version 1.15, 2016/08/27 15:27:10
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version 1.19, 2018/05/29 06:55:20
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* |
* |
* =========== DOCUMENTATION =========== |
* =========== DOCUMENTATION =========== |
* |
* |
* Online html documentation available at |
* Online html documentation available at |
* http://www.netlib.org/lapack/explore-html/ |
* http://www.netlib.org/lapack/explore-html/ |
* |
* |
*> \htmlonly |
*> \htmlonly |
*> Download DLASQ4 + dependencies |
*> Download DLASQ4 + dependencies |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlasq4.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlasq4.f"> |
*> [TGZ]</a> |
*> [TGZ]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlasq4.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlasq4.f"> |
*> [ZIP]</a> |
*> [ZIP]</a> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlasq4.f"> |
*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlasq4.f"> |
*> [TXT]</a> |
*> [TXT]</a> |
*> \endhtmlonly |
*> \endhtmlonly |
* |
* |
* Definition: |
* Definition: |
* =========== |
* =========== |
* |
* |
* SUBROUTINE DLASQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, |
* SUBROUTINE DLASQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, |
* DN1, DN2, TAU, TTYPE, G ) |
* DN1, DN2, TAU, TTYPE, G ) |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
* INTEGER I0, N0, N0IN, PP, TTYPE |
* INTEGER I0, N0, N0IN, PP, TTYPE |
* DOUBLE PRECISION DMIN, DMIN1, DMIN2, DN, DN1, DN2, G, TAU |
* DOUBLE PRECISION DMIN, DMIN1, DMIN2, DN, DN1, DN2, G, TAU |
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* .. Array Arguments .. |
* .. Array Arguments .. |
* DOUBLE PRECISION Z( * ) |
* DOUBLE PRECISION Z( * ) |
* .. |
* .. |
* |
* |
* |
* |
*> \par Purpose: |
*> \par Purpose: |
* ============= |
* ============= |
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* Authors: |
* Authors: |
* ======== |
* ======== |
* |
* |
*> \author Univ. of Tennessee |
*> \author Univ. of Tennessee |
*> \author Univ. of California Berkeley |
*> \author Univ. of California Berkeley |
*> \author Univ. of Colorado Denver |
*> \author Univ. of Colorado Denver |
*> \author NAG Ltd. |
*> \author NAG Ltd. |
* |
* |
*> \date June 2016 |
*> \date June 2016 |
* |
* |
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SUBROUTINE DLASQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, |
SUBROUTINE DLASQ4( I0, N0, Z, PP, N0IN, DMIN, DMIN1, DMIN2, DN, |
$ DN1, DN2, TAU, TTYPE, G ) |
$ DN1, DN2, TAU, TTYPE, G ) |
* |
* |
* -- LAPACK computational routine (version 3.6.1) -- |
* -- LAPACK computational routine (version 3.7.1) -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* June 2016 |
* June 2016 |
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TTYPE = -1 |
TTYPE = -1 |
RETURN |
RETURN |
END IF |
END IF |
* |
* |
NN = 4*N0 + PP |
NN = 4*N0 + PP |
IF( N0IN.EQ.N0 ) THEN |
IF( N0IN.EQ.N0 ) THEN |
* |
* |
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NP = NN - 9 |
NP = NN - 9 |
ELSE |
ELSE |
NP = NN - 2*PP |
NP = NN - 2*PP |
B2 = Z( NP-2 ) |
|
GAM = DN1 |
GAM = DN1 |
IF( Z( NP-4 ) .GT. Z( NP-2 ) ) |
IF( Z( NP-4 ) .GT. Z( NP-2 ) ) |
$ RETURN |
$ RETURN |
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$ RETURN |
$ RETURN |
B2 = B2*( Z( I4 ) / Z( I4-2 ) ) |
B2 = B2*( Z( I4 ) / Z( I4-2 ) ) |
A2 = A2 + B2 |
A2 = A2 + B2 |
IF( HUNDRD*MAX( B2, B1 ).LT.A2 .OR. CNST1.LT.A2 ) |
IF( HUNDRD*MAX( B2, B1 ).LT.A2 .OR. CNST1.LT.A2 ) |
$ GO TO 20 |
$ GO TO 20 |
10 CONTINUE |
10 CONTINUE |
20 CONTINUE |
20 CONTINUE |
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$ RETURN |
$ RETURN |
B2 = B2*( Z( I4 ) / Z( I4-2 ) ) |
B2 = B2*( Z( I4 ) / Z( I4-2 ) ) |
A2 = A2 + B2 |
A2 = A2 + B2 |
IF( HUNDRD*MAX( B2, B1 ).LT.A2 .OR. CNST1.LT.A2 ) |
IF( HUNDRD*MAX( B2, B1 ).LT.A2 .OR. CNST1.LT.A2 ) |
$ GO TO 40 |
$ GO TO 40 |
30 CONTINUE |
30 CONTINUE |
40 CONTINUE |
40 CONTINUE |
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* |
* |
* One eigenvalue just deflated. Use DMIN1, DN1 for DMIN and DN. |
* One eigenvalue just deflated. Use DMIN1, DN1 for DMIN and DN. |
* |
* |
IF( DMIN1.EQ.DN1 .AND. DMIN2.EQ.DN2 ) THEN |
IF( DMIN1.EQ.DN1 .AND. DMIN2.EQ.DN2 ) THEN |
* |
* |
* Cases 7 and 8. |
* Cases 7 and 8. |
* |
* |
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$ RETURN |
$ RETURN |
B1 = B1*( Z( I4 ) / Z( I4-2 ) ) |
B1 = B1*( Z( I4 ) / Z( I4-2 ) ) |
B2 = B2 + B1 |
B2 = B2 + B1 |
IF( HUNDRD*MAX( B1, A2 ).LT.B2 ) |
IF( HUNDRD*MAX( B1, A2 ).LT.B2 ) |
$ GO TO 60 |
$ GO TO 60 |
50 CONTINUE |
50 CONTINUE |
60 CONTINUE |
60 CONTINUE |
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GAP2 = HALF*DMIN2 - A2 |
GAP2 = HALF*DMIN2 - A2 |
IF( GAP2.GT.ZERO .AND. GAP2.GT.B2*A2 ) THEN |
IF( GAP2.GT.ZERO .AND. GAP2.GT.B2*A2 ) THEN |
S = MAX( S, A2*( ONE-CNST2*A2*( B2 / GAP2 )*B2 ) ) |
S = MAX( S, A2*( ONE-CNST2*A2*( B2 / GAP2 )*B2 ) ) |
ELSE |
ELSE |
S = MAX( S, A2*( ONE-CNST2*B2 ) ) |
S = MAX( S, A2*( ONE-CNST2*B2 ) ) |
TTYPE = -8 |
TTYPE = -8 |
END IF |
END IF |
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* |
* |
* Cases 10 and 11. |
* Cases 10 and 11. |
* |
* |
IF( DMIN2.EQ.DN2 .AND. TWO*Z( NN-5 ).LT.Z( NN-7 ) ) THEN |
IF( DMIN2.EQ.DN2 .AND. TWO*Z( NN-5 ).LT.Z( NN-7 ) ) THEN |
TTYPE = -10 |
TTYPE = -10 |
S = THIRD*DMIN2 |
S = THIRD*DMIN2 |
IF( Z( NN-5 ).GT.Z( NN-7 ) ) |
IF( Z( NN-5 ).GT.Z( NN-7 ) ) |
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$ SQRT( Z( NN-11 ) )*SQRT( Z( NN-9 ) ) - A2 |
$ SQRT( Z( NN-11 ) )*SQRT( Z( NN-9 ) ) - A2 |
IF( GAP2.GT.ZERO .AND. GAP2.GT.B2*A2 ) THEN |
IF( GAP2.GT.ZERO .AND. GAP2.GT.B2*A2 ) THEN |
S = MAX( S, A2*( ONE-CNST2*A2*( B2 / GAP2 )*B2 ) ) |
S = MAX( S, A2*( ONE-CNST2*A2*( B2 / GAP2 )*B2 ) ) |
ELSE |
ELSE |
S = MAX( S, A2*( ONE-CNST2*B2 ) ) |
S = MAX( S, A2*( ONE-CNST2*B2 ) ) |
END IF |
END IF |
ELSE |
ELSE |
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* |
* |
* Case 12, more than two eigenvalues deflated. No information. |
* Case 12, more than two eigenvalues deflated. No information. |
* |
* |
S = ZERO |
S = ZERO |
TTYPE = -12 |
TTYPE = -12 |
END IF |
END IF |
* |
* |