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zlaqr1.f(3)				      LAPACK				      zlaqr1.f(3)

NAME
       zlaqr1.f -

SYNOPSIS
   Functions/Subroutines
       subroutine zlaqr1 (N, H, LDH, S1, S2, V)
	   ZLAQR1 sets a scalar multiple of the first column of the product of 2-by-2 or 3-by-3
	   matrix H and specified shifts.

Function/Subroutine Documentation
   subroutine zlaqr1 (integerN, complex*16, dimension( ldh, * )H, integerLDH, complex*16S1,
       complex*16S2, complex*16, dimension( * )V)
       ZLAQR1 sets a scalar multiple of the first column of the product of 2-by-2 or 3-by-3
       matrix H and specified shifts.

       Purpose:

		 Given a 2-by-2 or 3-by-3 matrix H, ZLAQR1 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.

       Parameters:
	   N

		     N is integer
			 Order of the matrix H. N must be either 2 or 3.

	   H

		     H is COMPLEX*16 array of dimension (LDH,N)
			 The 2-by-2 or 3-by-3 matrix H in (*).

	   LDH

		     LDH is integer
			 The leading dimension of H as declared in
			 the calling procedure.  LDH.GE.N

	   S1

		     S1 is COMPLEX*16

	   S2

		     S2 is COMPLEX*16

		     S1 and S2 are the shifts defining K in (*) above.

	   V

		     V is COMPLEX*16 array of dimension N
			 A scalar multiple of the first column of the
			 matrix K in (*).

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   September 2012

       Contributors:
	   Karen Braman and Ralph Byers, Department of Mathematics, University of Kansas, USA

       Definition at line 108 of file zlaqr1.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			      zlaqr1.f(3)
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