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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/dlaqr5.f | |
parent | 9f652ffc16a310ac6641a9766c5b9e2671e0e9cb (diff) | |
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Moving lapack to right place
Diffstat (limited to 'src/lib/lapack/dlaqr5.f')
-rw-r--r-- | src/lib/lapack/dlaqr5.f | 812 |
1 files changed, 0 insertions, 812 deletions
diff --git a/src/lib/lapack/dlaqr5.f b/src/lib/lapack/dlaqr5.f deleted file mode 100644 index 17857572..00000000 --- a/src/lib/lapack/dlaqr5.f +++ /dev/null @@ -1,812 +0,0 @@ - SUBROUTINE DLAQR5( WANTT, WANTZ, KACC22, N, KTOP, KBOT, NSHFTS, - $ SR, SI, H, LDH, ILOZ, IHIZ, Z, LDZ, V, LDV, U, - $ LDU, NV, WV, LDWV, NH, WH, LDWH ) -* -* -- LAPACK auxiliary routine (version 3.1) -- -* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. -* November 2006 -* -* .. Scalar Arguments .. - INTEGER IHIZ, ILOZ, KACC22, KBOT, KTOP, LDH, LDU, LDV, - $ LDWH, LDWV, LDZ, N, NH, NSHFTS, NV - LOGICAL WANTT, WANTZ -* .. -* .. Array Arguments .. - DOUBLE PRECISION H( LDH, * ), SI( * ), SR( * ), U( LDU, * ), - $ V( LDV, * ), WH( LDWH, * ), WV( LDWV, * ), - $ Z( LDZ, * ) -* .. -* -* This auxiliary subroutine called by DLAQR0 performs a -* single small-bulge multi-shift QR sweep. -* -* WANTT (input) logical scalar -* WANTT = .true. if the quasi-triangular Schur factor -* is being computed. WANTT is set to .false. otherwise. -* -* WANTZ (input) logical scalar -* WANTZ = .true. if the orthogonal Schur factor is being -* computed. WANTZ is set to .false. otherwise. -* -* KACC22 (input) integer with value 0, 1, or 2. -* Specifies the computation mode of far-from-diagonal -* orthogonal updates. -* = 0: DLAQR5 does not accumulate reflections and does not -* use matrix-matrix multiply to update far-from-diagonal -* matrix entries. -* = 1: DLAQR5 accumulates reflections and uses matrix-matrix -* multiply to update the far-from-diagonal matrix entries. -* = 2: DLAQR5 accumulates reflections, uses matrix-matrix -* multiply to update the far-from-diagonal matrix entries, -* and takes advantage of 2-by-2 block structure during -* matrix multiplies. -* -* N (input) integer scalar -* N is the order of the Hessenberg matrix H upon which this -* subroutine operates. -* -* KTOP (input) integer scalar -* KBOT (input) integer scalar -* These are the first and last rows and columns of an -* isolated diagonal block upon which the QR sweep is to be -* applied. It is assumed without a check that -* either KTOP = 1 or H(KTOP,KTOP-1) = 0 -* and -* either KBOT = N or H(KBOT+1,KBOT) = 0. -* -* NSHFTS (input) integer scalar -* NSHFTS gives the number of simultaneous shifts. NSHFTS -* must be positive and even. -* -* SR (input) DOUBLE PRECISION array of size (NSHFTS) -* SI (input) DOUBLE PRECISION array of size (NSHFTS) -* SR contains the real parts and SI contains the imaginary -* parts of the NSHFTS shifts of origin that define the -* multi-shift QR sweep. -* -* H (input/output) DOUBLE PRECISION array of size (LDH,N) -* On input H contains a Hessenberg matrix. On output a -* multi-shift QR sweep with shifts SR(J)+i*SI(J) is applied -* to the isolated diagonal block in rows and columns KTOP -* through KBOT. -* -* LDH (input) integer scalar -* LDH is the leading dimension of H just as declared in the -* calling procedure. LDH.GE.MAX(1,N). -* -* ILOZ (input) INTEGER -* IHIZ (input) INTEGER -* Specify the rows of Z to which transformations must be -* applied if WANTZ is .TRUE.. 1 .LE. ILOZ .LE. IHIZ .LE. N -* -* Z (input/output) DOUBLE PRECISION array of size (LDZ,IHI) -* If WANTZ = .TRUE., then the QR Sweep orthogonal -* similarity transformation is accumulated into -* Z(ILOZ:IHIZ,ILO:IHI) from the right. -* If WANTZ = .FALSE., then Z is unreferenced. -* -* LDZ (input) integer scalar -* LDA is the leading dimension of Z just as declared in -* the calling procedure. LDZ.GE.N. -* -* V (workspace) DOUBLE PRECISION array of size (LDV,NSHFTS/2) -* -* LDV (input) integer scalar -* LDV is the leading dimension of V as declared in the -* calling procedure. LDV.GE.3. -* -* U (workspace) DOUBLE PRECISION array of size -* (LDU,3*NSHFTS-3) -* -* LDU (input) integer scalar -* LDU is the leading dimension of U just as declared in the -* in the calling subroutine. LDU.GE.3*NSHFTS-3. -* -* NH (input) integer scalar -* NH is the number of columns in array WH available for -* workspace. NH.GE.1. -* -* WH (workspace) DOUBLE PRECISION array of size (LDWH,NH) -* -* LDWH (input) integer scalar -* Leading dimension of WH just as declared in the -* calling procedure. LDWH.GE.3*NSHFTS-3. -* -* NV (input) integer scalar -* NV is the number of rows in WV agailable for workspace. -* NV.GE.1. -* -* WV (workspace) DOUBLE PRECISION array of size -* (LDWV,3*NSHFTS-3) -* -* LDWV (input) integer scalar -* LDWV is the leading dimension of WV as declared in the -* in the calling subroutine. LDWV.GE.NV. -* -* -* ================================================================ -* Based on contributions by -* Karen Braman and Ralph Byers, Department of Mathematics, -* University of Kansas, USA -* -* ============================================================ -* Reference: -* -* K. Braman, R. Byers and R. Mathias, The Multi-Shift QR -* Algorithm Part I: Maintaining Well Focused Shifts, and -* Level 3 Performance, SIAM Journal of Matrix Analysis, -* volume 23, pages 929--947, 2002. -* -* ============================================================ -* .. Parameters .. - DOUBLE PRECISION ZERO, ONE - PARAMETER ( ZERO = 0.0d0, ONE = 1.0d0 ) -* .. -* .. Local Scalars .. - DOUBLE PRECISION ALPHA, BETA, H11, H12, H21, H22, REFSUM, - $ SAFMAX, SAFMIN, SCL, SMLNUM, SWAP, TST1, TST2, - $ ULP - INTEGER I, I2, I4, INCOL, J, J2, J4, JBOT, JCOL, JLEN, - $ JROW, JTOP, K, K1, KDU, KMS, KNZ, KRCOL, KZS, - $ M, M22, MBOT, MEND, MSTART, MTOP, NBMPS, NDCOL, - $ NS, NU - LOGICAL ACCUM, BLK22, BMP22 -* .. -* .. External Functions .. - DOUBLE PRECISION DLAMCH - EXTERNAL DLAMCH -* .. -* .. Intrinsic Functions .. -* - INTRINSIC ABS, DBLE, MAX, MIN, MOD -* .. -* .. Local Arrays .. - DOUBLE PRECISION VT( 3 ) -* .. -* .. External Subroutines .. - EXTERNAL DGEMM, DLABAD, DLACPY, DLAQR1, DLARFG, DLASET, - $ DTRMM -* .. -* .. Executable Statements .. -* -* ==== If there are no shifts, then there is nothing to do. ==== -* - IF( NSHFTS.LT.2 ) - $ RETURN -* -* ==== If the active block is empty or 1-by-1, then there -* . is nothing to do. ==== -* - IF( KTOP.GE.KBOT ) - $ RETURN -* -* ==== Shuffle shifts into pairs of real shifts and pairs -* . of complex conjugate shifts assuming complex -* . conjugate shifts are already adjacent to one -* . another. ==== -* - DO 10 I = 1, NSHFTS - 2, 2 - IF( SI( I ).NE.-SI( I+1 ) ) THEN -* - SWAP = SR( I ) - SR( I ) = SR( I+1 ) - SR( I+1 ) = SR( I+2 ) - SR( I+2 ) = SWAP -* - SWAP = SI( I ) - SI( I ) = SI( I+1 ) - SI( I+1 ) = SI( I+2 ) - SI( I+2 ) = SWAP - END IF - 10 CONTINUE -* -* ==== NSHFTS is supposed to be even, but if is odd, -* . then simply reduce it by one. The shuffle above -* . ensures that the dropped shift is real and that -* . the remaining shifts are paired. ==== -* - NS = NSHFTS - MOD( NSHFTS, 2 ) -* -* ==== Machine constants for deflation ==== -* - SAFMIN = DLAMCH( 'SAFE MINIMUM' ) - SAFMAX = ONE / SAFMIN - CALL DLABAD( SAFMIN, SAFMAX ) - ULP = DLAMCH( 'PRECISION' ) - SMLNUM = SAFMIN*( DBLE( N ) / ULP ) -* -* ==== Use accumulated reflections to update far-from-diagonal -* . entries ? ==== -* - ACCUM = ( KACC22.EQ.1 ) .OR. ( KACC22.EQ.2 ) -* -* ==== If so, exploit the 2-by-2 block structure? ==== -* - BLK22 = ( NS.GT.2 ) .AND. ( KACC22.EQ.2 ) -* -* ==== clear trash ==== -* - IF( KTOP+2.LE.KBOT ) - $ H( KTOP+2, KTOP ) = ZERO -* -* ==== NBMPS = number of 2-shift bulges in the chain ==== -* - NBMPS = NS / 2 -* -* ==== KDU = width of slab ==== -* - KDU = 6*NBMPS - 3 -* -* ==== Create and chase chains of NBMPS bulges ==== -* - DO 220 INCOL = 3*( 1-NBMPS ) + KTOP - 1, KBOT - 2, 3*NBMPS - 2 - NDCOL = INCOL + KDU - IF( ACCUM ) - $ CALL DLASET( 'ALL', KDU, KDU, ZERO, ONE, U, LDU ) -* -* ==== Near-the-diagonal bulge chase. The following loop -* . performs the near-the-diagonal part of a small bulge -* . multi-shift QR sweep. Each 6*NBMPS-2 column diagonal -* . chunk extends from column INCOL to column NDCOL -* . (including both column INCOL and column NDCOL). The -* . following loop chases a 3*NBMPS column long chain of -* . NBMPS bulges 3*NBMPS-2 columns to the right. (INCOL -* . may be less than KTOP and and NDCOL may be greater than -* . KBOT indicating phantom columns from which to chase -* . bulges before they are actually introduced or to which -* . to chase bulges beyond column KBOT.) ==== -* - DO 150 KRCOL = INCOL, MIN( INCOL+3*NBMPS-3, KBOT-2 ) -* -* ==== Bulges number MTOP to MBOT are active double implicit -* . shift bulges. There may or may not also be small -* . 2-by-2 bulge, if there is room. The inactive bulges -* . (if any) must wait until the active bulges have moved -* . down the diagonal to make room. The phantom matrix -* . paradigm described above helps keep track. ==== -* - MTOP = MAX( 1, ( ( KTOP-1 )-KRCOL+2 ) / 3+1 ) - MBOT = MIN( NBMPS, ( KBOT-KRCOL ) / 3 ) - M22 = MBOT + 1 - BMP22 = ( MBOT.LT.NBMPS ) .AND. ( KRCOL+3*( M22-1 ) ).EQ. - $ ( KBOT-2 ) -* -* ==== Generate reflections to chase the chain right -* . one column. (The minimum value of K is KTOP-1.) ==== -* - DO 20 M = MTOP, MBOT - K = KRCOL + 3*( M-1 ) - IF( K.EQ.KTOP-1 ) THEN - CALL DLAQR1( 3, H( KTOP, KTOP ), LDH, SR( 2*M-1 ), - $ SI( 2*M-1 ), SR( 2*M ), SI( 2*M ), - $ V( 1, M ) ) - ALPHA = V( 1, M ) - CALL DLARFG( 3, ALPHA, V( 2, M ), 1, V( 1, M ) ) - ELSE - BETA = H( K+1, K ) - V( 2, M ) = H( K+2, K ) - V( 3, M ) = H( K+3, K ) - CALL DLARFG( 3, BETA, V( 2, M ), 1, V( 1, M ) ) -* -* ==== A Bulge may collapse because of vigilant -* . deflation or destructive underflow. (The -* . initial bulge is always collapsed.) Use -* . the two-small-subdiagonals trick to try -* . to get it started again. If V(2,M).NE.0 and -* . V(3,M) = H(K+3,K+1) = H(K+3,K+2) = 0, then -* . this bulge is collapsing into a zero -* . subdiagonal. It will be restarted next -* . trip through the loop.) -* - IF( V( 1, M ).NE.ZERO .AND. - $ ( V( 3, M ).NE.ZERO .OR. ( H( K+3, - $ K+1 ).EQ.ZERO .AND. H( K+3, K+2 ).EQ.ZERO ) ) ) - $ THEN -* -* ==== Typical case: not collapsed (yet). ==== -* - H( K+1, K ) = BETA - H( K+2, K ) = ZERO - H( K+3, K ) = ZERO - ELSE -* -* ==== Atypical case: collapsed. Attempt to -* . reintroduce ignoring H(K+1,K). If the -* . fill resulting from the new reflector -* . is too large, then abandon it. -* . Otherwise, use the new one. ==== -* - CALL DLAQR1( 3, H( K+1, K+1 ), LDH, SR( 2*M-1 ), - $ SI( 2*M-1 ), SR( 2*M ), SI( 2*M ), - $ VT ) - SCL = ABS( VT( 1 ) ) + ABS( VT( 2 ) ) + - $ ABS( VT( 3 ) ) - IF( SCL.NE.ZERO ) THEN - VT( 1 ) = VT( 1 ) / SCL - VT( 2 ) = VT( 2 ) / SCL - VT( 3 ) = VT( 3 ) / SCL - END IF -* -* ==== The following is the traditional and -* . conservative two-small-subdiagonals -* . test. ==== -* . - IF( ABS( H( K+1, K ) )*( ABS( VT( 2 ) )+ - $ ABS( VT( 3 ) ) ).GT.ULP*ABS( VT( 1 ) )* - $ ( ABS( H( K, K ) )+ABS( H( K+1, - $ K+1 ) )+ABS( H( K+2, K+2 ) ) ) ) THEN -* -* ==== Starting a new bulge here would -* . create non-negligible fill. If -* . the old reflector is diagonal (only -* . possible with underflows), then -* . change it to I. Otherwise, use -* . it with trepidation. ==== -* - IF( V( 2, M ).EQ.ZERO .AND. V( 3, M ).EQ.ZERO ) - $ THEN - V( 1, M ) = ZERO - ELSE - H( K+1, K ) = BETA - H( K+2, K ) = ZERO - H( K+3, K ) = ZERO - END IF - ELSE -* -* ==== Stating a new bulge here would -* . create only negligible fill. -* . Replace the old reflector with -* . the new one. ==== -* - ALPHA = VT( 1 ) - CALL DLARFG( 3, ALPHA, VT( 2 ), 1, VT( 1 ) ) - REFSUM = H( K+1, K ) + H( K+2, K )*VT( 2 ) + - $ H( K+3, K )*VT( 3 ) - H( K+1, K ) = H( K+1, K ) - VT( 1 )*REFSUM - H( K+2, K ) = ZERO - H( K+3, K ) = ZERO - V( 1, M ) = VT( 1 ) - V( 2, M ) = VT( 2 ) - V( 3, M ) = VT( 3 ) - END IF - END IF - END IF - 20 CONTINUE -* -* ==== Generate a 2-by-2 reflection, if needed. ==== -* - K = KRCOL + 3*( M22-1 ) - IF( BMP22 ) THEN - IF( K.EQ.KTOP-1 ) THEN - CALL DLAQR1( 2, H( K+1, K+1 ), LDH, SR( 2*M22-1 ), - $ SI( 2*M22-1 ), SR( 2*M22 ), SI( 2*M22 ), - $ V( 1, M22 ) ) - BETA = V( 1, M22 ) - CALL DLARFG( 2, BETA, V( 2, M22 ), 1, V( 1, M22 ) ) - ELSE - BETA = H( K+1, K ) - V( 2, M22 ) = H( K+2, K ) - CALL DLARFG( 2, BETA, V( 2, M22 ), 1, V( 1, M22 ) ) - H( K+1, K ) = BETA - H( K+2, K ) = ZERO - END IF - ELSE -* -* ==== Initialize V(1,M22) here to avoid possible undefined -* . variable problems later. ==== -* - V( 1, M22 ) = ZERO - END IF -* -* ==== Multiply H by reflections from the left ==== -* - IF( ACCUM ) THEN - JBOT = MIN( NDCOL, KBOT ) - ELSE IF( WANTT ) THEN - JBOT = N - ELSE - JBOT = KBOT - END IF - DO 40 J = MAX( KTOP, KRCOL ), JBOT - MEND = MIN( MBOT, ( J-KRCOL+2 ) / 3 ) - DO 30 M = MTOP, MEND - K = KRCOL + 3*( M-1 ) - REFSUM = V( 1, M )*( H( K+1, J )+V( 2, M )* - $ H( K+2, J )+V( 3, M )*H( K+3, J ) ) - H( K+1, J ) = H( K+1, J ) - REFSUM - H( K+2, J ) = H( K+2, J ) - REFSUM*V( 2, M ) - H( K+3, J ) = H( K+3, J ) - REFSUM*V( 3, M ) - 30 CONTINUE - 40 CONTINUE - IF( BMP22 ) THEN - K = KRCOL + 3*( M22-1 ) - DO 50 J = MAX( K+1, KTOP ), JBOT - REFSUM = V( 1, M22 )*( H( K+1, J )+V( 2, M22 )* - $ H( K+2, J ) ) - H( K+1, J ) = H( K+1, J ) - REFSUM - H( K+2, J ) = H( K+2, J ) - REFSUM*V( 2, M22 ) - 50 CONTINUE - END IF -* -* ==== Multiply H by reflections from the right. -* . Delay filling in the last row until the -* . vigilant deflation check is complete. ==== -* - IF( ACCUM ) THEN - JTOP = MAX( KTOP, INCOL ) - ELSE IF( WANTT ) THEN - JTOP = 1 - ELSE - JTOP = KTOP - END IF - DO 90 M = MTOP, MBOT - IF( V( 1, M ).NE.ZERO ) THEN - K = KRCOL + 3*( M-1 ) - DO 60 J = JTOP, MIN( KBOT, K+3 ) - REFSUM = V( 1, M )*( H( J, K+1 )+V( 2, M )* - $ H( J, K+2 )+V( 3, M )*H( J, K+3 ) ) - H( J, K+1 ) = H( J, K+1 ) - REFSUM - H( J, K+2 ) = H( J, K+2 ) - REFSUM*V( 2, M ) - H( J, K+3 ) = H( J, K+3 ) - REFSUM*V( 3, M ) - 60 CONTINUE -* - IF( ACCUM ) THEN -* -* ==== Accumulate U. (If necessary, update Z later -* . with with an efficient matrix-matrix -* . multiply.) ==== -* - KMS = K - INCOL - DO 70 J = MAX( 1, KTOP-INCOL ), KDU - REFSUM = V( 1, M )*( U( J, KMS+1 )+V( 2, M )* - $ U( J, KMS+2 )+V( 3, M )*U( J, KMS+3 ) ) - U( J, KMS+1 ) = U( J, KMS+1 ) - REFSUM - U( J, KMS+2 ) = U( J, KMS+2 ) - REFSUM*V( 2, M ) - U( J, KMS+3 ) = U( J, KMS+3 ) - REFSUM*V( 3, M ) - 70 CONTINUE - ELSE IF( WANTZ ) THEN -* -* ==== U is not accumulated, so update Z -* . now by multiplying by reflections -* . from the right. ==== -* - DO 80 J = ILOZ, IHIZ - REFSUM = V( 1, M )*( Z( J, K+1 )+V( 2, M )* - $ Z( J, K+2 )+V( 3, M )*Z( J, K+3 ) ) - Z( J, K+1 ) = Z( J, K+1 ) - REFSUM - Z( J, K+2 ) = Z( J, K+2 ) - REFSUM*V( 2, M ) - Z( J, K+3 ) = Z( J, K+3 ) - REFSUM*V( 3, M ) - 80 CONTINUE - END IF - END IF - 90 CONTINUE -* -* ==== Special case: 2-by-2 reflection (if needed) ==== -* - K = KRCOL + 3*( M22-1 ) - IF( BMP22 .AND. ( V( 1, M22 ).NE.ZERO ) ) THEN - DO 100 J = JTOP, MIN( KBOT, K+3 ) - REFSUM = V( 1, M22 )*( H( J, K+1 )+V( 2, M22 )* - $ H( J, K+2 ) ) - H( J, K+1 ) = H( J, K+1 ) - REFSUM - H( J, K+2 ) = H( J, K+2 ) - REFSUM*V( 2, M22 ) - 100 CONTINUE -* - IF( ACCUM ) THEN - KMS = K - INCOL - DO 110 J = MAX( 1, KTOP-INCOL ), KDU - REFSUM = V( 1, M22 )*( U( J, KMS+1 )+V( 2, M22 )* - $ U( J, KMS+2 ) ) - U( J, KMS+1 ) = U( J, KMS+1 ) - REFSUM - U( J, KMS+2 ) = U( J, KMS+2 ) - REFSUM*V( 2, M22 ) - 110 CONTINUE - ELSE IF( WANTZ ) THEN - DO 120 J = ILOZ, IHIZ - REFSUM = V( 1, M22 )*( Z( J, K+1 )+V( 2, M22 )* - $ Z( J, K+2 ) ) - Z( J, K+1 ) = Z( J, K+1 ) - REFSUM - Z( J, K+2 ) = Z( J, K+2 ) - REFSUM*V( 2, M22 ) - 120 CONTINUE - END IF - END IF -* -* ==== Vigilant deflation check ==== -* - MSTART = MTOP - IF( KRCOL+3*( MSTART-1 ).LT.KTOP ) - $ MSTART = MSTART + 1 - MEND = MBOT - IF( BMP22 ) - $ MEND = MEND + 1 - IF( KRCOL.EQ.KBOT-2 ) - $ MEND = MEND + 1 - DO 130 M = MSTART, MEND - K = MIN( KBOT-1, KRCOL+3*( M-1 ) ) -* -* ==== The following convergence test requires that -* . the tradition small-compared-to-nearby-diagonals -* . criterion and the Ahues & Tisseur (LAWN 122, 1997) -* . criteria both be satisfied. The latter improves -* . accuracy in some examples. Falling back on an -* . alternate convergence criterion when TST1 or TST2 -* . is zero (as done here) is traditional but probably -* . unnecessary. ==== -* - IF( H( K+1, K ).NE.ZERO ) THEN - TST1 = ABS( H( K, K ) ) + ABS( H( K+1, K+1 ) ) - IF( TST1.EQ.ZERO ) THEN - IF( K.GE.KTOP+1 ) - $ TST1 = TST1 + ABS( H( K, K-1 ) ) - IF( K.GE.KTOP+2 ) - $ TST1 = TST1 + ABS( H( K, K-2 ) ) - IF( K.GE.KTOP+3 ) - $ TST1 = TST1 + ABS( H( K, K-3 ) ) - IF( K.LE.KBOT-2 ) - $ TST1 = TST1 + ABS( H( K+2, K+1 ) ) - IF( K.LE.KBOT-3 ) - $ TST1 = TST1 + ABS( H( K+3, K+1 ) ) - IF( K.LE.KBOT-4 ) - $ TST1 = TST1 + ABS( H( K+4, K+1 ) ) - END IF - IF( ABS( H( K+1, K ) ).LE.MAX( SMLNUM, ULP*TST1 ) ) - $ THEN - H12 = MAX( ABS( H( K+1, K ) ), ABS( H( K, K+1 ) ) ) - H21 = MIN( ABS( H( K+1, K ) ), ABS( H( K, K+1 ) ) ) - H11 = MAX( ABS( H( K+1, K+1 ) ), - $ ABS( H( K, K )-H( K+1, K+1 ) ) ) - H22 = MIN( ABS( H( K+1, K+1 ) ), - $ ABS( H( K, K )-H( K+1, K+1 ) ) ) - SCL = H11 + H12 - TST2 = H22*( H11 / SCL ) -* - IF( TST2.EQ.ZERO .OR. H21*( H12 / SCL ).LE. - $ MAX( SMLNUM, ULP*TST2 ) )H( K+1, K ) = ZERO - END IF - END IF - 130 CONTINUE -* -* ==== Fill in the last row of each bulge. ==== -* - MEND = MIN( NBMPS, ( KBOT-KRCOL-1 ) / 3 ) - DO 140 M = MTOP, MEND - K = KRCOL + 3*( M-1 ) - REFSUM = V( 1, M )*V( 3, M )*H( K+4, K+3 ) - H( K+4, K+1 ) = -REFSUM - H( K+4, K+2 ) = -REFSUM*V( 2, M ) - H( K+4, K+3 ) = H( K+4, K+3 ) - REFSUM*V( 3, M ) - 140 CONTINUE -* -* ==== End of near-the-diagonal bulge chase. ==== -* - 150 CONTINUE -* -* ==== Use U (if accumulated) to update far-from-diagonal -* . entries in H. If required, use U to update Z as -* . well. ==== -* - IF( ACCUM ) THEN - IF( WANTT ) THEN - JTOP = 1 - JBOT = N - ELSE - JTOP = KTOP - JBOT = KBOT - END IF - IF( ( .NOT.BLK22 ) .OR. ( INCOL.LT.KTOP ) .OR. - $ ( NDCOL.GT.KBOT ) .OR. ( NS.LE.2 ) ) THEN -* -* ==== Updates not exploiting the 2-by-2 block -* . structure of U. K1 and NU keep track of -* . the location and size of U in the special -* . cases of introducing bulges and chasing -* . bulges off the bottom. In these special -* . cases and in case the number of shifts -* . is NS = 2, there is no 2-by-2 block -* . structure to exploit. ==== -* - K1 = MAX( 1, KTOP-INCOL ) - NU = ( KDU-MAX( 0, NDCOL-KBOT ) ) - K1 + 1 -* -* ==== Horizontal Multiply ==== -* - DO 160 JCOL = MIN( NDCOL, KBOT ) + 1, JBOT, NH - JLEN = MIN( NH, JBOT-JCOL+1 ) - CALL DGEMM( 'C', 'N', NU, JLEN, NU, ONE, U( K1, K1 ), - $ LDU, H( INCOL+K1, JCOL ), LDH, ZERO, WH, - $ LDWH ) - CALL DLACPY( 'ALL', NU, JLEN, WH, LDWH, - $ H( INCOL+K1, JCOL ), LDH ) - 160 CONTINUE -* -* ==== Vertical multiply ==== -* - DO 170 JROW = JTOP, MAX( KTOP, INCOL ) - 1, NV - JLEN = MIN( NV, MAX( KTOP, INCOL )-JROW ) - CALL DGEMM( 'N', 'N', JLEN, NU, NU, ONE, - $ H( JROW, INCOL+K1 ), LDH, U( K1, K1 ), - $ LDU, ZERO, WV, LDWV ) - CALL DLACPY( 'ALL', JLEN, NU, WV, LDWV, - $ H( JROW, INCOL+K1 ), LDH ) - 170 CONTINUE -* -* ==== Z multiply (also vertical) ==== -* - IF( WANTZ ) THEN - DO 180 JROW = ILOZ, IHIZ, NV - JLEN = MIN( NV, IHIZ-JROW+1 ) - CALL DGEMM( 'N', 'N', JLEN, NU, NU, ONE, - $ Z( JROW, INCOL+K1 ), LDZ, U( K1, K1 ), - $ LDU, ZERO, WV, LDWV ) - CALL DLACPY( 'ALL', JLEN, NU, WV, LDWV, - $ Z( JROW, INCOL+K1 ), LDZ ) - 180 CONTINUE - END IF - ELSE -* -* ==== Updates exploiting U's 2-by-2 block structure. -* . (I2, I4, J2, J4 are the last rows and columns -* . of the blocks.) ==== -* - I2 = ( KDU+1 ) / 2 - I4 = KDU - J2 = I4 - I2 - J4 = KDU -* -* ==== KZS and KNZ deal with the band of zeros -* . along the diagonal of one of the triangular -* . blocks. ==== -* - KZS = ( J4-J2 ) - ( NS+1 ) - KNZ = NS + 1 -* -* ==== Horizontal multiply ==== -* - DO 190 JCOL = MIN( NDCOL, KBOT ) + 1, JBOT, NH - JLEN = MIN( NH, JBOT-JCOL+1 ) -* -* ==== Copy bottom of H to top+KZS of scratch ==== -* (The first KZS rows get multiplied by zero.) ==== -* - CALL DLACPY( 'ALL', KNZ, JLEN, H( INCOL+1+J2, JCOL ), - $ LDH, WH( KZS+1, 1 ), LDWH ) -* -* ==== Multiply by U21' ==== -* - CALL DLASET( 'ALL', KZS, JLEN, ZERO, ZERO, WH, LDWH ) - CALL DTRMM( 'L', 'U', 'C', 'N', KNZ, JLEN, ONE, - $ U( J2+1, 1+KZS ), LDU, WH( KZS+1, 1 ), - $ LDWH ) -* -* ==== Multiply top of H by U11' ==== -* - CALL DGEMM( 'C', 'N', I2, JLEN, J2, ONE, U, LDU, - $ H( INCOL+1, JCOL ), LDH, ONE, WH, LDWH ) -* -* ==== Copy top of H bottom of WH ==== -* - CALL DLACPY( 'ALL', J2, JLEN, H( INCOL+1, JCOL ), LDH, - $ WH( I2+1, 1 ), LDWH ) -* -* ==== Multiply by U21' ==== -* - CALL DTRMM( 'L', 'L', 'C', 'N', J2, JLEN, ONE, - $ U( 1, I2+1 ), LDU, WH( I2+1, 1 ), LDWH ) -* -* ==== Multiply by U22 ==== -* - CALL DGEMM( 'C', 'N', I4-I2, JLEN, J4-J2, ONE, - $ U( J2+1, I2+1 ), LDU, - $ H( INCOL+1+J2, JCOL ), LDH, ONE, - $ WH( I2+1, 1 ), LDWH ) -* -* ==== Copy it back ==== -* - CALL DLACPY( 'ALL', KDU, JLEN, WH, LDWH, - $ H( INCOL+1, JCOL ), LDH ) - 190 CONTINUE -* -* ==== Vertical multiply ==== -* - DO 200 JROW = JTOP, MAX( INCOL, KTOP ) - 1, NV - JLEN = MIN( NV, MAX( INCOL, KTOP )-JROW ) -* -* ==== Copy right of H to scratch (the first KZS -* . columns get multiplied by zero) ==== -* - CALL DLACPY( 'ALL', JLEN, KNZ, H( JROW, INCOL+1+J2 ), - $ LDH, WV( 1, 1+KZS ), LDWV ) -* -* ==== Multiply by U21 ==== -* - CALL DLASET( 'ALL', JLEN, KZS, ZERO, ZERO, WV, LDWV ) - CALL DTRMM( 'R', 'U', 'N', 'N', JLEN, KNZ, ONE, - $ U( J2+1, 1+KZS ), LDU, WV( 1, 1+KZS ), - $ LDWV ) -* -* ==== Multiply by U11 ==== -* - CALL DGEMM( 'N', 'N', JLEN, I2, J2, ONE, - $ H( JROW, INCOL+1 ), LDH, U, LDU, ONE, WV, - $ LDWV ) -* -* ==== Copy left of H to right of scratch ==== -* - CALL DLACPY( 'ALL', JLEN, J2, H( JROW, INCOL+1 ), LDH, - $ WV( 1, 1+I2 ), LDWV ) -* -* ==== Multiply by U21 ==== -* - CALL DTRMM( 'R', 'L', 'N', 'N', JLEN, I4-I2, ONE, - $ U( 1, I2+1 ), LDU, WV( 1, 1+I2 ), LDWV ) -* -* ==== Multiply by U22 ==== -* - CALL DGEMM( 'N', 'N', JLEN, I4-I2, J4-J2, ONE, - $ H( JROW, INCOL+1+J2 ), LDH, - $ U( J2+1, I2+1 ), LDU, ONE, WV( 1, 1+I2 ), - $ LDWV ) -* -* ==== Copy it back ==== -* - CALL DLACPY( 'ALL', JLEN, KDU, WV, LDWV, - $ H( JROW, INCOL+1 ), LDH ) - 200 CONTINUE -* -* ==== Multiply Z (also vertical) ==== -* - IF( WANTZ ) THEN - DO 210 JROW = ILOZ, IHIZ, NV - JLEN = MIN( NV, IHIZ-JROW+1 ) -* -* ==== Copy right of Z to left of scratch (first -* . KZS columns get multiplied by zero) ==== -* - CALL DLACPY( 'ALL', JLEN, KNZ, - $ Z( JROW, INCOL+1+J2 ), LDZ, - $ WV( 1, 1+KZS ), LDWV ) -* -* ==== Multiply by U12 ==== -* - CALL DLASET( 'ALL', JLEN, KZS, ZERO, ZERO, WV, - $ LDWV ) - CALL DTRMM( 'R', 'U', 'N', 'N', JLEN, KNZ, ONE, - $ U( J2+1, 1+KZS ), LDU, WV( 1, 1+KZS ), - $ LDWV ) -* -* ==== Multiply by U11 ==== -* - CALL DGEMM( 'N', 'N', JLEN, I2, J2, ONE, - $ Z( JROW, INCOL+1 ), LDZ, U, LDU, ONE, - $ WV, LDWV ) -* -* ==== Copy left of Z to right of scratch ==== -* - CALL DLACPY( 'ALL', JLEN, J2, Z( JROW, INCOL+1 ), - $ LDZ, WV( 1, 1+I2 ), LDWV ) -* -* ==== Multiply by U21 ==== -* - CALL DTRMM( 'R', 'L', 'N', 'N', JLEN, I4-I2, ONE, - $ U( 1, I2+1 ), LDU, WV( 1, 1+I2 ), - $ LDWV ) -* -* ==== Multiply by U22 ==== -* - CALL DGEMM( 'N', 'N', JLEN, I4-I2, J4-J2, ONE, - $ Z( JROW, INCOL+1+J2 ), LDZ, - $ U( J2+1, I2+1 ), LDU, ONE, - $ WV( 1, 1+I2 ), LDWV ) -* -* ==== Copy the result back to Z ==== -* - CALL DLACPY( 'ALL', JLEN, KDU, WV, LDWV, - $ Z( JROW, INCOL+1 ), LDZ ) - 210 CONTINUE - END IF - END IF - END IF - 220 CONTINUE -* -* ==== End of DLAQR5 ==== -* - END |