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authorjofret2009-04-28 07:17:00 +0000
committerjofret2009-04-28 07:17:00 +0000
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Moving lapack to right place
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- SUBROUTINE DTGSY2( TRANS, IJOB, M, N, A, LDA, B, LDB, C, LDC, D,
- $ LDD, E, LDE, F, LDF, SCALE, RDSUM, RDSCAL,
- $ IWORK, PQ, INFO )
-*
-* -- LAPACK auxiliary routine (version 3.1) --
-* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
-* November 2006
-*
-* .. Scalar Arguments ..
- CHARACTER TRANS
- INTEGER IJOB, INFO, LDA, LDB, LDC, LDD, LDE, LDF, M, N,
- $ PQ
- DOUBLE PRECISION RDSCAL, RDSUM, SCALE
-* ..
-* .. Array Arguments ..
- INTEGER IWORK( * )
- DOUBLE PRECISION A( LDA, * ), B( LDB, * ), C( LDC, * ),
- $ D( LDD, * ), E( LDE, * ), F( LDF, * )
-* ..
-*
-* Purpose
-* =======
-*
-* DTGSY2 solves the generalized Sylvester equation:
-*
-* A * R - L * B = scale * C (1)
-* D * R - L * E = scale * F,
-*
-* using Level 1 and 2 BLAS. where R and L are unknown M-by-N matrices,
-* (A, D), (B, E) and (C, F) are given matrix pairs of size M-by-M,
-* N-by-N and M-by-N, respectively, with real entries. (A, D) and (B, E)
-* must be in generalized Schur canonical form, i.e. A, B are upper
-* quasi triangular and D, E are upper triangular. The solution (R, L)
-* overwrites (C, F). 0 <= SCALE <= 1 is an output scaling factor
-* chosen to avoid overflow.
-*
-* In matrix notation solving equation (1) corresponds to solve
-* Z*x = scale*b, where Z is defined as
-*
-* Z = [ kron(In, A) -kron(B', Im) ] (2)
-* [ kron(In, D) -kron(E', Im) ],
-*
-* Ik is the identity matrix of size k and X' is the transpose of X.
-* kron(X, Y) is the Kronecker product between the matrices X and Y.
-* In the process of solving (1), we solve a number of such systems
-* where Dim(In), Dim(In) = 1 or 2.
-*
-* If TRANS = 'T', solve the transposed system Z'*y = scale*b for y,
-* which is equivalent to solve for R and L in
-*
-* A' * R + D' * L = scale * C (3)
-* R * B' + L * E' = scale * -F
-*
-* This case is used to compute an estimate of Dif[(A, D), (B, E)] =
-* sigma_min(Z) using reverse communicaton with DLACON.
-*
-* DTGSY2 also (IJOB >= 1) contributes to the computation in STGSYL
-* of an upper bound on the separation between to matrix pairs. Then
-* the input (A, D), (B, E) are sub-pencils of the matrix pair in
-* DTGSYL. See STGSYL for details.
-*
-* Arguments
-* =========
-*
-* TRANS (input) CHARACTER*1
-* = 'N', solve the generalized Sylvester equation (1).
-* = 'T': solve the 'transposed' system (3).
-*
-* IJOB (input) INTEGER
-* Specifies what kind of functionality to be performed.
-* = 0: solve (1) only.
-* = 1: A contribution from this subsystem to a Frobenius
-* norm-based estimate of the separation between two matrix
-* pairs is computed. (look ahead strategy is used).
-* = 2: A contribution from this subsystem to a Frobenius
-* norm-based estimate of the separation between two matrix
-* pairs is computed. (DGECON on sub-systems is used.)
-* Not referenced if TRANS = 'T'.
-*
-* M (input) INTEGER
-* On entry, M specifies the order of A and D, and the row
-* dimension of C, F, R and L.
-*
-* N (input) INTEGER
-* On entry, N specifies the order of B and E, and the column
-* dimension of C, F, R and L.
-*
-* A (input) DOUBLE PRECISION array, dimension (LDA, M)
-* On entry, A contains an upper quasi triangular matrix.
-*
-* LDA (input) INTEGER
-* The leading dimension of the matrix A. LDA >= max(1, M).
-*
-* B (input) DOUBLE PRECISION array, dimension (LDB, N)
-* On entry, B contains an upper quasi triangular matrix.
-*
-* LDB (input) INTEGER
-* The leading dimension of the matrix B. LDB >= max(1, N).
-*
-* C (input/output) DOUBLE PRECISION array, dimension (LDC, N)
-* On entry, C contains the right-hand-side of the first matrix
-* equation in (1).
-* On exit, if IJOB = 0, C has been overwritten by the
-* solution R.
-*
-* LDC (input) INTEGER
-* The leading dimension of the matrix C. LDC >= max(1, M).
-*
-* D (input) DOUBLE PRECISION array, dimension (LDD, M)
-* On entry, D contains an upper triangular matrix.
-*
-* LDD (input) INTEGER
-* The leading dimension of the matrix D. LDD >= max(1, M).
-*
-* E (input) DOUBLE PRECISION array, dimension (LDE, N)
-* On entry, E contains an upper triangular matrix.
-*
-* LDE (input) INTEGER
-* The leading dimension of the matrix E. LDE >= max(1, N).
-*
-* F (input/output) DOUBLE PRECISION array, dimension (LDF, N)
-* On entry, F contains the right-hand-side of the second matrix
-* equation in (1).
-* On exit, if IJOB = 0, F has been overwritten by the
-* solution L.
-*
-* LDF (input) INTEGER
-* The leading dimension of the matrix F. LDF >= max(1, M).
-*
-* SCALE (output) DOUBLE PRECISION
-* On exit, 0 <= SCALE <= 1. If 0 < SCALE < 1, the solutions
-* R and L (C and F on entry) will hold the solutions to a
-* slightly perturbed system but the input matrices A, B, D and
-* E have not been changed. If SCALE = 0, R and L will hold the
-* solutions to the homogeneous system with C = F = 0. Normally,
-* SCALE = 1.
-*
-* 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.
-*
-* IWORK (workspace) INTEGER array, dimension (M+N+2)
-*
-* PQ (output) INTEGER
-* On exit, the number of subsystems (of size 2-by-2, 4-by-4 and
-* 8-by-8) solved by this routine.
-*
-* INFO (output) INTEGER
-* On exit, if INFO is set to
-* =0: Successful exit
-* <0: If INFO = -i, the i-th argument had an illegal value.
-* >0: The matrix pairs (A, D) and (B, E) have common or very
-* close eigenvalues.
-*
-* Further Details
-* ===============
-*
-* Based on contributions by
-* Bo Kagstrom and Peter Poromaa, Department of Computing Science,
-* Umea University, S-901 87 Umea, Sweden.
-*
-* =====================================================================
-* Replaced various illegal calls to DCOPY by calls to DLASET.
-* Sven Hammarling, 27/5/02.
-*
-* .. Parameters ..
- INTEGER LDZ
- PARAMETER ( LDZ = 8 )
- DOUBLE PRECISION ZERO, ONE
- PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 )
-* ..
-* .. Local Scalars ..
- LOGICAL NOTRAN
- INTEGER I, IE, IERR, II, IS, ISP1, J, JE, JJ, JS, JSP1,
- $ K, MB, NB, P, Q, ZDIM
- DOUBLE PRECISION ALPHA, SCALOC
-* ..
-* .. Local Arrays ..
- INTEGER IPIV( LDZ ), JPIV( LDZ )
- DOUBLE PRECISION RHS( LDZ ), Z( LDZ, LDZ )
-* ..
-* .. External Functions ..
- LOGICAL LSAME
- EXTERNAL LSAME
-* ..
-* .. External Subroutines ..
- EXTERNAL DAXPY, DCOPY, DGEMM, DGEMV, DGER, DGESC2,
- $ DGETC2, DLASET, DLATDF, DSCAL, XERBLA
-* ..
-* .. Intrinsic Functions ..
- INTRINSIC MAX
-* ..
-* .. Executable Statements ..
-*
-* Decode and test input parameters
-*
- INFO = 0
- IERR = 0
- NOTRAN = LSAME( TRANS, 'N' )
- IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'T' ) ) THEN
- INFO = -1
- ELSE IF( NOTRAN ) THEN
- IF( ( IJOB.LT.0 ) .OR. ( IJOB.GT.2 ) ) THEN
- INFO = -2
- END IF
- END IF
- IF( INFO.EQ.0 ) THEN
- IF( M.LE.0 ) THEN
- INFO = -3
- ELSE IF( N.LE.0 ) THEN
- INFO = -4
- ELSE IF( LDA.LT.MAX( 1, M ) ) THEN
- INFO = -5
- ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
- INFO = -8
- ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
- INFO = -10
- ELSE IF( LDD.LT.MAX( 1, M ) ) THEN
- INFO = -12
- ELSE IF( LDE.LT.MAX( 1, N ) ) THEN
- INFO = -14
- ELSE IF( LDF.LT.MAX( 1, M ) ) THEN
- INFO = -16
- END IF
- END IF
- IF( INFO.NE.0 ) THEN
- CALL XERBLA( 'DTGSY2', -INFO )
- RETURN
- END IF
-*
-* Determine block structure of A
-*
- PQ = 0
- P = 0
- I = 1
- 10 CONTINUE
- IF( I.GT.M )
- $ GO TO 20
- P = P + 1
- IWORK( P ) = I
- IF( I.EQ.M )
- $ GO TO 20
- IF( A( I+1, I ).NE.ZERO ) THEN
- I = I + 2
- ELSE
- I = I + 1
- END IF
- GO TO 10
- 20 CONTINUE
- IWORK( P+1 ) = M + 1
-*
-* Determine block structure of B
-*
- Q = P + 1
- J = 1
- 30 CONTINUE
- IF( J.GT.N )
- $ GO TO 40
- Q = Q + 1
- IWORK( Q ) = J
- IF( J.EQ.N )
- $ GO TO 40
- IF( B( J+1, J ).NE.ZERO ) THEN
- J = J + 2
- ELSE
- J = J + 1
- END IF
- GO TO 30
- 40 CONTINUE
- IWORK( Q+1 ) = N + 1
- PQ = P*( Q-P-1 )
-*
- IF( NOTRAN ) THEN
-*
-* Solve (I, J) - subsystem
-* A(I, I) * R(I, J) - L(I, J) * B(J, J) = C(I, J)
-* D(I, I) * R(I, J) - L(I, J) * E(J, J) = F(I, J)
-* for I = P, P - 1, ..., 1; J = 1, 2, ..., Q
-*
- SCALE = ONE
- SCALOC = ONE
- DO 120 J = P + 2, Q
- JS = IWORK( J )
- JSP1 = JS + 1
- JE = IWORK( J+1 ) - 1
- NB = JE - JS + 1
- DO 110 I = P, 1, -1
-*
- IS = IWORK( I )
- ISP1 = IS + 1
- IE = IWORK( I+1 ) - 1
- MB = IE - IS + 1
- ZDIM = MB*NB*2
-*
- IF( ( MB.EQ.1 ) .AND. ( NB.EQ.1 ) ) THEN
-*
-* Build a 2-by-2 system Z * x = RHS
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = D( IS, IS )
- Z( 1, 2 ) = -B( JS, JS )
- Z( 2, 2 ) = -E( JS, JS )
-*
-* Set up right hand side(s)
-*
- RHS( 1 ) = C( IS, JS )
- RHS( 2 ) = F( IS, JS )
-*
-* Solve Z * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
-*
- IF( IJOB.EQ.0 ) THEN
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV,
- $ SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 50 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 50 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
- ELSE
- CALL DLATDF( IJOB, ZDIM, Z, LDZ, RHS, RDSUM,
- $ RDSCAL, IPIV, JPIV )
- END IF
-*
-* Unpack solution vector(s)
-*
- C( IS, JS ) = RHS( 1 )
- F( IS, JS ) = RHS( 2 )
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( I.GT.1 ) THEN
- ALPHA = -RHS( 1 )
- CALL DAXPY( IS-1, ALPHA, A( 1, IS ), 1, C( 1, JS ),
- $ 1 )
- CALL DAXPY( IS-1, ALPHA, D( 1, IS ), 1, F( 1, JS ),
- $ 1 )
- END IF
- IF( J.LT.Q ) THEN
- CALL DAXPY( N-JE, RHS( 2 ), B( JS, JE+1 ), LDB,
- $ C( IS, JE+1 ), LDC )
- CALL DAXPY( N-JE, RHS( 2 ), E( JS, JE+1 ), LDE,
- $ F( IS, JE+1 ), LDF )
- END IF
-*
- ELSE IF( ( MB.EQ.1 ) .AND. ( NB.EQ.2 ) ) THEN
-*
-* Build a 4-by-4 system Z * x = RHS
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = ZERO
- Z( 3, 1 ) = D( IS, IS )
- Z( 4, 1 ) = ZERO
-*
- Z( 1, 2 ) = ZERO
- Z( 2, 2 ) = A( IS, IS )
- Z( 3, 2 ) = ZERO
- Z( 4, 2 ) = D( IS, IS )
-*
- Z( 1, 3 ) = -B( JS, JS )
- Z( 2, 3 ) = -B( JS, JSP1 )
- Z( 3, 3 ) = -E( JS, JS )
- Z( 4, 3 ) = -E( JS, JSP1 )
-*
- Z( 1, 4 ) = -B( JSP1, JS )
- Z( 2, 4 ) = -B( JSP1, JSP1 )
- Z( 3, 4 ) = ZERO
- Z( 4, 4 ) = -E( JSP1, JSP1 )
-*
-* Set up right hand side(s)
-*
- RHS( 1 ) = C( IS, JS )
- RHS( 2 ) = C( IS, JSP1 )
- RHS( 3 ) = F( IS, JS )
- RHS( 4 ) = F( IS, JSP1 )
-*
-* Solve Z * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
-*
- IF( IJOB.EQ.0 ) THEN
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV,
- $ SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 60 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 60 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
- ELSE
- CALL DLATDF( IJOB, ZDIM, Z, LDZ, RHS, RDSUM,
- $ RDSCAL, IPIV, JPIV )
- END IF
-*
-* Unpack solution vector(s)
-*
- C( IS, JS ) = RHS( 1 )
- C( IS, JSP1 ) = RHS( 2 )
- F( IS, JS ) = RHS( 3 )
- F( IS, JSP1 ) = RHS( 4 )
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( I.GT.1 ) THEN
- CALL DGER( IS-1, NB, -ONE, A( 1, IS ), 1, RHS( 1 ),
- $ 1, C( 1, JS ), LDC )
- CALL DGER( IS-1, NB, -ONE, D( 1, IS ), 1, RHS( 1 ),
- $ 1, F( 1, JS ), LDF )
- END IF
- IF( J.LT.Q ) THEN
- CALL DAXPY( N-JE, RHS( 3 ), B( JS, JE+1 ), LDB,
- $ C( IS, JE+1 ), LDC )
- CALL DAXPY( N-JE, RHS( 3 ), E( JS, JE+1 ), LDE,
- $ F( IS, JE+1 ), LDF )
- CALL DAXPY( N-JE, RHS( 4 ), B( JSP1, JE+1 ), LDB,
- $ C( IS, JE+1 ), LDC )
- CALL DAXPY( N-JE, RHS( 4 ), E( JSP1, JE+1 ), LDE,
- $ F( IS, JE+1 ), LDF )
- END IF
-*
- ELSE IF( ( MB.EQ.2 ) .AND. ( NB.EQ.1 ) ) THEN
-*
-* Build a 4-by-4 system Z * x = RHS
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = A( ISP1, IS )
- Z( 3, 1 ) = D( IS, IS )
- Z( 4, 1 ) = ZERO
-*
- Z( 1, 2 ) = A( IS, ISP1 )
- Z( 2, 2 ) = A( ISP1, ISP1 )
- Z( 3, 2 ) = D( IS, ISP1 )
- Z( 4, 2 ) = D( ISP1, ISP1 )
-*
- Z( 1, 3 ) = -B( JS, JS )
- Z( 2, 3 ) = ZERO
- Z( 3, 3 ) = -E( JS, JS )
- Z( 4, 3 ) = ZERO
-*
- Z( 1, 4 ) = ZERO
- Z( 2, 4 ) = -B( JS, JS )
- Z( 3, 4 ) = ZERO
- Z( 4, 4 ) = -E( JS, JS )
-*
-* Set up right hand side(s)
-*
- RHS( 1 ) = C( IS, JS )
- RHS( 2 ) = C( ISP1, JS )
- RHS( 3 ) = F( IS, JS )
- RHS( 4 ) = F( ISP1, JS )
-*
-* Solve Z * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
- IF( IJOB.EQ.0 ) THEN
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV,
- $ SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 70 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 70 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
- ELSE
- CALL DLATDF( IJOB, ZDIM, Z, LDZ, RHS, RDSUM,
- $ RDSCAL, IPIV, JPIV )
- END IF
-*
-* Unpack solution vector(s)
-*
- C( IS, JS ) = RHS( 1 )
- C( ISP1, JS ) = RHS( 2 )
- F( IS, JS ) = RHS( 3 )
- F( ISP1, JS ) = RHS( 4 )
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( I.GT.1 ) THEN
- CALL DGEMV( 'N', IS-1, MB, -ONE, A( 1, IS ), LDA,
- $ RHS( 1 ), 1, ONE, C( 1, JS ), 1 )
- CALL DGEMV( 'N', IS-1, MB, -ONE, D( 1, IS ), LDD,
- $ RHS( 1 ), 1, ONE, F( 1, JS ), 1 )
- END IF
- IF( J.LT.Q ) THEN
- CALL DGER( MB, N-JE, ONE, RHS( 3 ), 1,
- $ B( JS, JE+1 ), LDB, C( IS, JE+1 ), LDC )
- CALL DGER( MB, N-JE, ONE, RHS( 3 ), 1,
- $ E( JS, JE+1 ), LDB, F( IS, JE+1 ), LDC )
- END IF
-*
- ELSE IF( ( MB.EQ.2 ) .AND. ( NB.EQ.2 ) ) THEN
-*
-* Build an 8-by-8 system Z * x = RHS
-*
- CALL DLASET( 'F', LDZ, LDZ, ZERO, ZERO, Z, LDZ )
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = A( ISP1, IS )
- Z( 5, 1 ) = D( IS, IS )
-*
- Z( 1, 2 ) = A( IS, ISP1 )
- Z( 2, 2 ) = A( ISP1, ISP1 )
- Z( 5, 2 ) = D( IS, ISP1 )
- Z( 6, 2 ) = D( ISP1, ISP1 )
-*
- Z( 3, 3 ) = A( IS, IS )
- Z( 4, 3 ) = A( ISP1, IS )
- Z( 7, 3 ) = D( IS, IS )
-*
- Z( 3, 4 ) = A( IS, ISP1 )
- Z( 4, 4 ) = A( ISP1, ISP1 )
- Z( 7, 4 ) = D( IS, ISP1 )
- Z( 8, 4 ) = D( ISP1, ISP1 )
-*
- Z( 1, 5 ) = -B( JS, JS )
- Z( 3, 5 ) = -B( JS, JSP1 )
- Z( 5, 5 ) = -E( JS, JS )
- Z( 7, 5 ) = -E( JS, JSP1 )
-*
- Z( 2, 6 ) = -B( JS, JS )
- Z( 4, 6 ) = -B( JS, JSP1 )
- Z( 6, 6 ) = -E( JS, JS )
- Z( 8, 6 ) = -E( JS, JSP1 )
-*
- Z( 1, 7 ) = -B( JSP1, JS )
- Z( 3, 7 ) = -B( JSP1, JSP1 )
- Z( 7, 7 ) = -E( JSP1, JSP1 )
-*
- Z( 2, 8 ) = -B( JSP1, JS )
- Z( 4, 8 ) = -B( JSP1, JSP1 )
- Z( 8, 8 ) = -E( JSP1, JSP1 )
-*
-* Set up right hand side(s)
-*
- K = 1
- II = MB*NB + 1
- DO 80 JJ = 0, NB - 1
- CALL DCOPY( MB, C( IS, JS+JJ ), 1, RHS( K ), 1 )
- CALL DCOPY( MB, F( IS, JS+JJ ), 1, RHS( II ), 1 )
- K = K + MB
- II = II + MB
- 80 CONTINUE
-*
-* Solve Z * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
- IF( IJOB.EQ.0 ) THEN
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV,
- $ SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 90 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 90 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
- ELSE
- CALL DLATDF( IJOB, ZDIM, Z, LDZ, RHS, RDSUM,
- $ RDSCAL, IPIV, JPIV )
- END IF
-*
-* Unpack solution vector(s)
-*
- K = 1
- II = MB*NB + 1
- DO 100 JJ = 0, NB - 1
- CALL DCOPY( MB, RHS( K ), 1, C( IS, JS+JJ ), 1 )
- CALL DCOPY( MB, RHS( II ), 1, F( IS, JS+JJ ), 1 )
- K = K + MB
- II = II + MB
- 100 CONTINUE
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( I.GT.1 ) THEN
- CALL DGEMM( 'N', 'N', IS-1, NB, MB, -ONE,
- $ A( 1, IS ), LDA, RHS( 1 ), MB, ONE,
- $ C( 1, JS ), LDC )
- CALL DGEMM( 'N', 'N', IS-1, NB, MB, -ONE,
- $ D( 1, IS ), LDD, RHS( 1 ), MB, ONE,
- $ F( 1, JS ), LDF )
- END IF
- IF( J.LT.Q ) THEN
- K = MB*NB + 1
- CALL DGEMM( 'N', 'N', MB, N-JE, NB, ONE, RHS( K ),
- $ MB, B( JS, JE+1 ), LDB, ONE,
- $ C( IS, JE+1 ), LDC )
- CALL DGEMM( 'N', 'N', MB, N-JE, NB, ONE, RHS( K ),
- $ MB, E( JS, JE+1 ), LDE, ONE,
- $ F( IS, JE+1 ), LDF )
- END IF
-*
- END IF
-*
- 110 CONTINUE
- 120 CONTINUE
- ELSE
-*
-* Solve (I, J) - subsystem
-* A(I, I)' * R(I, J) + D(I, I)' * L(J, J) = C(I, J)
-* R(I, I) * B(J, J) + L(I, J) * E(J, J) = -F(I, J)
-* for I = 1, 2, ..., P, J = Q, Q - 1, ..., 1
-*
- SCALE = ONE
- SCALOC = ONE
- DO 200 I = 1, P
-*
- IS = IWORK( I )
- ISP1 = IS + 1
- IE = ( I+1 ) - 1
- MB = IE - IS + 1
- DO 190 J = Q, P + 2, -1
-*
- JS = IWORK( J )
- JSP1 = JS + 1
- JE = IWORK( J+1 ) - 1
- NB = JE - JS + 1
- ZDIM = MB*NB*2
- IF( ( MB.EQ.1 ) .AND. ( NB.EQ.1 ) ) THEN
-*
-* Build a 2-by-2 system Z' * x = RHS
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = -B( JS, JS )
- Z( 1, 2 ) = D( IS, IS )
- Z( 2, 2 ) = -E( JS, JS )
-*
-* Set up right hand side(s)
-*
- RHS( 1 ) = C( IS, JS )
- RHS( 2 ) = F( IS, JS )
-*
-* Solve Z' * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
-*
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV, SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 130 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 130 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
-*
-* Unpack solution vector(s)
-*
- C( IS, JS ) = RHS( 1 )
- F( IS, JS ) = RHS( 2 )
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( J.GT.P+2 ) THEN
- ALPHA = RHS( 1 )
- CALL DAXPY( JS-1, ALPHA, B( 1, JS ), 1, F( IS, 1 ),
- $ LDF )
- ALPHA = RHS( 2 )
- CALL DAXPY( JS-1, ALPHA, E( 1, JS ), 1, F( IS, 1 ),
- $ LDF )
- END IF
- IF( I.LT.P ) THEN
- ALPHA = -RHS( 1 )
- CALL DAXPY( M-IE, ALPHA, A( IS, IE+1 ), LDA,
- $ C( IE+1, JS ), 1 )
- ALPHA = -RHS( 2 )
- CALL DAXPY( M-IE, ALPHA, D( IS, IE+1 ), LDD,
- $ C( IE+1, JS ), 1 )
- END IF
-*
- ELSE IF( ( MB.EQ.1 ) .AND. ( NB.EQ.2 ) ) THEN
-*
-* Build a 4-by-4 system Z' * x = RHS
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = ZERO
- Z( 3, 1 ) = -B( JS, JS )
- Z( 4, 1 ) = -B( JSP1, JS )
-*
- Z( 1, 2 ) = ZERO
- Z( 2, 2 ) = A( IS, IS )
- Z( 3, 2 ) = -B( JS, JSP1 )
- Z( 4, 2 ) = -B( JSP1, JSP1 )
-*
- Z( 1, 3 ) = D( IS, IS )
- Z( 2, 3 ) = ZERO
- Z( 3, 3 ) = -E( JS, JS )
- Z( 4, 3 ) = ZERO
-*
- Z( 1, 4 ) = ZERO
- Z( 2, 4 ) = D( IS, IS )
- Z( 3, 4 ) = -E( JS, JSP1 )
- Z( 4, 4 ) = -E( JSP1, JSP1 )
-*
-* Set up right hand side(s)
-*
- RHS( 1 ) = C( IS, JS )
- RHS( 2 ) = C( IS, JSP1 )
- RHS( 3 ) = F( IS, JS )
- RHS( 4 ) = F( IS, JSP1 )
-*
-* Solve Z' * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV, SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 140 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 140 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
-*
-* Unpack solution vector(s)
-*
- C( IS, JS ) = RHS( 1 )
- C( IS, JSP1 ) = RHS( 2 )
- F( IS, JS ) = RHS( 3 )
- F( IS, JSP1 ) = RHS( 4 )
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( J.GT.P+2 ) THEN
- CALL DAXPY( JS-1, RHS( 1 ), B( 1, JS ), 1,
- $ F( IS, 1 ), LDF )
- CALL DAXPY( JS-1, RHS( 2 ), B( 1, JSP1 ), 1,
- $ F( IS, 1 ), LDF )
- CALL DAXPY( JS-1, RHS( 3 ), E( 1, JS ), 1,
- $ F( IS, 1 ), LDF )
- CALL DAXPY( JS-1, RHS( 4 ), E( 1, JSP1 ), 1,
- $ F( IS, 1 ), LDF )
- END IF
- IF( I.LT.P ) THEN
- CALL DGER( M-IE, NB, -ONE, A( IS, IE+1 ), LDA,
- $ RHS( 1 ), 1, C( IE+1, JS ), LDC )
- CALL DGER( M-IE, NB, -ONE, D( IS, IE+1 ), LDD,
- $ RHS( 3 ), 1, C( IE+1, JS ), LDC )
- END IF
-*
- ELSE IF( ( MB.EQ.2 ) .AND. ( NB.EQ.1 ) ) THEN
-*
-* Build a 4-by-4 system Z' * x = RHS
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = A( IS, ISP1 )
- Z( 3, 1 ) = -B( JS, JS )
- Z( 4, 1 ) = ZERO
-*
- Z( 1, 2 ) = A( ISP1, IS )
- Z( 2, 2 ) = A( ISP1, ISP1 )
- Z( 3, 2 ) = ZERO
- Z( 4, 2 ) = -B( JS, JS )
-*
- Z( 1, 3 ) = D( IS, IS )
- Z( 2, 3 ) = D( IS, ISP1 )
- Z( 3, 3 ) = -E( JS, JS )
- Z( 4, 3 ) = ZERO
-*
- Z( 1, 4 ) = ZERO
- Z( 2, 4 ) = D( ISP1, ISP1 )
- Z( 3, 4 ) = ZERO
- Z( 4, 4 ) = -E( JS, JS )
-*
-* Set up right hand side(s)
-*
- RHS( 1 ) = C( IS, JS )
- RHS( 2 ) = C( ISP1, JS )
- RHS( 3 ) = F( IS, JS )
- RHS( 4 ) = F( ISP1, JS )
-*
-* Solve Z' * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
-*
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV, SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 150 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 150 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
-*
-* Unpack solution vector(s)
-*
- C( IS, JS ) = RHS( 1 )
- C( ISP1, JS ) = RHS( 2 )
- F( IS, JS ) = RHS( 3 )
- F( ISP1, JS ) = RHS( 4 )
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( J.GT.P+2 ) THEN
- CALL DGER( MB, JS-1, ONE, RHS( 1 ), 1, B( 1, JS ),
- $ 1, F( IS, 1 ), LDF )
- CALL DGER( MB, JS-1, ONE, RHS( 3 ), 1, E( 1, JS ),
- $ 1, F( IS, 1 ), LDF )
- END IF
- IF( I.LT.P ) THEN
- CALL DGEMV( 'T', MB, M-IE, -ONE, A( IS, IE+1 ),
- $ LDA, RHS( 1 ), 1, ONE, C( IE+1, JS ),
- $ 1 )
- CALL DGEMV( 'T', MB, M-IE, -ONE, D( IS, IE+1 ),
- $ LDD, RHS( 3 ), 1, ONE, C( IE+1, JS ),
- $ 1 )
- END IF
-*
- ELSE IF( ( MB.EQ.2 ) .AND. ( NB.EQ.2 ) ) THEN
-*
-* Build an 8-by-8 system Z' * x = RHS
-*
- CALL DLASET( 'F', LDZ, LDZ, ZERO, ZERO, Z, LDZ )
-*
- Z( 1, 1 ) = A( IS, IS )
- Z( 2, 1 ) = A( IS, ISP1 )
- Z( 5, 1 ) = -B( JS, JS )
- Z( 7, 1 ) = -B( JSP1, JS )
-*
- Z( 1, 2 ) = A( ISP1, IS )
- Z( 2, 2 ) = A( ISP1, ISP1 )
- Z( 6, 2 ) = -B( JS, JS )
- Z( 8, 2 ) = -B( JSP1, JS )
-*
- Z( 3, 3 ) = A( IS, IS )
- Z( 4, 3 ) = A( IS, ISP1 )
- Z( 5, 3 ) = -B( JS, JSP1 )
- Z( 7, 3 ) = -B( JSP1, JSP1 )
-*
- Z( 3, 4 ) = A( ISP1, IS )
- Z( 4, 4 ) = A( ISP1, ISP1 )
- Z( 6, 4 ) = -B( JS, JSP1 )
- Z( 8, 4 ) = -B( JSP1, JSP1 )
-*
- Z( 1, 5 ) = D( IS, IS )
- Z( 2, 5 ) = D( IS, ISP1 )
- Z( 5, 5 ) = -E( JS, JS )
-*
- Z( 2, 6 ) = D( ISP1, ISP1 )
- Z( 6, 6 ) = -E( JS, JS )
-*
- Z( 3, 7 ) = D( IS, IS )
- Z( 4, 7 ) = D( IS, ISP1 )
- Z( 5, 7 ) = -E( JS, JSP1 )
- Z( 7, 7 ) = -E( JSP1, JSP1 )
-*
- Z( 4, 8 ) = D( ISP1, ISP1 )
- Z( 6, 8 ) = -E( JS, JSP1 )
- Z( 8, 8 ) = -E( JSP1, JSP1 )
-*
-* Set up right hand side(s)
-*
- K = 1
- II = MB*NB + 1
- DO 160 JJ = 0, NB - 1
- CALL DCOPY( MB, C( IS, JS+JJ ), 1, RHS( K ), 1 )
- CALL DCOPY( MB, F( IS, JS+JJ ), 1, RHS( II ), 1 )
- K = K + MB
- II = II + MB
- 160 CONTINUE
-*
-*
-* Solve Z' * x = RHS
-*
- CALL DGETC2( ZDIM, Z, LDZ, IPIV, JPIV, IERR )
- IF( IERR.GT.0 )
- $ INFO = IERR
-*
- CALL DGESC2( ZDIM, Z, LDZ, RHS, IPIV, JPIV, SCALOC )
- IF( SCALOC.NE.ONE ) THEN
- DO 170 K = 1, N
- CALL DSCAL( M, SCALOC, C( 1, K ), 1 )
- CALL DSCAL( M, SCALOC, F( 1, K ), 1 )
- 170 CONTINUE
- SCALE = SCALE*SCALOC
- END IF
-*
-* Unpack solution vector(s)
-*
- K = 1
- II = MB*NB + 1
- DO 180 JJ = 0, NB - 1
- CALL DCOPY( MB, RHS( K ), 1, C( IS, JS+JJ ), 1 )
- CALL DCOPY( MB, RHS( II ), 1, F( IS, JS+JJ ), 1 )
- K = K + MB
- II = II + MB
- 180 CONTINUE
-*
-* Substitute R(I, J) and L(I, J) into remaining
-* equation.
-*
- IF( J.GT.P+2 ) THEN
- CALL DGEMM( 'N', 'T', MB, JS-1, NB, ONE,
- $ C( IS, JS ), LDC, B( 1, JS ), LDB, ONE,
- $ F( IS, 1 ), LDF )
- CALL DGEMM( 'N', 'T', MB, JS-1, NB, ONE,
- $ F( IS, JS ), LDF, E( 1, JS ), LDE, ONE,
- $ F( IS, 1 ), LDF )
- END IF
- IF( I.LT.P ) THEN
- CALL DGEMM( 'T', 'N', M-IE, NB, MB, -ONE,
- $ A( IS, IE+1 ), LDA, C( IS, JS ), LDC,
- $ ONE, C( IE+1, JS ), LDC )
- CALL DGEMM( 'T', 'N', M-IE, NB, MB, -ONE,
- $ D( IS, IE+1 ), LDD, F( IS, JS ), LDF,
- $ ONE, C( IE+1, JS ), LDC )
- END IF
-*
- END IF
-*
- 190 CONTINUE
- 200 CONTINUE
-*
- END IF
- RETURN
-*
-* End of DTGSY2
-*
- END