1DLAQR1(1)           LAPACK auxiliary routine (version 3.1)           DLAQR1(1)
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NAME

SYNOPSIS

7       SUBROUTINE DLAQR1( N, H, LDH, SR1, SI1, SR2, SI2, V )
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9           DOUBLE         PRECISION SI1, SI2, SR1, SR2
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11           INTEGER        LDH, N
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13           DOUBLE         PRECISION H( LDH, * ), V( * )
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15           DOUBLE         PRECISION ZERO
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17           PARAMETER      ( ZERO = 0.0d0 )
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19           DOUBLE         PRECISION H21S, H31S, S
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21           INTRINSIC      ABS
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23           IF(            N.EQ.2 ) THEN
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25           S              = ABS( H( 1, 1 )-SR2 ) + ABS( SI2 ) + ABS( H( 2, 1 )
26                          )
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28           IF(            S.EQ.ZERO ) THEN
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30           V(             1 ) = ZERO
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32           V(             2 ) = ZERO
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34           ELSE
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36           H21S           = H( 2, 1 ) / S
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38           V(             1 ) = H21S*H( 1, 2 ) + ( H( 1, 1 )-SR1 )* ( ( H(  1,
39                          1 )-SR2 ) / S ) - SI1*( SI2 / S )
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41           V(             2 ) = H21S*( H( 1, 1 )+H( 2, 2 )-SR1-SR2 )
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43           END            IF
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45           ELSE
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47           S              = ABS( H( 1, 1 )-SR2 ) + ABS( SI2 ) + ABS( H( 2, 1 )
48                          ) + ABS( H( 3, 1 ) )
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50           IF(            S.EQ.ZERO ) THEN
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52           V(             1 ) = ZERO
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54           V(             2 ) = ZERO
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56           V(             3 ) = ZERO
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58           ELSE
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60           H21S           = H( 2, 1 ) / S
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62           H31S           = H( 3, 1 ) / S
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64           V(             1 ) = ( H( 1, 1 )-SR1 )*( ( H( 1, 1 )-SR2 ) / S )  -
65                          SI1*( SI2 / S ) + H( 1, 2 )*H21S + H( 1, 3 )*H31S
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67           V(             2 ) = H21S*( H( 1, 1 )+H( 2, 2 )-SR1-SR2 ) + H( 2, 3
68                          )*H31S
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70           V(             3 ) = H31S*( H( 1, 1 )+H( 3, 3 )-SR1-SR2 ) + H21S*H(
71                          3, 2 )
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73           END            IF
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75           END            IF
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77           END
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PURPOSE

80 LAPACK auxiliary routine (versionNo3v.e1m)ber 2006                       DLAQR1(1)