- s <- svd(MASS::ginv(crossprod(matricize(X[Z_indice, ])))
- %*% crossprod(matricize(X[Z_indice, ]), matricize(Y[Z_indice, ])))
+ s <- svd(MASS::ginv(crossprod(matricize(X[Z_indice, ]))) %*%
+ crossprod(matricize(X[Z_indice, ]), matricize(Y[Z_indice, ])))