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version 1.8, 2010/12/21 13:53:37
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version 1.9, 2011/07/22 07:38:10
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| SUBROUTINE DSGESV( N, NRHS, A, LDA, IPIV, B, LDB, X, LDX, WORK, |
SUBROUTINE DSGESV( N, NRHS, A, LDA, IPIV, B, LDB, X, LDX, WORK, |
| + SWORK, ITER, INFO ) |
$ SWORK, ITER, INFO ) |
| * |
* |
| * -- LAPACK PROTOTYPE driver routine (version 3.2.2) -- |
* -- LAPACK PROTOTYPE driver routine (version 3.3.1) -- |
| * -- 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..-- |
| * February 2007 |
* -- April 2011 -- |
| * |
* |
| * .. |
* .. |
| * .. Scalar Arguments .. |
* .. Scalar Arguments .. |
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| INTEGER IPIV( * ) |
INTEGER IPIV( * ) |
| REAL SWORK( * ) |
REAL SWORK( * ) |
| DOUBLE PRECISION A( LDA, * ), B( LDB, * ), WORK( N, * ), |
DOUBLE PRECISION A( LDA, * ), B( LDB, * ), WORK( N, * ), |
| + X( LDX, * ) |
$ X( LDX, * ) |
| * .. |
* .. |
| * |
* |
| * Purpose |
* Purpose |
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| * but the factor U is exactly singular, so the solution |
* but the factor U is exactly singular, so the solution |
| * could not be computed. |
* could not be computed. |
| * |
* |
| * ========= |
* ===================================================================== |
| * |
* |
| * .. Parameters .. |
* .. Parameters .. |
| LOGICAL DOITREF |
LOGICAL DOITREF |
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| * |
* |
| * .. External Subroutines .. |
* .. External Subroutines .. |
| EXTERNAL DAXPY, DGEMM, DLACPY, DLAG2S, SLAG2D, SGETRF, |
EXTERNAL DAXPY, DGEMM, DLACPY, DLAG2S, SLAG2D, SGETRF, |
| + SGETRS, XERBLA |
$ SGETRS, XERBLA |
| * .. |
* .. |
| * .. External Functions .. |
* .. External Functions .. |
| INTEGER IDAMAX |
INTEGER IDAMAX |
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| * Quick return if (N.EQ.0). |
* Quick return if (N.EQ.0). |
| * |
* |
| IF( N.EQ.0 ) |
IF( N.EQ.0 ) |
| + RETURN |
$ RETURN |
| * |
* |
| * Skip single precision iterative refinement if a priori slower |
* Skip single precision iterative refinement if a priori slower |
| * than double precision factorization. |
* than double precision factorization. |
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| * Solve the system SA*SX = SB. |
* Solve the system SA*SX = SB. |
| * |
* |
| CALL SGETRS( 'No transpose', N, NRHS, SWORK( PTSA ), N, IPIV, |
CALL SGETRS( 'No transpose', N, NRHS, SWORK( PTSA ), N, IPIV, |
| + SWORK( PTSX ), N, INFO ) |
$ SWORK( PTSX ), N, INFO ) |
| * |
* |
| * Convert SX back to double precision |
* Convert SX back to double precision |
| * |
* |
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| CALL DLACPY( 'All', N, NRHS, B, LDB, WORK, N ) |
CALL DLACPY( 'All', N, NRHS, B, LDB, WORK, N ) |
| * |
* |
| CALL DGEMM( 'No Transpose', 'No Transpose', N, NRHS, N, NEGONE, A, |
CALL DGEMM( 'No Transpose', 'No Transpose', N, NRHS, N, NEGONE, A, |
| + LDA, X, LDX, ONE, WORK, N ) |
$ LDA, X, LDX, ONE, WORK, N ) |
| * |
* |
| * Check whether the NRHS normwise backward errors satisfy the |
* Check whether the NRHS normwise backward errors satisfy the |
| * stopping criterion. If yes, set ITER=0 and return. |
* stopping criterion. If yes, set ITER=0 and return. |
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| XNRM = ABS( X( IDAMAX( N, X( 1, I ), 1 ), I ) ) |
XNRM = ABS( X( IDAMAX( N, X( 1, I ), 1 ), I ) ) |
| RNRM = ABS( WORK( IDAMAX( N, WORK( 1, I ), 1 ), I ) ) |
RNRM = ABS( WORK( IDAMAX( N, WORK( 1, I ), 1 ), I ) ) |
| IF( RNRM.GT.XNRM*CTE ) |
IF( RNRM.GT.XNRM*CTE ) |
| + GO TO 10 |
$ GO TO 10 |
| END DO |
END DO |
| * |
* |
| * If we are here, the NRHS normwise backward errors satisfy the |
* If we are here, the NRHS normwise backward errors satisfy the |
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| * Solve the system SA*SX = SR. |
* Solve the system SA*SX = SR. |
| * |
* |
| CALL SGETRS( 'No transpose', N, NRHS, SWORK( PTSA ), N, IPIV, |
CALL SGETRS( 'No transpose', N, NRHS, SWORK( PTSA ), N, IPIV, |
| + SWORK( PTSX ), N, INFO ) |
$ SWORK( PTSX ), N, INFO ) |
| * |
* |
| * Convert SX back to double precision and update the current |
* Convert SX back to double precision and update the current |
| * iterate. |
* iterate. |
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| CALL DLACPY( 'All', N, NRHS, B, LDB, WORK, N ) |
CALL DLACPY( 'All', N, NRHS, B, LDB, WORK, N ) |
| * |
* |
| CALL DGEMM( 'No Transpose', 'No Transpose', N, NRHS, N, NEGONE, |
CALL DGEMM( 'No Transpose', 'No Transpose', N, NRHS, N, NEGONE, |
| + A, LDA, X, LDX, ONE, WORK, N ) |
$ A, LDA, X, LDX, ONE, WORK, N ) |
| * |
* |
| * Check whether the NRHS normwise backward errors satisfy the |
* Check whether the NRHS normwise backward errors satisfy the |
| * stopping criterion. If yes, set ITER=IITER>0 and return. |
* stopping criterion. If yes, set ITER=IITER>0 and return. |
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| XNRM = ABS( X( IDAMAX( N, X( 1, I ), 1 ), I ) ) |
XNRM = ABS( X( IDAMAX( N, X( 1, I ), 1 ), I ) ) |
| RNRM = ABS( WORK( IDAMAX( N, WORK( 1, I ), 1 ), I ) ) |
RNRM = ABS( WORK( IDAMAX( N, WORK( 1, I ), 1 ), I ) ) |
| IF( RNRM.GT.XNRM*CTE ) |
IF( RNRM.GT.XNRM*CTE ) |
| + GO TO 20 |
$ GO TO 20 |
| END DO |
END DO |
| * |
* |
| * If we are here, the NRHS normwise backward errors satisfy the |
* If we are here, the NRHS normwise backward errors satisfy the |
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| CALL DGETRF( N, N, A, LDA, IPIV, INFO ) |
CALL DGETRF( N, N, A, LDA, IPIV, INFO ) |
| * |
* |
| IF( INFO.NE.0 ) |
IF( INFO.NE.0 ) |
| + RETURN |
$ RETURN |
| * |
* |
| CALL DLACPY( 'All', N, NRHS, B, LDB, X, LDX ) |
CALL DLACPY( 'All', N, NRHS, B, LDB, X, LDX ) |
| CALL DGETRS( 'No transpose', N, NRHS, A, LDA, IPIV, X, LDX, |
CALL DGETRS( 'No transpose', N, NRHS, A, LDA, IPIV, X, LDX, |
| + INFO ) |
$ INFO ) |
| * |
* |
| RETURN |
RETURN |
| * |
* |
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