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Diffstat (limited to '2.3-1/src/fortran/lapack/dtgex2.f')
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diff --git a/2.3-1/src/fortran/lapack/dtgex2.f b/2.3-1/src/fortran/lapack/dtgex2.f new file mode 100644 index 00000000..8351b7fd --- /dev/null +++ b/2.3-1/src/fortran/lapack/dtgex2.f @@ -0,0 +1,581 @@ + SUBROUTINE DTGEX2( WANTQ, WANTZ, N, A, LDA, B, LDB, Q, LDQ, Z, + $ LDZ, J1, N1, N2, WORK, LWORK, INFO ) +* +* -- LAPACK auxiliary routine (version 3.1) -- +* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. +* November 2006 +* +* .. Scalar Arguments .. + LOGICAL WANTQ, WANTZ + INTEGER INFO, J1, LDA, LDB, LDQ, LDZ, LWORK, N, N1, N2 +* .. +* .. Array Arguments .. + DOUBLE PRECISION A( LDA, * ), B( LDB, * ), Q( LDQ, * ), + $ WORK( * ), Z( LDZ, * ) +* .. +* +* Purpose +* ======= +* +* DTGEX2 swaps adjacent diagonal blocks (A11, B11) and (A22, B22) +* of size 1-by-1 or 2-by-2 in an upper (quasi) triangular matrix pair +* (A, B) by an orthogonal equivalence transformation. +* +* (A, B) must be in generalized real Schur canonical form (as returned +* by DGGES), i.e. A is block upper triangular with 1-by-1 and 2-by-2 +* diagonal blocks. B is upper triangular. +* +* Optionally, the matrices Q and Z of generalized Schur vectors are +* updated. +* +* Q(in) * A(in) * Z(in)' = Q(out) * A(out) * Z(out)' +* Q(in) * B(in) * Z(in)' = Q(out) * B(out) * Z(out)' +* +* +* Arguments +* ========= +* +* WANTQ (input) LOGICAL +* .TRUE. : update the left transformation matrix Q; +* .FALSE.: do not update Q. +* +* WANTZ (input) LOGICAL +* .TRUE. : update the right transformation matrix Z; +* .FALSE.: do not update Z. +* +* N (input) INTEGER +* The order of the matrices A and B. N >= 0. +* +* A (input/output) DOUBLE PRECISION arrays, dimensions (LDA,N) +* On entry, the matrix A in the pair (A, B). +* On exit, the updated matrix A. +* +* LDA (input) INTEGER +* The leading dimension of the array A. LDA >= max(1,N). +* +* B (input/output) DOUBLE PRECISION arrays, dimensions (LDB,N) +* On entry, the matrix B in the pair (A, B). +* On exit, the updated matrix B. +* +* LDB (input) INTEGER +* The leading dimension of the array B. LDB >= max(1,N). +* +* Q (input/output) DOUBLE PRECISION array, dimension (LDZ,N) +* On entry, if WANTQ = .TRUE., the orthogonal matrix Q. +* On exit, the updated matrix Q. +* Not referenced if WANTQ = .FALSE.. +* +* LDQ (input) INTEGER +* The leading dimension of the array Q. LDQ >= 1. +* If WANTQ = .TRUE., LDQ >= N. +* +* Z (input/output) DOUBLE PRECISION array, dimension (LDZ,N) +* On entry, if WANTZ =.TRUE., the orthogonal matrix Z. +* On exit, the updated matrix Z. +* Not referenced if WANTZ = .FALSE.. +* +* LDZ (input) INTEGER +* The leading dimension of the array Z. LDZ >= 1. +* If WANTZ = .TRUE., LDZ >= N. +* +* J1 (input) INTEGER +* The index to the first block (A11, B11). 1 <= J1 <= N. +* +* N1 (input) INTEGER +* The order of the first block (A11, B11). N1 = 0, 1 or 2. +* +* N2 (input) INTEGER +* The order of the second block (A22, B22). N2 = 0, 1 or 2. +* +* WORK (workspace) DOUBLE PRECISION array, dimension (MAX(1,LWORK)). +* +* LWORK (input) INTEGER +* The dimension of the array WORK. +* LWORK >= MAX( 1, N*(N2+N1), (N2+N1)*(N2+N1)*2 ) +* +* INFO (output) INTEGER +* =0: Successful exit +* >0: If INFO = 1, the transformed matrix (A, B) would be +* too far from generalized Schur form; the blocks are +* not swapped and (A, B) and (Q, Z) are unchanged. +* The problem of swapping is too ill-conditioned. +* <0: If INFO = -16: LWORK is too small. Appropriate value +* for LWORK is returned in WORK(1). +* +* Further Details +* =============== +* +* Based on contributions by +* Bo Kagstrom and Peter Poromaa, Department of Computing Science, +* Umea University, S-901 87 Umea, Sweden. +* +* In the current code both weak and strong stability tests are +* performed. The user can omit the strong stability test by changing +* the internal logical parameter WANDS to .FALSE.. See ref. [2] for +* details. +* +* [1] B. Kagstrom; A Direct Method for Reordering Eigenvalues in the +* Generalized Real Schur Form of a Regular Matrix Pair (A, B), in +* M.S. Moonen et al (eds), Linear Algebra for Large Scale and +* Real-Time Applications, Kluwer Academic Publ. 1993, pp 195-218. +* +* [2] B. Kagstrom and P. Poromaa; Computing Eigenspaces with Specified +* Eigenvalues of a Regular Matrix Pair (A, B) and Condition +* Estimation: Theory, Algorithms and Software, +* Report UMINF - 94.04, Department of Computing Science, Umea +* University, S-901 87 Umea, Sweden, 1994. Also as LAPACK Working +* Note 87. To appear in Numerical Algorithms, 1996. +* +* ===================================================================== +* Replaced various illegal calls to DCOPY by calls to DLASET, or by DO +* loops. Sven Hammarling, 1/5/02. +* +* .. Parameters .. + DOUBLE PRECISION ZERO, ONE + PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) + DOUBLE PRECISION TEN + PARAMETER ( TEN = 1.0D+01 ) + INTEGER LDST + PARAMETER ( LDST = 4 ) + LOGICAL WANDS + PARAMETER ( WANDS = .TRUE. ) +* .. +* .. Local Scalars .. + LOGICAL DTRONG, WEAK + INTEGER I, IDUM, LINFO, M + DOUBLE PRECISION BQRA21, BRQA21, DDUM, DNORM, DSCALE, DSUM, EPS, + $ F, G, SA, SB, SCALE, SMLNUM, SS, THRESH, WS +* .. +* .. Local Arrays .. + INTEGER IWORK( LDST ) + DOUBLE PRECISION AI( 2 ), AR( 2 ), BE( 2 ), IR( LDST, LDST ), + $ IRCOP( LDST, LDST ), LI( LDST, LDST ), + $ LICOP( LDST, LDST ), S( LDST, LDST ), + $ SCPY( LDST, LDST ), T( LDST, LDST ), + $ TAUL( LDST ), TAUR( LDST ), TCPY( LDST, LDST ) +* .. +* .. External Functions .. + DOUBLE PRECISION DLAMCH + EXTERNAL DLAMCH +* .. +* .. External Subroutines .. + EXTERNAL DGEMM, DGEQR2, DGERQ2, DLACPY, DLAGV2, DLARTG, + $ DLASET, DLASSQ, DORG2R, DORGR2, DORM2R, DORMR2, + $ DROT, DSCAL, DTGSY2 +* .. +* .. Intrinsic Functions .. + INTRINSIC ABS, MAX, SQRT +* .. +* .. Executable Statements .. +* + INFO = 0 +* +* Quick return if possible +* + IF( N.LE.1 .OR. N1.LE.0 .OR. N2.LE.0 ) + $ RETURN + IF( N1.GT.N .OR. ( J1+N1 ).GT.N ) + $ RETURN + M = N1 + N2 + IF( LWORK.LT.MAX( 1, N*M, M*M*2 ) ) THEN + INFO = -16 + WORK( 1 ) = MAX( 1, N*M, M*M*2 ) + RETURN + END IF +* + WEAK = .FALSE. + DTRONG = .FALSE. +* +* Make a local copy of selected block +* + CALL DLASET( 'Full', LDST, LDST, ZERO, ZERO, LI, LDST ) + CALL DLASET( 'Full', LDST, LDST, ZERO, ZERO, IR, LDST ) + CALL DLACPY( 'Full', M, M, A( J1, J1 ), LDA, S, LDST ) + CALL DLACPY( 'Full', M, M, B( J1, J1 ), LDB, T, LDST ) +* +* Compute threshold for testing acceptance of swapping. +* + EPS = DLAMCH( 'P' ) + SMLNUM = DLAMCH( 'S' ) / EPS + DSCALE = ZERO + DSUM = ONE + CALL DLACPY( 'Full', M, M, S, LDST, WORK, M ) + CALL DLASSQ( M*M, WORK, 1, DSCALE, DSUM ) + CALL DLACPY( 'Full', M, M, T, LDST, WORK, M ) + CALL DLASSQ( M*M, WORK, 1, DSCALE, DSUM ) + DNORM = DSCALE*SQRT( DSUM ) + THRESH = MAX( TEN*EPS*DNORM, SMLNUM ) +* + IF( M.EQ.2 ) THEN +* +* CASE 1: Swap 1-by-1 and 1-by-1 blocks. +* +* Compute orthogonal QL and RQ that swap 1-by-1 and 1-by-1 blocks +* using Givens rotations and perform the swap tentatively. +* + F = S( 2, 2 )*T( 1, 1 ) - T( 2, 2 )*S( 1, 1 ) + G = S( 2, 2 )*T( 1, 2 ) - T( 2, 2 )*S( 1, 2 ) + SB = ABS( T( 2, 2 ) ) + SA = ABS( S( 2, 2 ) ) + CALL DLARTG( F, G, IR( 1, 2 ), IR( 1, 1 ), DDUM ) + IR( 2, 1 ) = -IR( 1, 2 ) + IR( 2, 2 ) = IR( 1, 1 ) + CALL DROT( 2, S( 1, 1 ), 1, S( 1, 2 ), 1, IR( 1, 1 ), + $ IR( 2, 1 ) ) + CALL DROT( 2, T( 1, 1 ), 1, T( 1, 2 ), 1, IR( 1, 1 ), + $ IR( 2, 1 ) ) + IF( SA.GE.SB ) THEN + CALL DLARTG( S( 1, 1 ), S( 2, 1 ), LI( 1, 1 ), LI( 2, 1 ), + $ DDUM ) + ELSE + CALL DLARTG( T( 1, 1 ), T( 2, 1 ), LI( 1, 1 ), LI( 2, 1 ), + $ DDUM ) + END IF + CALL DROT( 2, S( 1, 1 ), LDST, S( 2, 1 ), LDST, LI( 1, 1 ), + $ LI( 2, 1 ) ) + CALL DROT( 2, T( 1, 1 ), LDST, T( 2, 1 ), LDST, LI( 1, 1 ), + $ LI( 2, 1 ) ) + LI( 2, 2 ) = LI( 1, 1 ) + LI( 1, 2 ) = -LI( 2, 1 ) +* +* Weak stability test: +* |S21| + |T21| <= O(EPS * F-norm((S, T))) +* + WS = ABS( S( 2, 1 ) ) + ABS( T( 2, 1 ) ) + WEAK = WS.LE.THRESH + IF( .NOT.WEAK ) + $ GO TO 70 +* + IF( WANDS ) THEN +* +* Strong stability test: +* F-norm((A-QL'*S*QR, B-QL'*T*QR)) <= O(EPS*F-norm((A,B))) +* + CALL DLACPY( 'Full', M, M, A( J1, J1 ), LDA, WORK( M*M+1 ), + $ M ) + CALL DGEMM( 'N', 'N', M, M, M, ONE, LI, LDST, S, LDST, ZERO, + $ WORK, M ) + CALL DGEMM( 'N', 'T', M, M, M, -ONE, WORK, M, IR, LDST, ONE, + $ WORK( M*M+1 ), M ) + DSCALE = ZERO + DSUM = ONE + CALL DLASSQ( M*M, WORK( M*M+1 ), 1, DSCALE, DSUM ) +* + CALL DLACPY( 'Full', M, M, B( J1, J1 ), LDB, WORK( M*M+1 ), + $ M ) + CALL DGEMM( 'N', 'N', M, M, M, ONE, LI, LDST, T, LDST, ZERO, + $ WORK, M ) + CALL DGEMM( 'N', 'T', M, M, M, -ONE, WORK, M, IR, LDST, ONE, + $ WORK( M*M+1 ), M ) + CALL DLASSQ( M*M, WORK( M*M+1 ), 1, DSCALE, DSUM ) + SS = DSCALE*SQRT( DSUM ) + DTRONG = SS.LE.THRESH + IF( .NOT.DTRONG ) + $ GO TO 70 + END IF +* +* Update (A(J1:J1+M-1, M+J1:N), B(J1:J1+M-1, M+J1:N)) and +* (A(1:J1-1, J1:J1+M), B(1:J1-1, J1:J1+M)). +* + CALL DROT( J1+1, A( 1, J1 ), 1, A( 1, J1+1 ), 1, IR( 1, 1 ), + $ IR( 2, 1 ) ) + CALL DROT( J1+1, B( 1, J1 ), 1, B( 1, J1+1 ), 1, IR( 1, 1 ), + $ IR( 2, 1 ) ) + CALL DROT( N-J1+1, A( J1, J1 ), LDA, A( J1+1, J1 ), LDA, + $ LI( 1, 1 ), LI( 2, 1 ) ) + CALL DROT( N-J1+1, B( J1, J1 ), LDB, B( J1+1, J1 ), LDB, + $ LI( 1, 1 ), LI( 2, 1 ) ) +* +* Set N1-by-N2 (2,1) - blocks to ZERO. +* + A( J1+1, J1 ) = ZERO + B( J1+1, J1 ) = ZERO +* +* Accumulate transformations into Q and Z if requested. +* + IF( WANTZ ) + $ CALL DROT( N, Z( 1, J1 ), 1, Z( 1, J1+1 ), 1, IR( 1, 1 ), + $ IR( 2, 1 ) ) + IF( WANTQ ) + $ CALL DROT( N, Q( 1, J1 ), 1, Q( 1, J1+1 ), 1, LI( 1, 1 ), + $ LI( 2, 1 ) ) +* +* Exit with INFO = 0 if swap was successfully performed. +* + RETURN +* + ELSE +* +* CASE 2: Swap 1-by-1 and 2-by-2 blocks, or 2-by-2 +* and 2-by-2 blocks. +* +* Solve the generalized Sylvester equation +* S11 * R - L * S22 = SCALE * S12 +* T11 * R - L * T22 = SCALE * T12 +* for R and L. Solutions in LI and IR. +* + CALL DLACPY( 'Full', N1, N2, T( 1, N1+1 ), LDST, LI, LDST ) + CALL DLACPY( 'Full', N1, N2, S( 1, N1+1 ), LDST, + $ IR( N2+1, N1+1 ), LDST ) + CALL DTGSY2( 'N', 0, N1, N2, S, LDST, S( N1+1, N1+1 ), LDST, + $ IR( N2+1, N1+1 ), LDST, T, LDST, T( N1+1, N1+1 ), + $ LDST, LI, LDST, SCALE, DSUM, DSCALE, IWORK, IDUM, + $ LINFO ) +* +* Compute orthogonal matrix QL: +* +* QL' * LI = [ TL ] +* [ 0 ] +* where +* LI = [ -L ] +* [ SCALE * identity(N2) ] +* + DO 10 I = 1, N2 + CALL DSCAL( N1, -ONE, LI( 1, I ), 1 ) + LI( N1+I, I ) = SCALE + 10 CONTINUE + CALL DGEQR2( M, N2, LI, LDST, TAUL, WORK, LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 + CALL DORG2R( M, M, N2, LI, LDST, TAUL, WORK, LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 +* +* Compute orthogonal matrix RQ: +* +* IR * RQ' = [ 0 TR], +* +* where IR = [ SCALE * identity(N1), R ] +* + DO 20 I = 1, N1 + IR( N2+I, I ) = SCALE + 20 CONTINUE + CALL DGERQ2( N1, M, IR( N2+1, 1 ), LDST, TAUR, WORK, LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 + CALL DORGR2( M, M, N1, IR, LDST, TAUR, WORK, LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 +* +* Perform the swapping tentatively: +* + CALL DGEMM( 'T', 'N', M, M, M, ONE, LI, LDST, S, LDST, ZERO, + $ WORK, M ) + CALL DGEMM( 'N', 'T', M, M, M, ONE, WORK, M, IR, LDST, ZERO, S, + $ LDST ) + CALL DGEMM( 'T', 'N', M, M, M, ONE, LI, LDST, T, LDST, ZERO, + $ WORK, M ) + CALL DGEMM( 'N', 'T', M, M, M, ONE, WORK, M, IR, LDST, ZERO, T, + $ LDST ) + CALL DLACPY( 'F', M, M, S, LDST, SCPY, LDST ) + CALL DLACPY( 'F', M, M, T, LDST, TCPY, LDST ) + CALL DLACPY( 'F', M, M, IR, LDST, IRCOP, LDST ) + CALL DLACPY( 'F', M, M, LI, LDST, LICOP, LDST ) +* +* Triangularize the B-part by an RQ factorization. +* Apply transformation (from left) to A-part, giving S. +* + CALL DGERQ2( M, M, T, LDST, TAUR, WORK, LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 + CALL DORMR2( 'R', 'T', M, M, M, T, LDST, TAUR, S, LDST, WORK, + $ LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 + CALL DORMR2( 'L', 'N', M, M, M, T, LDST, TAUR, IR, LDST, WORK, + $ LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 +* +* Compute F-norm(S21) in BRQA21. (T21 is 0.) +* + DSCALE = ZERO + DSUM = ONE + DO 30 I = 1, N2 + CALL DLASSQ( N1, S( N2+1, I ), 1, DSCALE, DSUM ) + 30 CONTINUE + BRQA21 = DSCALE*SQRT( DSUM ) +* +* Triangularize the B-part by a QR factorization. +* Apply transformation (from right) to A-part, giving S. +* + CALL DGEQR2( M, M, TCPY, LDST, TAUL, WORK, LINFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 + CALL DORM2R( 'L', 'T', M, M, M, TCPY, LDST, TAUL, SCPY, LDST, + $ WORK, INFO ) + CALL DORM2R( 'R', 'N', M, M, M, TCPY, LDST, TAUL, LICOP, LDST, + $ WORK, INFO ) + IF( LINFO.NE.0 ) + $ GO TO 70 +* +* Compute F-norm(S21) in BQRA21. (T21 is 0.) +* + DSCALE = ZERO + DSUM = ONE + DO 40 I = 1, N2 + CALL DLASSQ( N1, SCPY( N2+1, I ), 1, DSCALE, DSUM ) + 40 CONTINUE + BQRA21 = DSCALE*SQRT( DSUM ) +* +* Decide which method to use. +* Weak stability test: +* F-norm(S21) <= O(EPS * F-norm((S, T))) +* + IF( BQRA21.LE.BRQA21 .AND. BQRA21.LE.THRESH ) THEN + CALL DLACPY( 'F', M, M, SCPY, LDST, S, LDST ) + CALL DLACPY( 'F', M, M, TCPY, LDST, T, LDST ) + CALL DLACPY( 'F', M, M, IRCOP, LDST, IR, LDST ) + CALL DLACPY( 'F', M, M, LICOP, LDST, LI, LDST ) + ELSE IF( BRQA21.GE.THRESH ) THEN + GO TO 70 + END IF +* +* Set lower triangle of B-part to zero +* + CALL DLASET( 'Lower', M-1, M-1, ZERO, ZERO, T(2,1), LDST ) +* + IF( WANDS ) THEN +* +* Strong stability test: +* F-norm((A-QL*S*QR', B-QL*T*QR')) <= O(EPS*F-norm((A,B))) +* + CALL DLACPY( 'Full', M, M, A( J1, J1 ), LDA, WORK( M*M+1 ), + $ M ) + CALL DGEMM( 'N', 'N', M, M, M, ONE, LI, LDST, S, LDST, ZERO, + $ WORK, M ) + CALL DGEMM( 'N', 'N', M, M, M, -ONE, WORK, M, IR, LDST, ONE, + $ WORK( M*M+1 ), M ) + DSCALE = ZERO + DSUM = ONE + CALL DLASSQ( M*M, WORK( M*M+1 ), 1, DSCALE, DSUM ) +* + CALL DLACPY( 'Full', M, M, B( J1, J1 ), LDB, WORK( M*M+1 ), + $ M ) + CALL DGEMM( 'N', 'N', M, M, M, ONE, LI, LDST, T, LDST, ZERO, + $ WORK, M ) + CALL DGEMM( 'N', 'N', M, M, M, -ONE, WORK, M, IR, LDST, ONE, + $ WORK( M*M+1 ), M ) + CALL DLASSQ( M*M, WORK( M*M+1 ), 1, DSCALE, DSUM ) + SS = DSCALE*SQRT( DSUM ) + DTRONG = ( SS.LE.THRESH ) + IF( .NOT.DTRONG ) + $ GO TO 70 +* + END IF +* +* If the swap is accepted ("weakly" and "strongly"), apply the +* transformations and set N1-by-N2 (2,1)-block to zero. +* + CALL DLASET( 'Full', N1, N2, ZERO, ZERO, S(N2+1,1), LDST ) +* +* copy back M-by-M diagonal block starting at index J1 of (A, B) +* + CALL DLACPY( 'F', M, M, S, LDST, A( J1, J1 ), LDA ) + CALL DLACPY( 'F', M, M, T, LDST, B( J1, J1 ), LDB ) + CALL DLASET( 'Full', LDST, LDST, ZERO, ZERO, T, LDST ) +* +* Standardize existing 2-by-2 blocks. +* + DO 50 I = 1, M*M + WORK(I) = ZERO + 50 CONTINUE + WORK( 1 ) = ONE + T( 1, 1 ) = ONE + IDUM = LWORK - M*M - 2 + IF( N2.GT.1 ) THEN + CALL DLAGV2( A( J1, J1 ), LDA, B( J1, J1 ), LDB, AR, AI, BE, + $ WORK( 1 ), WORK( 2 ), T( 1, 1 ), T( 2, 1 ) ) + WORK( M+1 ) = -WORK( 2 ) + WORK( M+2 ) = WORK( 1 ) + T( N2, N2 ) = T( 1, 1 ) + T( 1, 2 ) = -T( 2, 1 ) + END IF + WORK( M*M ) = ONE + T( M, M ) = ONE +* + IF( N1.GT.1 ) THEN + CALL DLAGV2( A( J1+N2, J1+N2 ), LDA, B( J1+N2, J1+N2 ), LDB, + $ TAUR, TAUL, WORK( M*M+1 ), WORK( N2*M+N2+1 ), + $ WORK( N2*M+N2+2 ), T( N2+1, N2+1 ), + $ T( M, M-1 ) ) + WORK( M*M ) = WORK( N2*M+N2+1 ) + WORK( M*M-1 ) = -WORK( N2*M+N2+2 ) + T( M, M ) = T( N2+1, N2+1 ) + T( M-1, M ) = -T( M, M-1 ) + END IF + CALL DGEMM( 'T', 'N', N2, N1, N2, ONE, WORK, M, A( J1, J1+N2 ), + $ LDA, ZERO, WORK( M*M+1 ), N2 ) + CALL DLACPY( 'Full', N2, N1, WORK( M*M+1 ), N2, A( J1, J1+N2 ), + $ LDA ) + CALL DGEMM( 'T', 'N', N2, N1, N2, ONE, WORK, M, B( J1, J1+N2 ), + $ LDB, ZERO, WORK( M*M+1 ), N2 ) + CALL DLACPY( 'Full', N2, N1, WORK( M*M+1 ), N2, B( J1, J1+N2 ), + $ LDB ) + CALL DGEMM( 'N', 'N', M, M, M, ONE, LI, LDST, WORK, M, ZERO, + $ WORK( M*M+1 ), M ) + CALL DLACPY( 'Full', M, M, WORK( M*M+1 ), M, LI, LDST ) + CALL DGEMM( 'N', 'N', N2, N1, N1, ONE, A( J1, J1+N2 ), LDA, + $ T( N2+1, N2+1 ), LDST, ZERO, WORK, N2 ) + CALL DLACPY( 'Full', N2, N1, WORK, N2, A( J1, J1+N2 ), LDA ) + CALL DGEMM( 'N', 'N', N2, N1, N1, ONE, B( J1, J1+N2 ), LDB, + $ T( N2+1, N2+1 ), LDST, ZERO, WORK, N2 ) + CALL DLACPY( 'Full', N2, N1, WORK, N2, B( J1, J1+N2 ), LDB ) + CALL DGEMM( 'T', 'N', M, M, M, ONE, IR, LDST, T, LDST, ZERO, + $ WORK, M ) + CALL DLACPY( 'Full', M, M, WORK, M, IR, LDST ) +* +* Accumulate transformations into Q and Z if requested. +* + IF( WANTQ ) THEN + CALL DGEMM( 'N', 'N', N, M, M, ONE, Q( 1, J1 ), LDQ, LI, + $ LDST, ZERO, WORK, N ) + CALL DLACPY( 'Full', N, M, WORK, N, Q( 1, J1 ), LDQ ) +* + END IF +* + IF( WANTZ ) THEN + CALL DGEMM( 'N', 'N', N, M, M, ONE, Z( 1, J1 ), LDZ, IR, + $ LDST, ZERO, WORK, N ) + CALL DLACPY( 'Full', N, M, WORK, N, Z( 1, J1 ), LDZ ) +* + END IF +* +* Update (A(J1:J1+M-1, M+J1:N), B(J1:J1+M-1, M+J1:N)) and +* (A(1:J1-1, J1:J1+M), B(1:J1-1, J1:J1+M)). +* + I = J1 + M + IF( I.LE.N ) THEN + CALL DGEMM( 'T', 'N', M, N-I+1, M, ONE, LI, LDST, + $ A( J1, I ), LDA, ZERO, WORK, M ) + CALL DLACPY( 'Full', M, N-I+1, WORK, M, A( J1, I ), LDA ) + CALL DGEMM( 'T', 'N', M, N-I+1, M, ONE, LI, LDST, + $ B( J1, I ), LDA, ZERO, WORK, M ) + CALL DLACPY( 'Full', M, N-I+1, WORK, M, B( J1, I ), LDB ) + END IF + I = J1 - 1 + IF( I.GT.0 ) THEN + CALL DGEMM( 'N', 'N', I, M, M, ONE, A( 1, J1 ), LDA, IR, + $ LDST, ZERO, WORK, I ) + CALL DLACPY( 'Full', I, M, WORK, I, A( 1, J1 ), LDA ) + CALL DGEMM( 'N', 'N', I, M, M, ONE, B( 1, J1 ), LDB, IR, + $ LDST, ZERO, WORK, I ) + CALL DLACPY( 'Full', I, M, WORK, I, B( 1, J1 ), LDB ) + END IF +* +* Exit with INFO = 0 if swap was successfully performed. +* + RETURN +* + END IF +* +* Exit with INFO = 1 if swap was rejected. +* + 70 CONTINUE +* + INFO = 1 + RETURN +* +* End of DTGEX2 +* + END |