la_lapack::laqr1 Interface Reference

Given a 2-by-2 or 3-by-3 matrix H, LAQR1: sets v to a scalar multiple of the first column of the product (*) K = (H - s1*I)*(H - s2*I) scaling to avoid overflows and most underflows. This is useful for starting double implicit shift bulges in the QR algorithm. More...

Public Member Functions
pure subroutine	claqr1 (n, h, ldh, s1, s2, v)
	la_claqr1
pure subroutine	dlaqr1 (n, h, ldh, sr1, si1, sr2, si2, v)
	la_dlaqr1
	la_qlaqr1
pure subroutine	slaqr1 (n, h, ldh, sr1, si1, sr2, si2, v)
	la_slaqr1
	la_wlaqr1
pure subroutine	zlaqr1 (n, h, ldh, s1, s2, v)
	la_zlaqr1

Detailed Description

Given a 2-by-2 or 3-by-3 matrix H, LAQR1: sets v to a scalar multiple of the first column of the product (*) K = (H - s1*I)*(H - s2*I) scaling to avoid overflows and most underflows. This is useful for starting double implicit shift bulges in the QR algorithm.

Member Function/Subroutine Documentation

claqr1()

pure subroutine la_lapack::laqr1::claqr1	(	integer(ilp), intent(in)	n,
		complex(sp), dimension(ldh,*), intent(in)	h,
		integer(ilp), intent(in)	ldh,
		complex(sp), intent(in)	s1,
		complex(sp), intent(in)	s2,
		complex(sp), dimension(*), intent(out)	v
	)

dlaqr1()

pure subroutine la_lapack::laqr1::dlaqr1	(	integer(ilp), intent(in)	n,
		real(dp), dimension(ldh,*), intent(in)	h,
		integer(ilp), intent(in)	ldh,
		real(dp), intent(in)	sr1,
		real(dp), intent(in)	si1,
		real(dp), intent(in)	sr2,
		real(dp), intent(in)	si2,
		real(dp), dimension(*), intent(out)	v
	)

la_claqr1()

la_lapack::laqr1::la_claqr1

la_dlaqr1()

la_lapack::laqr1::la_dlaqr1

la_qlaqr1()

la_lapack::laqr1::la_qlaqr1

la_slaqr1()

la_lapack::laqr1::la_slaqr1

la_wlaqr1()

la_lapack::laqr1::la_wlaqr1

la_zlaqr1()

la_lapack::laqr1::la_zlaqr1

slaqr1()

pure subroutine la_lapack::laqr1::slaqr1	(	integer(ilp), intent(in)	n,
		real(sp), dimension(ldh,*), intent(in)	h,
		integer(ilp), intent(in)	ldh,
		real(sp), intent(in)	sr1,
		real(sp), intent(in)	si1,
		real(sp), intent(in)	sr2,
		real(sp), intent(in)	si2,
		real(sp), dimension(*), intent(out)	v
	)

zlaqr1()

pure subroutine la_lapack::laqr1::zlaqr1	(	integer(ilp), intent(in)	n,
		complex(dp), dimension(ldh,*), intent(in)	h,
		integer(ilp), intent(in)	ldh,
		complex(dp), intent(in)	s1,
		complex(dp), intent(in)	s2,
		complex(dp), dimension(*), intent(out)	v
	)

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

• la_lapack.f90