# PCA file calculation with "R".

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**X**es la matriz centrada (

*).*

**X**is the centered matrix**Xcov**es la matriz de covarianzas de X

*(Xcov is the covariance matrix of X).*

Con la función

**“eigen”**calculamos los “eigenvectors” y “eigenvalues” de Xcov*.(With the function***“eigen”**we calculate the “eigenvectors” and “eigenvalues” of**Xcov**).Para hacer todo al mismo tiempo, podemos usar la función “prcomp”.

*(**To do everything at the same time we can use the function “prcomp”).*La diferencia es que con

**eigen**obtenemos la varianza y con**prcomp**las desviaciones estándar.*The diference is that with*

**eigen**we get the variances, and with**prcomp**the standard deviations.*We can compare this results with the PCA file got in Win ISI in the previous post.*

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