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SUBROUTINE DTREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
$ LDVR, MM, M, WORK, INFO )
DOUBLE PRECISION T( LDT, * ), VL( LDVL, * ), VR( LDVR, * ),
$ WORK( * )
DOUBLE PRECISION X( 2, 2 )
CALL DLALN2( .FALSE., 1, 1, SMIN, ONE, T( J, J ),
$ ZERO, X, 2, SCALE, XNORM, IERR )
CALL DSCAL( KI, SCALE, WORK( 1+N ), 1 )
DO 90 J = KI - 2, 1, -1
IF( J.GT.JNXT )
$ GO TO 90
JNXT = J - 1
IF( J.GT.1 ) THEN
IF( T( J, J-1 ).NE.ZERO ) THEN
IF( WORK( J ).GT.BIGNUM / XNORM ) THEN
X( 1, 1 ) = X( 1, 1 ) / XNORM
END IF
END IF
CALL DLALN2( .FALSE., 2, 2, SMIN, ONE,
$ T( J-1, J-1 ), LDT, ONE, ONE,
$ XNORM, IERR )
CALL DAXPY( J-2, -X( 1, 1 ), T( 1, J-1 ), 1,
$ WORK( 1+N ), 1 )
CALL DAXPY( J-2, -X( 2, 2 ), T( 1, J ), 1,
$ WORK( 1+N2 ), 1 )
END IF
90 CONTINUE
END
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