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author | jofret | 2009-04-28 07:17:00 +0000 |
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committer | jofret | 2009-04-28 07:17:00 +0000 |
commit | 8c8d2f518968ce7057eec6aa5cd5aec8faab861a (patch) | |
tree | 3dd1788b71d6a3ce2b73d2d475a3133580e17530 /src/lib/lapack/dlatdf.f | |
parent | 9f652ffc16a310ac6641a9766c5b9e2671e0e9cb (diff) | |
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Moving lapack to right place
Diffstat (limited to 'src/lib/lapack/dlatdf.f')
-rw-r--r-- | src/lib/lapack/dlatdf.f | 237 |
1 files changed, 0 insertions, 237 deletions
diff --git a/src/lib/lapack/dlatdf.f b/src/lib/lapack/dlatdf.f deleted file mode 100644 index 91fa46e3..00000000 --- a/src/lib/lapack/dlatdf.f +++ /dev/null @@ -1,237 +0,0 @@ - SUBROUTINE DLATDF( IJOB, N, Z, LDZ, RHS, RDSUM, RDSCAL, IPIV, - $ JPIV ) -* -* -- LAPACK auxiliary routine (version 3.1) -- -* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. -* November 2006 -* -* .. Scalar Arguments .. - INTEGER IJOB, LDZ, N - DOUBLE PRECISION RDSCAL, RDSUM -* .. -* .. Array Arguments .. - INTEGER IPIV( * ), JPIV( * ) - DOUBLE PRECISION RHS( * ), Z( LDZ, * ) -* .. -* -* Purpose -* ======= -* -* DLATDF uses the LU factorization of the n-by-n matrix Z computed by -* DGETC2 and computes a contribution to the reciprocal Dif-estimate -* by solving Z * x = b for x, and choosing the r.h.s. b such that -* the norm of x is as large as possible. On entry RHS = b holds the -* contribution from earlier solved sub-systems, and on return RHS = x. -* -* The factorization of Z returned by DGETC2 has the form Z = P*L*U*Q, -* where P and Q are permutation matrices. L is lower triangular with -* unit diagonal elements and U is upper triangular. -* -* Arguments -* ========= -* -* IJOB (input) INTEGER -* IJOB = 2: First compute an approximative null-vector e -* of Z using DGECON, e is normalized and solve for -* Zx = +-e - f with the sign giving the greater value -* of 2-norm(x). About 5 times as expensive as Default. -* IJOB .ne. 2: Local look ahead strategy where all entries of -* the r.h.s. b is choosen as either +1 or -1 (Default). -* -* N (input) INTEGER -* The number of columns of the matrix Z. -* -* Z (input) DOUBLE PRECISION array, dimension (LDZ, N) -* On entry, the LU part of the factorization of the n-by-n -* matrix Z computed by DGETC2: Z = P * L * U * Q -* -* LDZ (input) INTEGER -* The leading dimension of the array Z. LDA >= max(1, N). -* -* RHS (input/output) DOUBLE PRECISION array, dimension N. -* On entry, RHS contains contributions from other subsystems. -* On exit, RHS contains the solution of the subsystem with -* entries acoording to the value of IJOB (see above). -* -* RDSUM (input/output) DOUBLE PRECISION -* On entry, the sum of squares of computed contributions to -* the Dif-estimate under computation by DTGSYL, where the -* scaling factor RDSCAL (see below) has been factored out. -* On exit, the corresponding sum of squares updated with the -* contributions from the current sub-system. -* If TRANS = 'T' RDSUM is not touched. -* NOTE: RDSUM only makes sense when DTGSY2 is called by STGSYL. -* -* RDSCAL (input/output) DOUBLE PRECISION -* On entry, scaling factor used to prevent overflow in RDSUM. -* On exit, RDSCAL is updated w.r.t. the current contributions -* in RDSUM. -* If TRANS = 'T', RDSCAL is not touched. -* NOTE: RDSCAL only makes sense when DTGSY2 is called by -* DTGSYL. -* -* IPIV (input) INTEGER array, dimension (N). -* The pivot indices; for 1 <= i <= N, row i of the -* matrix has been interchanged with row IPIV(i). -* -* JPIV (input) INTEGER array, dimension (N). -* The pivot indices; for 1 <= j <= N, column j of the -* matrix has been interchanged with column JPIV(j). -* -* Further Details -* =============== -* -* Based on contributions by -* Bo Kagstrom and Peter Poromaa, Department of Computing Science, -* Umea University, S-901 87 Umea, Sweden. -* -* This routine is a further developed implementation of algorithm -* BSOLVE in [1] using complete pivoting in the LU factorization. -* -* [1] Bo Kagstrom and Lars Westin, -* Generalized Schur Methods with Condition Estimators for -* Solving the Generalized Sylvester Equation, IEEE Transactions -* on Automatic Control, Vol. 34, No. 7, July 1989, pp 745-751. -* -* [2] Peter Poromaa, -* On Efficient and Robust Estimators for the Separation -* between two Regular Matrix Pairs with Applications in -* Condition Estimation. Report IMINF-95.05, Departement of -* Computing Science, Umea University, S-901 87 Umea, Sweden, 1995. -* -* ===================================================================== -* -* .. Parameters .. - INTEGER MAXDIM - PARAMETER ( MAXDIM = 8 ) - DOUBLE PRECISION ZERO, ONE - PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) -* .. -* .. Local Scalars .. - INTEGER I, INFO, J, K - DOUBLE PRECISION BM, BP, PMONE, SMINU, SPLUS, TEMP -* .. -* .. Local Arrays .. - INTEGER IWORK( MAXDIM ) - DOUBLE PRECISION WORK( 4*MAXDIM ), XM( MAXDIM ), XP( MAXDIM ) -* .. -* .. External Subroutines .. - EXTERNAL DAXPY, DCOPY, DGECON, DGESC2, DLASSQ, DLASWP, - $ DSCAL -* .. -* .. External Functions .. - DOUBLE PRECISION DASUM, DDOT - EXTERNAL DASUM, DDOT -* .. -* .. Intrinsic Functions .. - INTRINSIC ABS, SQRT -* .. -* .. Executable Statements .. -* - IF( IJOB.NE.2 ) THEN -* -* Apply permutations IPIV to RHS -* - CALL DLASWP( 1, RHS, LDZ, 1, N-1, IPIV, 1 ) -* -* Solve for L-part choosing RHS either to +1 or -1. -* - PMONE = -ONE -* - DO 10 J = 1, N - 1 - BP = RHS( J ) + ONE - BM = RHS( J ) - ONE - SPLUS = ONE -* -* Look-ahead for L-part RHS(1:N-1) = + or -1, SPLUS and -* SMIN computed more efficiently than in BSOLVE [1]. -* - SPLUS = SPLUS + DDOT( N-J, Z( J+1, J ), 1, Z( J+1, J ), 1 ) - SMINU = DDOT( N-J, Z( J+1, J ), 1, RHS( J+1 ), 1 ) - SPLUS = SPLUS*RHS( J ) - IF( SPLUS.GT.SMINU ) THEN - RHS( J ) = BP - ELSE IF( SMINU.GT.SPLUS ) THEN - RHS( J ) = BM - ELSE -* -* In this case the updating sums are equal and we can -* choose RHS(J) +1 or -1. The first time this happens -* we choose -1, thereafter +1. This is a simple way to -* get good estimates of matrices like Byers well-known -* example (see [1]). (Not done in BSOLVE.) -* - RHS( J ) = RHS( J ) + PMONE - PMONE = ONE - END IF -* -* Compute the remaining r.h.s. -* - TEMP = -RHS( J ) - CALL DAXPY( N-J, TEMP, Z( J+1, J ), 1, RHS( J+1 ), 1 ) -* - 10 CONTINUE -* -* Solve for U-part, look-ahead for RHS(N) = +-1. This is not done -* in BSOLVE and will hopefully give us a better estimate because -* any ill-conditioning of the original matrix is transfered to U -* and not to L. U(N, N) is an approximation to sigma_min(LU). -* - CALL DCOPY( N-1, RHS, 1, XP, 1 ) - XP( N ) = RHS( N ) + ONE - RHS( N ) = RHS( N ) - ONE - SPLUS = ZERO - SMINU = ZERO - DO 30 I = N, 1, -1 - TEMP = ONE / Z( I, I ) - XP( I ) = XP( I )*TEMP - RHS( I ) = RHS( I )*TEMP - DO 20 K = I + 1, N - XP( I ) = XP( I ) - XP( K )*( Z( I, K )*TEMP ) - RHS( I ) = RHS( I ) - RHS( K )*( Z( I, K )*TEMP ) - 20 CONTINUE - SPLUS = SPLUS + ABS( XP( I ) ) - SMINU = SMINU + ABS( RHS( I ) ) - 30 CONTINUE - IF( SPLUS.GT.SMINU ) - $ CALL DCOPY( N, XP, 1, RHS, 1 ) -* -* Apply the permutations JPIV to the computed solution (RHS) -* - CALL DLASWP( 1, RHS, LDZ, 1, N-1, JPIV, -1 ) -* -* Compute the sum of squares -* - CALL DLASSQ( N, RHS, 1, RDSCAL, RDSUM ) -* - ELSE -* -* IJOB = 2, Compute approximate nullvector XM of Z -* - CALL DGECON( 'I', N, Z, LDZ, ONE, TEMP, WORK, IWORK, INFO ) - CALL DCOPY( N, WORK( N+1 ), 1, XM, 1 ) -* -* Compute RHS -* - CALL DLASWP( 1, XM, LDZ, 1, N-1, IPIV, -1 ) - TEMP = ONE / SQRT( DDOT( N, XM, 1, XM, 1 ) ) - CALL DSCAL( N, TEMP, XM, 1 ) - CALL DCOPY( N, XM, 1, XP, 1 ) - CALL DAXPY( N, ONE, RHS, 1, XP, 1 ) - CALL DAXPY( N, -ONE, XM, 1, RHS, 1 ) - CALL DGESC2( N, Z, LDZ, RHS, IPIV, JPIV, TEMP ) - CALL DGESC2( N, Z, LDZ, XP, IPIV, JPIV, TEMP ) - IF( DASUM( N, XP, 1 ).GT.DASUM( N, RHS, 1 ) ) - $ CALL DCOPY( N, XP, 1, RHS, 1 ) -* -* Compute the sum of squares -* - CALL DLASSQ( N, RHS, 1, RDSCAL, RDSUM ) -* - END IF -* - RETURN -* -* End of DLATDF -* - END |