la_lapack::stegr Interface Reference

STEGR: computes selected eigenvalues and, optionally, eigenvectors of a real symmetric tridiagonal matrix T. Any such unreduced matrix has a well defined set of pairwise different real eigenvalues, the corresponding real eigenvectors are pairwise orthogonal. The spectrum may be computed either completely or partially by specifying either an interval (VL,VU] or a range of indices IL:IU for the desired eigenvalues. STEGR is a compatibility wrapper around the improved CSTEMR routine. See SSTEMR for further details. One important change is that the ABSTOL parameter no longer provides any benefit and hence is no longer used. Note : STEGR and CSTEMR work only on machines which follow IEEE-754 floating-point standard in their handling of infinities and NaNs. Normal execution may create these exceptiona values and hence may abort due to a floating point exception in environments which do not conform to the IEEE-754 standard. More...

Public Member Functions
pure subroutine	cstegr (jobz, range, n, d, e, vl, vu, il, iu, abstol, m, w, z, ldz, isuppz, work, lwork, iwork, liwork, info)
	la_cstegr
pure subroutine	dstegr (jobz, range, n, d, e, vl, vu, il, iu, abstol, m, w, z, ldz, isuppz, work, lwork, iwork, liwork, info)
	la_dstegr
	la_qstegr
pure subroutine	sstegr (jobz, range, n, d, e, vl, vu, il, iu, abstol, m, w, z, ldz, isuppz, work, lwork, iwork, liwork, info)
	la_sstegr
	la_wstegr
pure subroutine	zstegr (jobz, range, n, d, e, vl, vu, il, iu, abstol, m, w, z, ldz, isuppz, work, lwork, iwork, liwork, info)
	la_zstegr

Detailed Description

STEGR: computes selected eigenvalues and, optionally, eigenvectors of a real symmetric tridiagonal matrix T. Any such unreduced matrix has a well defined set of pairwise different real eigenvalues, the corresponding real eigenvectors are pairwise orthogonal. The spectrum may be computed either completely or partially by specifying either an interval (VL,VU] or a range of indices IL:IU for the desired eigenvalues. STEGR is a compatibility wrapper around the improved CSTEMR routine. See SSTEMR for further details. One important change is that the ABSTOL parameter no longer provides any benefit and hence is no longer used. Note : STEGR and CSTEMR work only on machines which follow IEEE-754 floating-point standard in their handling of infinities and NaNs. Normal execution may create these exceptiona values and hence may abort due to a floating point exception in environments which do not conform to the IEEE-754 standard.

Member Function/Subroutine Documentation

cstegr()

pure subroutine la_lapack::stegr::cstegr	(	character, intent(in)	jobz,
		character, intent(in)	range,
		integer(ilp), intent(in)	n,
		real(sp), dimension(*), intent(inout)	d,
		real(sp), dimension(*), intent(inout)	e,
		real(sp), intent(in)	vl,
		real(sp), intent(in)	vu,
		integer(ilp), intent(in)	il,
		integer(ilp), intent(in)	iu,
		real(sp), intent(in)	abstol,
		integer(ilp), intent(out)	m,
		real(sp), dimension(*), intent(out)	w,
		complex(sp), dimension(ldz,*), intent(out)	z,
		integer(ilp), intent(in)	ldz,
		integer(ilp), dimension(*), intent(out)	isuppz,
		real(sp), dimension(*), intent(out)	work,
		integer(ilp), intent(in)	lwork,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(in)	liwork,
		integer(ilp), intent(out)	info
	)

dstegr()

pure subroutine la_lapack::stegr::dstegr	(	character, intent(in)	jobz,
		character, intent(in)	range,
		integer(ilp), intent(in)	n,
		real(dp), dimension(*), intent(inout)	d,
		real(dp), dimension(*), intent(inout)	e,
		real(dp), intent(in)	vl,
		real(dp), intent(in)	vu,
		integer(ilp), intent(in)	il,
		integer(ilp), intent(in)	iu,
		real(dp), intent(in)	abstol,
		integer(ilp), intent(out)	m,
		real(dp), dimension(*), intent(out)	w,
		real(dp), dimension(ldz,*), intent(out)	z,
		integer(ilp), intent(in)	ldz,
		integer(ilp), dimension(*), intent(out)	isuppz,
		real(dp), dimension(*), intent(out)	work,
		integer(ilp), intent(in)	lwork,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(in)	liwork,
		integer(ilp), intent(out)	info
	)

la_cstegr()

la_lapack::stegr::la_cstegr

la_dstegr()

la_lapack::stegr::la_dstegr

la_qstegr()

la_lapack::stegr::la_qstegr

la_sstegr()

la_lapack::stegr::la_sstegr

la_wstegr()

la_lapack::stegr::la_wstegr

la_zstegr()

la_lapack::stegr::la_zstegr

sstegr()

pure subroutine la_lapack::stegr::sstegr	(	character, intent(in)	jobz,
		character, intent(in)	range,
		integer(ilp), intent(in)	n,
		real(sp), dimension(*), intent(inout)	d,
		real(sp), dimension(*), intent(inout)	e,
		real(sp), intent(in)	vl,
		real(sp), intent(in)	vu,
		integer(ilp), intent(in)	il,
		integer(ilp), intent(in)	iu,
		real(sp), intent(in)	abstol,
		integer(ilp), intent(out)	m,
		real(sp), dimension(*), intent(out)	w,
		real(sp), dimension(ldz,*), intent(out)	z,
		integer(ilp), intent(in)	ldz,
		integer(ilp), dimension(*), intent(out)	isuppz,
		real(sp), dimension(*), intent(out)	work,
		integer(ilp), intent(in)	lwork,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(in)	liwork,
		integer(ilp), intent(out)	info
	)

zstegr()

pure subroutine la_lapack::stegr::zstegr	(	character, intent(in)	jobz,
		character, intent(in)	range,
		integer(ilp), intent(in)	n,
		real(dp), dimension(*), intent(inout)	d,
		real(dp), dimension(*), intent(inout)	e,
		real(dp), intent(in)	vl,
		real(dp), intent(in)	vu,
		integer(ilp), intent(in)	il,
		integer(ilp), intent(in)	iu,
		real(dp), intent(in)	abstol,
		integer(ilp), intent(out)	m,
		real(dp), dimension(*), intent(out)	w,
		complex(dp), dimension(ldz,*), intent(out)	z,
		integer(ilp), intent(in)	ldz,
		integer(ilp), dimension(*), intent(out)	isuppz,
		real(dp), dimension(*), intent(out)	work,
		integer(ilp), intent(in)	lwork,
		integer(ilp), dimension(*), intent(out)	iwork,
		integer(ilp), intent(in)	liwork,
		integer(ilp), intent(out)	info
	)

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

• la_lapack.f90