CLAQR1(3f)          LAPACK auxiliary routine (version 3.1)          CLAQR1(3f)



NAME
SYNOPSIS
       SUBROUTINE CLAQR1( N, H, LDH, S1, S2, V )

           COMPLEX        S1, S2

           INTEGER        LDH, N

           COMPLEX        H( LDH, * ), V( * )

           COMPLEX        ZERO

           PARAMETER      ( ZERO = ( 0.0e0, 0.0e0 ) )

           REAL           RZERO

           PARAMETER      ( RZERO = 0.0e0 )

           COMPLEX        CDUM

           REAL           H21S, H31S, S

           INTRINSIC      ABS, AIMAG, REAL

           REAL           CABS1

           CABS1(         CDUM ) = ABS( REAL( CDUM ) ) + ABS( AIMAG( CDUM ) )

           IF(            N.EQ.2 ) THEN

           S              = CABS1( H( 1, 1 )-S2 ) + CABS1( H( 2, 1 ) )

           IF(            S.EQ.RZERO ) THEN

           V(             1 ) = ZERO

           V(             2 ) = ZERO

           ELSE

           H21S           = H( 2, 1 ) / S

           V(             1 ) = H21S*H( 1, 2 ) + ( H( 1, 1 )-S1 )* ( ( H( 1, 1
                          )-S2 ) / S )

           V(             2 ) = H21S*( H( 1, 1 )+H( 2, 2 )-S1-S2 )

           END            IF

           ELSE

           S              = CABS1( H( 1, 1 )-S2 ) + CABS1( H( 2, 1 ) ) +
                          CABS1( H( 3, 1 ) )

           IF(            S.EQ.ZERO ) THEN

           V(             1 ) = ZERO

           V(             2 ) = ZERO

           V(             3 ) = ZERO

           ELSE

           H21S           = H( 2, 1 ) / S

           H31S           = H( 3, 1 ) / S

           V(             1 ) = ( H( 1, 1 )-S1 )*( ( H( 1, 1 )-S2 ) / S ) + H(
                          1, 2 )*H21S + H( 1, 3 )*H31S

           V(             2 ) = H21S*( H( 1, 1 )+H( 2, 2 )-S1-S2 ) + H( 2, 3
                          )*H31S

           V(             3 ) = H31S*( H( 1, 1 )+H( 3, 3 )-S1-S2 ) + H21S*H(
                          3, 2 )

           END            IF

           END            IF

           END

PURPOSE
 LAPACK auxiliary routine (versioNovember 2006                      CLAQR1(3f)
