This subroutine computes the square root of the I-th updated eigenvalue of a positive symmetric rank-one modification to a positive diagonal matrix whose entries are given as the squares of the corresponding entries in the array d, and that 0 <= D(i) < D(j) for i < j and that RHO > 0. This is arranged by the calling routine, and is no loss in generality. The rank-one modified system is thus diag( D ) * diag( D ) + RHO * Z * Z_transpose. where we assume the Euclidean norm of Z is 1. The method consists of approximating the rational functions in the secular equation by simpler interpolating rational functions. More...

Public Member Functions
pure subroutine	dlasd4 (n, i, d, z, delta, rho, sigma, work, info)

	la_dlasd4

	la_qlasd4

pure subroutine	slasd4 (n, i, d, z, delta, rho, sigma, work, info)

	la_slasd4

Detailed Description

This subroutine computes the square root of the I-th updated eigenvalue of a positive symmetric rank-one modification to a positive diagonal matrix whose entries are given as the squares of the corresponding entries in the array d, and that 0 <= D(i) < D(j) for i < j and that RHO > 0. This is arranged by the calling routine, and is no loss in generality. The rank-one modified system is thus diag( D ) * diag( D ) + RHO * Z * Z_transpose. where we assume the Euclidean norm of Z is 1. The method consists of approximating the rational functions in the secular equation by simpler interpolating rational functions.

Member Function/Subroutine Documentation

◆ dlasd4()

pure subroutine la_lapack::lasd4::dlasd4	(	integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	i,
		real(dp), dimension(*), intent(in)	d,
		real(dp), dimension(*), intent(in)	z,
		real(dp), dimension(*), intent(out)	delta,
		real(dp), intent(in)	rho,
		real(dp), intent(out)	sigma,
		real(dp), dimension(*), intent(out)	work,
		integer(ilp), intent(out)	info
	)

◆ la_dlasd4()

la_lapack::lasd4::la_dlasd4

◆ la_qlasd4()

la_lapack::lasd4::la_qlasd4

◆ la_slasd4()

la_lapack::lasd4::la_slasd4

◆ slasd4()

pure subroutine la_lapack::lasd4::slasd4	(	integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	i,
		real(sp), dimension(*), intent(in)	d,
		real(sp), dimension(*), intent(in)	z,
		real(sp), dimension(*), intent(out)	delta,
		real(sp), intent(in)	rho,
		real(sp), intent(out)	sigma,
		real(sp), dimension(*), intent(out)	work,
		integer(ilp), intent(out)	info
	)

The documentation for this interface was generated from the following file:

la_lapack.f90