LARRK: computes one eigenvalue of a symmetric tridiagonal matrix T to suitable accuracy. This is an auxiliary code to be called from DSTEMR. To avoid overflow, the matrix must be scaled so that its largest element is no greater than overflow**(1/2) * underflow**(1/4) in absolute value, and for greatest accuracy, it should not be much smaller than that. See W. Kahan "Accurate Eigenvalues of a Symmetric Tridiagonal Matrix", Report CS41, Computer Science Dept., Stanford University, July 21, 1966. More...

Public Member Functions
pure subroutine	dlarrk (n, iw, gl, gu, d, e2, pivmin, reltol, w, werr, info)

	la_dlarrk

	la_qlarrk

pure subroutine	slarrk (n, iw, gl, gu, d, e2, pivmin, reltol, w, werr, info)

	la_slarrk

Detailed Description

LARRK: computes one eigenvalue of a symmetric tridiagonal matrix T to suitable accuracy. This is an auxiliary code to be called from DSTEMR. To avoid overflow, the matrix must be scaled so that its largest element is no greater than overflow**(1/2) * underflow**(1/4) in absolute value, and for greatest accuracy, it should not be much smaller than that. See W. Kahan "Accurate Eigenvalues of a Symmetric Tridiagonal Matrix", Report CS41, Computer Science Dept., Stanford University, July 21, 1966.

Member Function/Subroutine Documentation

◆ dlarrk()

pure subroutine la_lapack::larrk::dlarrk	(	integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	iw,
		real(dp), intent(in)	gl,
		real(dp), intent(in)	gu,
		real(dp), dimension(*), intent(in)	d,
		real(dp), dimension(*), intent(in)	e2,
		real(dp), intent(in)	pivmin,
		real(dp), intent(in)	reltol,
		real(dp), intent(out)	w,
		real(dp), intent(out)	werr,
		integer(ilp), intent(out)	info
	)

◆ la_dlarrk()

la_lapack::larrk::la_dlarrk

◆ la_qlarrk()

la_lapack::larrk::la_qlarrk

◆ la_slarrk()

la_lapack::larrk::la_slarrk

◆ slarrk()

pure subroutine la_lapack::larrk::slarrk	(	integer(ilp), intent(in)	n,
		integer(ilp), intent(in)	iw,
		real(sp), intent(in)	gl,
		real(sp), intent(in)	gu,
		real(sp), dimension(*), intent(in)	d,
		real(sp), dimension(*), intent(in)	e2,
		real(sp), intent(in)	pivmin,
		real(sp), intent(in)	reltol,
		real(sp), intent(out)	w,
		real(sp), intent(out)	werr,
		integer(ilp), intent(out)	info
	)

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

la_lapack.f90