claqr1.f(3)							      LAPACK							       claqr1.f(3)

NAME

       claqr1.f -

SYNOPSIS

   Functions/Subroutines
       subroutine claqr1 (N, H, LDH, S1, S2, V)
	   CLAQR1 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 claqr1 (integerN, complex, dimension( ldh, * )H, integerLDH, complexS1, complexS2, complex, dimension( * )V)
       CLAQR1 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, CLAQR1 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 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

	   S2

		     S2 is COMPLEX

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

	   V

		     V is COMPLEX 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 claqr1.f.

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

Version 3.4.2							  Tue Sep 25 2012						       claqr1.f(3)