Compute the singular-value decomposition of a matrix Eigen
. Both methods are iterative.
The result consists of two orthonormal matrices,
SVD(X, method = c("Jacobi", "eigen"), tol = sqrt(.Machine$double.eps),
max.iter = 100)
a square symmetric matrix
either "Jacobi"
(the default) or "eigen"
zero and convergence tolerance
maximum number of iterations
a list of three elements: d
-- singular values, U
-- left singular vectors, V
-- right singular vectors
The default method is more numerically stable, but the eigenstructure method is much simpler. Singular values of zero are not retained in the solution.
svd
, the standard svd function
# NOT RUN {
C <- matrix(c(1,2,3,2,5,6,3,6,10), 3, 3) # nonsingular, symmetric
C
SVD(C)
# least squares by the SVD
data("workers")
X <- cbind(1, as.matrix(workers[, c("Experience", "Skill")]))
head(X)
y <- workers$Income
head(y)
(svd <- SVD(X))
VdU <- svd$V %*% diag(1/svd$d) %*%t(svd$U)
(b <- VdU %*% y)
coef(lm(Income ~ Experience + Skill, data=workers))
# }
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