variates\$Y), and Rd(Y,X) = Rd(Y, object\$variates\$X) but that assumes you have calculated all possible dimensions. At this stage I can’t really comment on whether this is possible. Let me know if you find a better answer.

Kim-Anh

what function is Rd?

Rd is not a specific function within the `mixOmics` package. The formula in the above excerpt describes a measure (“redundancy”) of the explained variance of a given component.

If you are wanting to examine the source code used to calculate the explained variance, look at the `explained_variance()` function - found here.

Dear all,

I am very interesting in the concept of ‘explained_covariance’, so please let me know if there is any update on that topic!
Moreover, I don’t really understand why ‘explained_variance’ seems quite simple to compute, but not ‘explained_covariance’… Best,
Emile