Refactor ?GEBAL (Reference-LAPACK PR 808)

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Martin Kroeker 2023-04-03 15:02:10 +02:00 committed by GitHub
parent 5f1fb27c40
commit d175b8f56f
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4 changed files with 648 additions and 568 deletions

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@ -85,6 +85,7 @@
*> \verbatim *> \verbatim
*> ILO is INTEGER *> ILO is INTEGER
*> \endverbatim *> \endverbatim
*>
*> \param[out] IHI *> \param[out] IHI
*> \verbatim *> \verbatim
*> IHI is INTEGER *> IHI is INTEGER
@ -154,6 +155,9 @@
*> *>
*> Modified by Tzu-Yi Chen, Computer Science Division, University of *> Modified by Tzu-Yi Chen, Computer Science Division, University of
*> California at Berkeley, USA *> California at Berkeley, USA
*>
*> Refactored by Evert Provoost, Department of Computer Science,
*> KU Leuven, Belgium
*> \endverbatim *> \endverbatim
*> *>
* ===================================================================== * =====================================================================
@ -183,8 +187,8 @@
PARAMETER ( FACTOR = 0.95E+0 ) PARAMETER ( FACTOR = 0.95E+0 )
* .. * ..
* .. Local Scalars .. * .. Local Scalars ..
LOGICAL NOCONV LOGICAL NOCONV, CANSWAP
INTEGER I, ICA, IEXC, IRA, J, K, L, M INTEGER I, ICA, IRA, J, K, L
REAL C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1, REAL C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1,
$ SFMIN2 $ SFMIN2
* .. * ..
@ -195,10 +199,10 @@
EXTERNAL SISNAN, LSAME, ICAMAX, SLAMCH, SCNRM2 EXTERNAL SISNAN, LSAME, ICAMAX, SLAMCH, SCNRM2
* .. * ..
* .. External Subroutines .. * .. External Subroutines ..
EXTERNAL CSSCAL, CSWAP, XERBLA EXTERNAL XERBLA, CSSCAL, CSWAP
* .. * ..
* .. Intrinsic Functions .. * .. Intrinsic Functions ..
INTRINSIC ABS, AIMAG, MAX, MIN, REAL INTRINSIC ABS, REAL, AIMAG, MAX, MIN
* *
* Test the input parameters * Test the input parameters
* *
@ -215,107 +219,132 @@
CALL XERBLA( 'CGEBAL', -INFO ) CALL XERBLA( 'CGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
* Quick returns.
*
IF( N.EQ.0 ) THEN
ILO = 1
IHI = 0
RETURN
END IF
*
IF( LSAME( JOB, 'N' ) ) THEN
DO I = 1, N
SCALE( I ) = ONE
END DO
ILO = 1
IHI = N
RETURN
END IF
*
* Permutation to isolate eigenvalues if possible.
* *
K = 1 K = 1
L = N L = N
* *
IF( N.EQ.0 ) IF( .NOT.LSAME( JOB, 'S' ) ) THEN
$ GO TO 210
*
IF( LSAME( JOB, 'N' ) ) THEN
DO 10 I = 1, N
SCALE( I ) = ONE
10 CONTINUE
GO TO 210
END IF
*
IF( LSAME( JOB, 'S' ) )
$ GO TO 120
*
* Permutation to isolate eigenvalues if possible
*
GO TO 50
* *
* Row and column exchange. * Row and column exchange.
* *
20 CONTINUE NOCONV = .TRUE.
SCALE( M ) = J DO WHILE( NOCONV )
IF( J.EQ.M )
$ GO TO 30
*
CALL CSWAP( L, A( 1, J ), 1, A( 1, M ), 1 )
CALL CSWAP( N-K+1, A( J, K ), LDA, A( M, K ), LDA )
*
30 CONTINUE
GO TO ( 40, 80 )IEXC
* *
* Search for rows isolating an eigenvalue and push them down. * Search for rows isolating an eigenvalue and push them down.
* *
40 CONTINUE NOCONV = .FALSE.
IF( L.EQ.1 ) DO I = L, 1, -1
$ GO TO 210 CANSWAP = .TRUE.
DO J = 1, L
IF( I.NE.J .AND. ( REAL( A( I, J ) ).NE.ZERO .OR.
$ AIMAG( A( I, J ) ).NE.ZERO ) ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( L ) = I
IF( I.NE.L ) THEN
CALL CSWAP( L, A( 1, I ), 1, A( 1, L ), 1 )
CALL CSWAP( N-K+1, A( I, K ), LDA, A( L, K ), LDA )
END IF
NOCONV = .TRUE.
*
IF( L.EQ.1 ) THEN
ILO = 1
IHI = 1
RETURN
END IF
*
L = L - 1 L = L - 1
END IF
END DO
* *
50 CONTINUE END DO
DO 70 J = L, 1, -1
* NOCONV = .TRUE.
DO 60 I = 1, L DO WHILE( NOCONV )
IF( I.EQ.J )
$ GO TO 60
IF( REAL( A( J, I ) ).NE.ZERO .OR. AIMAG( A( J, I ) ).NE.
$ ZERO )GO TO 70
60 CONTINUE
*
M = L
IEXC = 1
GO TO 20
70 CONTINUE
*
GO TO 90
* *
* Search for columns isolating an eigenvalue and push them left. * Search for columns isolating an eigenvalue and push them left.
* *
80 CONTINUE NOCONV = .FALSE.
DO J = K, L
CANSWAP = .TRUE.
DO I = K, L
IF( I.NE.J .AND. ( REAL( A( I, J ) ).NE.ZERO .OR.
$ AIMAG( A( I, J ) ).NE.ZERO ) ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( K ) = J
IF( J.NE.K ) THEN
CALL CSWAP( L, A( 1, J ), 1, A( 1, K ), 1 )
CALL CSWAP( N-K+1, A( J, K ), LDA, A( K, K ), LDA )
END IF
NOCONV = .TRUE.
*
K = K + 1 K = K + 1
END IF
END DO
* *
90 CONTINUE END DO
DO 110 J = K, L
* *
DO 100 I = K, L END IF
IF( I.EQ.J )
$ GO TO 100
IF( REAL( A( I, J ) ).NE.ZERO .OR. AIMAG( A( I, J ) ).NE.
$ ZERO )GO TO 110
100 CONTINUE
* *
M = K * Initialize SCALE for non-permuted submatrix.
IEXC = 2
GO TO 20
110 CONTINUE
* *
120 CONTINUE DO I = K, L
DO 130 I = K, L
SCALE( I ) = ONE SCALE( I ) = ONE
130 CONTINUE END DO
* *
IF( LSAME( JOB, 'P' ) ) * If we only had to permute, we are done.
$ GO TO 210 *
IF( LSAME( JOB, 'P' ) ) THEN
ILO = K
IHI = L
RETURN
END IF
* *
* Balance the submatrix in rows K to L. * Balance the submatrix in rows K to L.
* *
* Iterative loop for norm reduction * Iterative loop for norm reduction.
* *
SFMIN1 = SLAMCH( 'S' ) / SLAMCH( 'P' ) SFMIN1 = SLAMCH( 'S' ) / SLAMCH( 'P' )
SFMAX1 = ONE / SFMIN1 SFMAX1 = ONE / SFMIN1
SFMIN2 = SFMIN1*SCLFAC SFMIN2 = SFMIN1*SCLFAC
SFMAX2 = ONE / SFMIN2 SFMAX2 = ONE / SFMIN2
140 CONTINUE *
NOCONV = .TRUE.
DO WHILE( NOCONV )
NOCONV = .FALSE. NOCONV = .FALSE.
* *
DO 200 I = K, L DO I = K, L
* *
C = SCNRM2( L-K+1, A( K, I ), 1 ) C = SCNRM2( L-K+1, A( K, I ), 1 )
R = SCNRM2( L-K+1, A( I , K ), LDA ) R = SCNRM2( L-K+1, A( I, K ), LDA )
ICA = ICAMAX( L, A( 1, I ), 1 ) ICA = ICAMAX( L, A( 1, I ), 1 )
CA = ABS( A( ICA, I ) ) CA = ABS( A( ICA, I ) )
IRA = ICAMAX( N-K+1, A( I, K ), LDA ) IRA = ICAMAX( N-K+1, A( I, K ), LDA )
@ -323,55 +352,50 @@
* *
* Guard against zero C or R due to underflow. * Guard against zero C or R due to underflow.
* *
IF( C.EQ.ZERO .OR. R.EQ.ZERO ) IF( C.EQ.ZERO .OR. R.EQ.ZERO ) CYCLE
$ GO TO 200
G = R / SCLFAC
F = ONE
S = C + R
160 CONTINUE
IF( C.GE.G .OR. MAX( F, C, CA ).GE.SFMAX2 .OR.
$ MIN( R, G, RA ).LE.SFMIN2 )GO TO 170
IF( SISNAN( C+F+CA+R+G+RA ) ) THEN
* *
* Exit if NaN to avoid infinite loop * Exit if NaN to avoid infinite loop
* *
IF( SISNAN( C+CA+R+RA ) ) THEN
INFO = -3 INFO = -3
CALL XERBLA( 'CGEBAL', -INFO ) CALL XERBLA( 'CGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
G = R / SCLFAC
F = ONE
S = C + R
*
DO WHILE( C.LT.G .AND. MAX( F, C, CA ).LT.SFMAX2 .AND.
$ MIN( R, G, RA ).GT.SFMIN2 )
F = F*SCLFAC F = F*SCLFAC
C = C*SCLFAC C = C*SCLFAC
CA = CA*SCLFAC CA = CA*SCLFAC
R = R / SCLFAC R = R / SCLFAC
G = G / SCLFAC G = G / SCLFAC
RA = RA / SCLFAC RA = RA / SCLFAC
GO TO 160 END DO
* *
170 CONTINUE
G = C / SCLFAC G = C / SCLFAC
180 CONTINUE *
IF( G.LT.R .OR. MAX( R, RA ).GE.SFMAX2 .OR. DO WHILE( G.GE.R .AND. MAX( R, RA ).LT.SFMAX2 .AND.
$ MIN( F, C, G, CA ).LE.SFMIN2 )GO TO 190 $ MIN( F, C, G, CA ).GT.SFMIN2 )
F = F / SCLFAC F = F / SCLFAC
C = C / SCLFAC C = C / SCLFAC
G = G / SCLFAC G = G / SCLFAC
CA = CA / SCLFAC CA = CA / SCLFAC
R = R*SCLFAC R = R*SCLFAC
RA = RA*SCLFAC RA = RA*SCLFAC
GO TO 180 END DO
* *
* Now balance. * Now balance.
* *
190 CONTINUE IF( ( C+R ).GE.FACTOR*S ) CYCLE
IF( ( C+R ).GE.FACTOR*S )
$ GO TO 200
IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN
IF( F*SCALE( I ).LE.SFMIN1 ) IF( F*SCALE( I ).LE.SFMIN1 ) CYCLE
$ GO TO 200
END IF END IF
IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN
IF( SCALE( I ).GE.SFMAX1 / F ) IF( SCALE( I ).GE.SFMAX1 / F ) CYCLE
$ GO TO 200
END IF END IF
G = ONE / F G = ONE / F
SCALE( I ) = SCALE( I )*F SCALE( I ) = SCALE( I )*F
@ -380,12 +404,10 @@
CALL CSSCAL( N-K+1, G, A( I, K ), LDA ) CALL CSSCAL( N-K+1, G, A( I, K ), LDA )
CALL CSSCAL( L, F, A( 1, I ), 1 ) CALL CSSCAL( L, F, A( 1, I ), 1 )
* *
200 CONTINUE END DO
* *
IF( NOCONV ) END DO
$ GO TO 140
* *
210 CONTINUE
ILO = K ILO = K
IHI = L IHI = L
* *

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@ -153,6 +153,9 @@
*> *>
*> Modified by Tzu-Yi Chen, Computer Science Division, University of *> Modified by Tzu-Yi Chen, Computer Science Division, University of
*> California at Berkeley, USA *> California at Berkeley, USA
*>
*> Refactored by Evert Provoost, Department of Computer Science,
*> KU Leuven, Belgium
*> \endverbatim *> \endverbatim
*> *>
* ===================================================================== * =====================================================================
@ -181,8 +184,8 @@
PARAMETER ( FACTOR = 0.95D+0 ) PARAMETER ( FACTOR = 0.95D+0 )
* .. * ..
* .. Local Scalars .. * .. Local Scalars ..
LOGICAL NOCONV LOGICAL NOCONV, CANSWAP
INTEGER I, ICA, IEXC, IRA, J, K, L, M INTEGER I, ICA, IRA, J, K, L
DOUBLE PRECISION C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1, DOUBLE PRECISION C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1,
$ SFMIN2 $ SFMIN2
* .. * ..
@ -213,105 +216,127 @@
CALL XERBLA( 'DGEBAL', -INFO ) CALL XERBLA( 'DGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
* Quick returns.
*
IF( N.EQ.0 ) THEN
ILO = 1
IHI = 0
RETURN
END IF
*
IF( LSAME( JOB, 'N' ) ) THEN
DO I = 1, N
SCALE( I ) = ONE
END DO
ILO = 1
IHI = N
RETURN
END IF
*
* Permutation to isolate eigenvalues if possible.
* *
K = 1 K = 1
L = N L = N
* *
IF( N.EQ.0 ) IF( .NOT.LSAME( JOB, 'S' ) ) THEN
$ GO TO 210
*
IF( LSAME( JOB, 'N' ) ) THEN
DO 10 I = 1, N
SCALE( I ) = ONE
10 CONTINUE
GO TO 210
END IF
*
IF( LSAME( JOB, 'S' ) )
$ GO TO 120
*
* Permutation to isolate eigenvalues if possible
*
GO TO 50
* *
* Row and column exchange. * Row and column exchange.
* *
20 CONTINUE NOCONV = .TRUE.
SCALE( M ) = J DO WHILE( NOCONV )
IF( J.EQ.M )
$ GO TO 30
*
CALL DSWAP( L, A( 1, J ), 1, A( 1, M ), 1 )
CALL DSWAP( N-K+1, A( J, K ), LDA, A( M, K ), LDA )
*
30 CONTINUE
GO TO ( 40, 80 )IEXC
* *
* Search for rows isolating an eigenvalue and push them down. * Search for rows isolating an eigenvalue and push them down.
* *
40 CONTINUE NOCONV = .FALSE.
IF( L.EQ.1 ) DO I = L, 1, -1
$ GO TO 210 CANSWAP = .TRUE.
DO J = 1, L
IF( I.NE.J .AND. A( I, J ).NE.ZERO ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( L ) = I
IF( I.NE.L ) THEN
CALL DSWAP( L, A( 1, I ), 1, A( 1, L ), 1 )
CALL DSWAP( N-K+1, A( I, K ), LDA, A( L, K ), LDA )
END IF
NOCONV = .TRUE.
*
IF( L.EQ.1 ) THEN
ILO = 1
IHI = 1
RETURN
END IF
*
L = L - 1 L = L - 1
END IF
END DO
* *
50 CONTINUE END DO
DO 70 J = L, 1, -1
* NOCONV = .TRUE.
DO 60 I = 1, L DO WHILE( NOCONV )
IF( I.EQ.J )
$ GO TO 60
IF( A( J, I ).NE.ZERO )
$ GO TO 70
60 CONTINUE
*
M = L
IEXC = 1
GO TO 20
70 CONTINUE
*
GO TO 90
* *
* Search for columns isolating an eigenvalue and push them left. * Search for columns isolating an eigenvalue and push them left.
* *
80 CONTINUE NOCONV = .FALSE.
DO J = K, L
CANSWAP = .TRUE.
DO I = K, L
IF( I.NE.J .AND. A( I, J ).NE.ZERO ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( K ) = J
IF( J.NE.K ) THEN
CALL DSWAP( L, A( 1, J ), 1, A( 1, K ), 1 )
CALL DSWAP( N-K+1, A( J, K ), LDA, A( K, K ), LDA )
END IF
NOCONV = .TRUE.
*
K = K + 1 K = K + 1
END IF
END DO
* *
90 CONTINUE END DO
DO 110 J = K, L
* *
DO 100 I = K, L END IF
IF( I.EQ.J )
$ GO TO 100
IF( A( I, J ).NE.ZERO )
$ GO TO 110
100 CONTINUE
* *
M = K * Initialize SCALE for non-permuted submatrix.
IEXC = 2
GO TO 20
110 CONTINUE
* *
120 CONTINUE DO I = K, L
DO 130 I = K, L
SCALE( I ) = ONE SCALE( I ) = ONE
130 CONTINUE END DO
* *
IF( LSAME( JOB, 'P' ) ) * If we only had to permute, we are done.
$ GO TO 210 *
IF( LSAME( JOB, 'P' ) ) THEN
ILO = K
IHI = L
RETURN
END IF
* *
* Balance the submatrix in rows K to L. * Balance the submatrix in rows K to L.
* *
* Iterative loop for norm reduction * Iterative loop for norm reduction.
* *
SFMIN1 = DLAMCH( 'S' ) / DLAMCH( 'P' ) SFMIN1 = DLAMCH( 'S' ) / DLAMCH( 'P' )
SFMAX1 = ONE / SFMIN1 SFMAX1 = ONE / SFMIN1
SFMIN2 = SFMIN1*SCLFAC SFMIN2 = SFMIN1*SCLFAC
SFMAX2 = ONE / SFMIN2 SFMAX2 = ONE / SFMIN2
* *
140 CONTINUE NOCONV = .TRUE.
DO WHILE( NOCONV )
NOCONV = .FALSE. NOCONV = .FALSE.
* *
DO 200 I = K, L DO I = K, L
* *
C = DNRM2( L-K+1, A( K, I ), 1 ) C = DNRM2( L-K+1, A( K, I ), 1 )
R = DNRM2( L-K+1, A( I, K ), LDA ) R = DNRM2( L-K+1, A( I, K ), LDA )
@ -322,55 +347,50 @@
* *
* Guard against zero C or R due to underflow. * Guard against zero C or R due to underflow.
* *
IF( C.EQ.ZERO .OR. R.EQ.ZERO ) IF( C.EQ.ZERO .OR. R.EQ.ZERO ) CYCLE
$ GO TO 200
G = R / SCLFAC
F = ONE
S = C + R
160 CONTINUE
IF( C.GE.G .OR. MAX( F, C, CA ).GE.SFMAX2 .OR.
$ MIN( R, G, RA ).LE.SFMIN2 )GO TO 170
IF( DISNAN( C+F+CA+R+G+RA ) ) THEN
* *
* Exit if NaN to avoid infinite loop * Exit if NaN to avoid infinite loop
* *
IF( DISNAN( C+CA+R+RA ) ) THEN
INFO = -3 INFO = -3
CALL XERBLA( 'DGEBAL', -INFO ) CALL XERBLA( 'DGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
G = R / SCLFAC
F = ONE
S = C + R
*
DO WHILE( C.LT.G .AND. MAX( F, C, CA ).LT.SFMAX2 .AND.
$ MIN( R, G, RA ).GT.SFMIN2 )
F = F*SCLFAC F = F*SCLFAC
C = C*SCLFAC C = C*SCLFAC
CA = CA*SCLFAC CA = CA*SCLFAC
R = R / SCLFAC R = R / SCLFAC
G = G / SCLFAC G = G / SCLFAC
RA = RA / SCLFAC RA = RA / SCLFAC
GO TO 160 END DO
* *
170 CONTINUE
G = C / SCLFAC G = C / SCLFAC
180 CONTINUE *
IF( G.LT.R .OR. MAX( R, RA ).GE.SFMAX2 .OR. DO WHILE( G.GE.R .AND. MAX( R, RA ).LT.SFMAX2 .AND.
$ MIN( F, C, G, CA ).LE.SFMIN2 )GO TO 190 $ MIN( F, C, G, CA ).GT.SFMIN2 )
F = F / SCLFAC F = F / SCLFAC
C = C / SCLFAC C = C / SCLFAC
G = G / SCLFAC G = G / SCLFAC
CA = CA / SCLFAC CA = CA / SCLFAC
R = R*SCLFAC R = R*SCLFAC
RA = RA*SCLFAC RA = RA*SCLFAC
GO TO 180 END DO
* *
* Now balance. * Now balance.
* *
190 CONTINUE IF( ( C+R ).GE.FACTOR*S ) CYCLE
IF( ( C+R ).GE.FACTOR*S )
$ GO TO 200
IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN
IF( F*SCALE( I ).LE.SFMIN1 ) IF( F*SCALE( I ).LE.SFMIN1 ) CYCLE
$ GO TO 200
END IF END IF
IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN
IF( SCALE( I ).GE.SFMAX1 / F ) IF( SCALE( I ).GE.SFMAX1 / F ) CYCLE
$ GO TO 200
END IF END IF
G = ONE / F G = ONE / F
SCALE( I ) = SCALE( I )*F SCALE( I ) = SCALE( I )*F
@ -379,12 +399,10 @@
CALL DSCAL( N-K+1, G, A( I, K ), LDA ) CALL DSCAL( N-K+1, G, A( I, K ), LDA )
CALL DSCAL( L, F, A( 1, I ), 1 ) CALL DSCAL( L, F, A( 1, I ), 1 )
* *
200 CONTINUE END DO
* *
IF( NOCONV ) END DO
$ GO TO 140
* *
210 CONTINUE
ILO = K ILO = K
IHI = L IHI = L
* *

View File

@ -153,6 +153,9 @@
*> *>
*> Modified by Tzu-Yi Chen, Computer Science Division, University of *> Modified by Tzu-Yi Chen, Computer Science Division, University of
*> California at Berkeley, USA *> California at Berkeley, USA
*>
*> Refactored by Evert Provoost, Department of Computer Science,
*> KU Leuven, Belgium
*> \endverbatim *> \endverbatim
*> *>
* ===================================================================== * =====================================================================
@ -181,8 +184,8 @@
PARAMETER ( FACTOR = 0.95E+0 ) PARAMETER ( FACTOR = 0.95E+0 )
* .. * ..
* .. Local Scalars .. * .. Local Scalars ..
LOGICAL NOCONV LOGICAL NOCONV, CANSWAP
INTEGER I, ICA, IEXC, IRA, J, K, L, M INTEGER I, ICA, IRA, J, K, L
REAL C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1, REAL C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1,
$ SFMIN2 $ SFMIN2
* .. * ..
@ -197,7 +200,7 @@
* .. * ..
* .. Intrinsic Functions .. * .. Intrinsic Functions ..
INTRINSIC ABS, MAX, MIN INTRINSIC ABS, MAX, MIN
* * ..
* Test the input parameters * Test the input parameters
* *
INFO = 0 INFO = 0
@ -213,104 +216,127 @@
CALL XERBLA( 'SGEBAL', -INFO ) CALL XERBLA( 'SGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
* Quick returns.
*
IF( N.EQ.0 ) THEN
ILO = 1
IHI = 0
RETURN
END IF
*
IF( LSAME( JOB, 'N' ) ) THEN
DO I = 1, N
SCALE( I ) = ONE
END DO
ILO = 1
IHI = N
RETURN
END IF
*
* Permutation to isolate eigenvalues if possible.
* *
K = 1 K = 1
L = N L = N
* *
IF( N.EQ.0 ) IF( .NOT.LSAME( JOB, 'S' ) ) THEN
$ GO TO 210
*
IF( LSAME( JOB, 'N' ) ) THEN
DO 10 I = 1, N
SCALE( I ) = ONE
10 CONTINUE
GO TO 210
END IF
*
IF( LSAME( JOB, 'S' ) )
$ GO TO 120
*
* Permutation to isolate eigenvalues if possible
*
GO TO 50
* *
* Row and column exchange. * Row and column exchange.
* *
20 CONTINUE NOCONV = .TRUE.
SCALE( M ) = J DO WHILE( NOCONV )
IF( J.EQ.M )
$ GO TO 30
*
CALL SSWAP( L, A( 1, J ), 1, A( 1, M ), 1 )
CALL SSWAP( N-K+1, A( J, K ), LDA, A( M, K ), LDA )
*
30 CONTINUE
GO TO ( 40, 80 )IEXC
* *
* Search for rows isolating an eigenvalue and push them down. * Search for rows isolating an eigenvalue and push them down.
* *
40 CONTINUE NOCONV = .FALSE.
IF( L.EQ.1 ) DO I = L, 1, -1
$ GO TO 210 CANSWAP = .TRUE.
DO J = 1, L
IF( I.NE.J .AND. A( I, J ).NE.ZERO ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( L ) = I
IF( I.NE.L ) THEN
CALL SSWAP( L, A( 1, I ), 1, A( 1, L ), 1 )
CALL SSWAP( N-K+1, A( I, K ), LDA, A( L, K ), LDA )
END IF
NOCONV = .TRUE.
*
IF( L.EQ.1 ) THEN
ILO = 1
IHI = 1
RETURN
END IF
*
L = L - 1 L = L - 1
END IF
END DO
* *
50 CONTINUE END DO
DO 70 J = L, 1, -1
* NOCONV = .TRUE.
DO 60 I = 1, L DO WHILE( NOCONV )
IF( I.EQ.J )
$ GO TO 60
IF( A( J, I ).NE.ZERO )
$ GO TO 70
60 CONTINUE
*
M = L
IEXC = 1
GO TO 20
70 CONTINUE
*
GO TO 90
* *
* Search for columns isolating an eigenvalue and push them left. * Search for columns isolating an eigenvalue and push them left.
* *
80 CONTINUE NOCONV = .FALSE.
DO J = K, L
CANSWAP = .TRUE.
DO I = K, L
IF( I.NE.J .AND. A( I, J ).NE.ZERO ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( K ) = J
IF( J.NE.K ) THEN
CALL SSWAP( L, A( 1, J ), 1, A( 1, K ), 1 )
CALL SSWAP( N-K+1, A( J, K ), LDA, A( K, K ), LDA )
END IF
NOCONV = .TRUE.
*
K = K + 1 K = K + 1
END IF
END DO
* *
90 CONTINUE END DO
DO 110 J = K, L
* *
DO 100 I = K, L END IF
IF( I.EQ.J )
$ GO TO 100
IF( A( I, J ).NE.ZERO )
$ GO TO 110
100 CONTINUE
* *
M = K * Initialize SCALE for non-permuted submatrix.
IEXC = 2
GO TO 20
110 CONTINUE
* *
120 CONTINUE DO I = K, L
DO 130 I = K, L
SCALE( I ) = ONE SCALE( I ) = ONE
130 CONTINUE END DO
* *
IF( LSAME( JOB, 'P' ) ) * If we only had to permute, we are done.
$ GO TO 210 *
IF( LSAME( JOB, 'P' ) ) THEN
ILO = K
IHI = L
RETURN
END IF
* *
* Balance the submatrix in rows K to L. * Balance the submatrix in rows K to L.
* *
* Iterative loop for norm reduction * Iterative loop for norm reduction.
* *
SFMIN1 = SLAMCH( 'S' ) / SLAMCH( 'P' ) SFMIN1 = SLAMCH( 'S' ) / SLAMCH( 'P' )
SFMAX1 = ONE / SFMIN1 SFMAX1 = ONE / SFMIN1
SFMIN2 = SFMIN1*SCLFAC SFMIN2 = SFMIN1*SCLFAC
SFMAX2 = ONE / SFMIN2 SFMAX2 = ONE / SFMIN2
140 CONTINUE *
NOCONV = .TRUE.
DO WHILE( NOCONV )
NOCONV = .FALSE. NOCONV = .FALSE.
* *
DO 200 I = K, L DO I = K, L
* *
C = SNRM2( L-K+1, A( K, I ), 1 ) C = SNRM2( L-K+1, A( K, I ), 1 )
R = SNRM2( L-K+1, A( I, K ), LDA ) R = SNRM2( L-K+1, A( I, K ), LDA )
@ -321,55 +347,50 @@
* *
* Guard against zero C or R due to underflow. * Guard against zero C or R due to underflow.
* *
IF( C.EQ.ZERO .OR. R.EQ.ZERO ) IF( C.EQ.ZERO .OR. R.EQ.ZERO ) CYCLE
$ GO TO 200 *
* Exit if NaN to avoid infinite loop
*
IF( SISNAN( C+CA+R+RA ) ) THEN
INFO = -3
CALL XERBLA( 'SGEBAL', -INFO )
RETURN
END IF
*
G = R / SCLFAC G = R / SCLFAC
F = ONE F = ONE
S = C + R S = C + R
160 CONTINUE *
IF( C.GE.G .OR. MAX( F, C, CA ).GE.SFMAX2 .OR. DO WHILE( C.LT.G .AND. MAX( F, C, CA ).LT.SFMAX2 .AND.
$ MIN( R, G, RA ).LE.SFMIN2 )GO TO 170 $ MIN( R, G, RA ).GT.SFMIN2 )
F = F*SCLFAC F = F*SCLFAC
C = C*SCLFAC C = C*SCLFAC
CA = CA*SCLFAC CA = CA*SCLFAC
R = R / SCLFAC R = R / SCLFAC
G = G / SCLFAC G = G / SCLFAC
RA = RA / SCLFAC RA = RA / SCLFAC
GO TO 160 END DO
* *
170 CONTINUE
G = C / SCLFAC G = C / SCLFAC
180 CONTINUE
IF( G.LT.R .OR. MAX( R, RA ).GE.SFMAX2 .OR.
$ MIN( F, C, G, CA ).LE.SFMIN2 )GO TO 190
IF( SISNAN( C+F+CA+R+G+RA ) ) THEN
* *
* Exit if NaN to avoid infinite loop DO WHILE( G.GE.R .AND. MAX( R, RA ).LT.SFMAX2 .AND.
* $ MIN( F, C, G, CA ).GT.SFMIN2 )
INFO = -3
CALL XERBLA( 'SGEBAL', -INFO )
RETURN
END IF
F = F / SCLFAC F = F / SCLFAC
C = C / SCLFAC C = C / SCLFAC
G = G / SCLFAC G = G / SCLFAC
CA = CA / SCLFAC CA = CA / SCLFAC
R = R*SCLFAC R = R*SCLFAC
RA = RA*SCLFAC RA = RA*SCLFAC
GO TO 180 END DO
* *
* Now balance. * Now balance.
* *
190 CONTINUE IF( ( C+R ).GE.FACTOR*S ) CYCLE
IF( ( C+R ).GE.FACTOR*S )
$ GO TO 200
IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN
IF( F*SCALE( I ).LE.SFMIN1 ) IF( F*SCALE( I ).LE.SFMIN1 ) CYCLE
$ GO TO 200
END IF END IF
IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN
IF( SCALE( I ).GE.SFMAX1 / F ) IF( SCALE( I ).GE.SFMAX1 / F ) CYCLE
$ GO TO 200
END IF END IF
G = ONE / F G = ONE / F
SCALE( I ) = SCALE( I )*F SCALE( I ) = SCALE( I )*F
@ -378,12 +399,10 @@
CALL SSCAL( N-K+1, G, A( I, K ), LDA ) CALL SSCAL( N-K+1, G, A( I, K ), LDA )
CALL SSCAL( L, F, A( 1, I ), 1 ) CALL SSCAL( L, F, A( 1, I ), 1 )
* *
200 CONTINUE END DO
* *
IF( NOCONV ) END DO
$ GO TO 140
* *
210 CONTINUE
ILO = K ILO = K
IHI = L IHI = L
* *

View File

@ -89,7 +89,7 @@
*> \param[out] IHI *> \param[out] IHI
*> \verbatim *> \verbatim
*> IHI is INTEGER *> IHI is INTEGER
*> ILO and IHI are set to INTEGER such that on exit *> ILO and IHI are set to integers such that on exit
*> A(i,j) = 0 if i > j and j = 1,...,ILO-1 or I = IHI+1,...,N. *> A(i,j) = 0 if i > j and j = 1,...,ILO-1 or I = IHI+1,...,N.
*> If JOB = 'N' or 'S', ILO = 1 and IHI = N. *> If JOB = 'N' or 'S', ILO = 1 and IHI = N.
*> \endverbatim *> \endverbatim
@ -155,6 +155,9 @@
*> *>
*> Modified by Tzu-Yi Chen, Computer Science Division, University of *> Modified by Tzu-Yi Chen, Computer Science Division, University of
*> California at Berkeley, USA *> California at Berkeley, USA
*>
*> Refactored by Evert Provoost, Department of Computer Science,
*> KU Leuven, Belgium
*> \endverbatim *> \endverbatim
*> *>
* ===================================================================== * =====================================================================
@ -184,8 +187,8 @@
PARAMETER ( FACTOR = 0.95D+0 ) PARAMETER ( FACTOR = 0.95D+0 )
* .. * ..
* .. Local Scalars .. * .. Local Scalars ..
LOGICAL NOCONV LOGICAL NOCONV, CANSWAP
INTEGER I, ICA, IEXC, IRA, J, K, L, M INTEGER I, ICA, IRA, J, K, L
DOUBLE PRECISION C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1, DOUBLE PRECISION C, CA, F, G, R, RA, S, SFMAX1, SFMAX2, SFMIN1,
$ SFMIN2 $ SFMIN2
* .. * ..
@ -216,104 +219,129 @@
CALL XERBLA( 'ZGEBAL', -INFO ) CALL XERBLA( 'ZGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
* Quick returns.
*
IF( N.EQ.0 ) THEN
ILO = 1
IHI = 0
RETURN
END IF
*
IF( LSAME( JOB, 'N' ) ) THEN
DO I = 1, N
SCALE( I ) = ONE
END DO
ILO = 1
IHI = N
RETURN
END IF
*
* Permutation to isolate eigenvalues if possible.
* *
K = 1 K = 1
L = N L = N
* *
IF( N.EQ.0 ) IF( .NOT.LSAME( JOB, 'S' ) ) THEN
$ GO TO 210
*
IF( LSAME( JOB, 'N' ) ) THEN
DO 10 I = 1, N
SCALE( I ) = ONE
10 CONTINUE
GO TO 210
END IF
*
IF( LSAME( JOB, 'S' ) )
$ GO TO 120
*
* Permutation to isolate eigenvalues if possible
*
GO TO 50
* *
* Row and column exchange. * Row and column exchange.
* *
20 CONTINUE NOCONV = .TRUE.
SCALE( M ) = J DO WHILE( NOCONV )
IF( J.EQ.M )
$ GO TO 30
*
CALL ZSWAP( L, A( 1, J ), 1, A( 1, M ), 1 )
CALL ZSWAP( N-K+1, A( J, K ), LDA, A( M, K ), LDA )
*
30 CONTINUE
GO TO ( 40, 80 )IEXC
* *
* Search for rows isolating an eigenvalue and push them down. * Search for rows isolating an eigenvalue and push them down.
* *
40 CONTINUE NOCONV = .FALSE.
IF( L.EQ.1 ) DO I = L, 1, -1
$ GO TO 210 CANSWAP = .TRUE.
DO J = 1, L
IF( I.NE.J .AND. ( DBLE( A( I, J ) ).NE.ZERO .OR.
$ DIMAG( A( I, J ) ).NE.ZERO ) ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( L ) = I
IF( I.NE.L ) THEN
CALL ZSWAP( L, A( 1, I ), 1, A( 1, L ), 1 )
CALL ZSWAP( N-K+1, A( I, K ), LDA, A( L, K ), LDA )
END IF
NOCONV = .TRUE.
*
IF( L.EQ.1 ) THEN
ILO = 1
IHI = 1
RETURN
END IF
*
L = L - 1 L = L - 1
END IF
END DO
* *
50 CONTINUE END DO
DO 70 J = L, 1, -1
* NOCONV = .TRUE.
DO 60 I = 1, L DO WHILE( NOCONV )
IF( I.EQ.J )
$ GO TO 60
IF( DBLE( A( J, I ) ).NE.ZERO .OR. DIMAG( A( J, I ) ).NE.
$ ZERO )GO TO 70
60 CONTINUE
*
M = L
IEXC = 1
GO TO 20
70 CONTINUE
*
GO TO 90
* *
* Search for columns isolating an eigenvalue and push them left. * Search for columns isolating an eigenvalue and push them left.
* *
80 CONTINUE NOCONV = .FALSE.
DO J = K, L
CANSWAP = .TRUE.
DO I = K, L
IF( I.NE.J .AND. ( DBLE( A( I, J ) ).NE.ZERO .OR.
$ DIMAG( A( I, J ) ).NE.ZERO ) ) THEN
CANSWAP = .FALSE.
EXIT
END IF
END DO
*
IF( CANSWAP ) THEN
SCALE( K ) = J
IF( J.NE.K ) THEN
CALL ZSWAP( L, A( 1, J ), 1, A( 1, K ), 1 )
CALL ZSWAP( N-K+1, A( J, K ), LDA, A( K, K ), LDA )
END IF
NOCONV = .TRUE.
*
K = K + 1 K = K + 1
END IF
END DO
* *
90 CONTINUE END DO
DO 110 J = K, L
* *
DO 100 I = K, L END IF
IF( I.EQ.J )
$ GO TO 100
IF( DBLE( A( I, J ) ).NE.ZERO .OR. DIMAG( A( I, J ) ).NE.
$ ZERO )GO TO 110
100 CONTINUE
* *
M = K * Initialize SCALE for non-permuted submatrix.
IEXC = 2
GO TO 20
110 CONTINUE
* *
120 CONTINUE DO I = K, L
DO 130 I = K, L
SCALE( I ) = ONE SCALE( I ) = ONE
130 CONTINUE END DO
* *
IF( LSAME( JOB, 'P' ) ) * If we only had to permute, we are done.
$ GO TO 210 *
IF( LSAME( JOB, 'P' ) ) THEN
ILO = K
IHI = L
RETURN
END IF
* *
* Balance the submatrix in rows K to L. * Balance the submatrix in rows K to L.
* *
* Iterative loop for norm reduction * Iterative loop for norm reduction.
* *
SFMIN1 = DLAMCH( 'S' ) / DLAMCH( 'P' ) SFMIN1 = DLAMCH( 'S' ) / DLAMCH( 'P' )
SFMAX1 = ONE / SFMIN1 SFMAX1 = ONE / SFMIN1
SFMIN2 = SFMIN1*SCLFAC SFMIN2 = SFMIN1*SCLFAC
SFMAX2 = ONE / SFMIN2 SFMAX2 = ONE / SFMIN2
140 CONTINUE *
NOCONV = .TRUE.
DO WHILE( NOCONV )
NOCONV = .FALSE. NOCONV = .FALSE.
* *
DO 200 I = K, L DO I = K, L
* *
C = DZNRM2( L-K+1, A( K, I ), 1 ) C = DZNRM2( L-K+1, A( K, I ), 1 )
R = DZNRM2( L-K+1, A( I, K ), LDA ) R = DZNRM2( L-K+1, A( I, K ), LDA )
@ -324,55 +352,50 @@
* *
* Guard against zero C or R due to underflow. * Guard against zero C or R due to underflow.
* *
IF( C.EQ.ZERO .OR. R.EQ.ZERO ) IF( C.EQ.ZERO .OR. R.EQ.ZERO ) CYCLE
$ GO TO 200
G = R / SCLFAC
F = ONE
S = C + R
160 CONTINUE
IF( C.GE.G .OR. MAX( F, C, CA ).GE.SFMAX2 .OR.
$ MIN( R, G, RA ).LE.SFMIN2 )GO TO 170
IF( DISNAN( C+F+CA+R+G+RA ) ) THEN
* *
* Exit if NaN to avoid infinite loop * Exit if NaN to avoid infinite loop
* *
IF( DISNAN( C+CA+R+RA ) ) THEN
INFO = -3 INFO = -3
CALL XERBLA( 'ZGEBAL', -INFO ) CALL XERBLA( 'ZGEBAL', -INFO )
RETURN RETURN
END IF END IF
*
G = R / SCLFAC
F = ONE
S = C + R
*
DO WHILE( C.LT.G .AND. MAX( F, C, CA ).LT.SFMAX2 .AND.
$ MIN( R, G, RA ).GT.SFMIN2 )
F = F*SCLFAC F = F*SCLFAC
C = C*SCLFAC C = C*SCLFAC
CA = CA*SCLFAC CA = CA*SCLFAC
R = R / SCLFAC R = R / SCLFAC
G = G / SCLFAC G = G / SCLFAC
RA = RA / SCLFAC RA = RA / SCLFAC
GO TO 160 END DO
* *
170 CONTINUE
G = C / SCLFAC G = C / SCLFAC
180 CONTINUE *
IF( G.LT.R .OR. MAX( R, RA ).GE.SFMAX2 .OR. DO WHILE( G.GE.R .AND. MAX( R, RA ).LT.SFMAX2 .AND.
$ MIN( F, C, G, CA ).LE.SFMIN2 )GO TO 190 $ MIN( F, C, G, CA ).GT.SFMIN2 )
F = F / SCLFAC F = F / SCLFAC
C = C / SCLFAC C = C / SCLFAC
G = G / SCLFAC G = G / SCLFAC
CA = CA / SCLFAC CA = CA / SCLFAC
R = R*SCLFAC R = R*SCLFAC
RA = RA*SCLFAC RA = RA*SCLFAC
GO TO 180 END DO
* *
* Now balance. * Now balance.
* *
190 CONTINUE IF( ( C+R ).GE.FACTOR*S ) CYCLE
IF( ( C+R ).GE.FACTOR*S )
$ GO TO 200
IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN IF( F.LT.ONE .AND. SCALE( I ).LT.ONE ) THEN
IF( F*SCALE( I ).LE.SFMIN1 ) IF( F*SCALE( I ).LE.SFMIN1 ) CYCLE
$ GO TO 200
END IF END IF
IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN IF( F.GT.ONE .AND. SCALE( I ).GT.ONE ) THEN
IF( SCALE( I ).GE.SFMAX1 / F ) IF( SCALE( I ).GE.SFMAX1 / F ) CYCLE
$ GO TO 200
END IF END IF
G = ONE / F G = ONE / F
SCALE( I ) = SCALE( I )*F SCALE( I ) = SCALE( I )*F
@ -381,12 +404,10 @@
CALL ZDSCAL( N-K+1, G, A( I, K ), LDA ) CALL ZDSCAL( N-K+1, G, A( I, K ), LDA )
CALL ZDSCAL( L, F, A( 1, I ), 1 ) CALL ZDSCAL( L, F, A( 1, I ), 1 )
* *
200 CONTINUE END DO
* *
IF( NOCONV ) END DO
$ GO TO 140
* *
210 CONTINUE
ILO = K ILO = K
IHI = L IHI = L
* *