cggevx.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 677 行 · 第 1/4 页

</span>      INFO = 0
      LQUERY = ( LWORK.EQ.-1 )
      IF( .NOT.( NOSCL .OR. <a name="LSAME.324"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( BALANC,<span class="string">'S'</span> ) .OR.
     $    <a name="LSAME.325"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( BALANC, <span class="string">'B'</span> ) ) ) THEN
         INFO = -1
      ELSE IF( IJOBVL.LE.0 ) THEN
         INFO = -2
      ELSE IF( IJOBVR.LE.0 ) THEN
         INFO = -3
      ELSE IF( .NOT.( WANTSN .OR. WANTSE .OR. WANTSB .OR. WANTSV ) )
     $          THEN
         INFO = -4
      ELSE IF( N.LT.0 ) THEN
         INFO = -5
      ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
         INFO = -7
      ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
         INFO = -9
      ELSE IF( LDVL.LT.1 .OR. ( ILVL .AND. LDVL.LT.N ) ) THEN
         INFO = -13
      ELSE IF( LDVR.LT.1 .OR. ( ILVR .AND. LDVR.LT.N ) ) THEN
         INFO = -15
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Compute workspace
</span><span class="comment">*</span><span class="comment">      (Note: Comments in the code beginning &quot;Workspace:&quot; describe the
</span><span class="comment">*</span><span class="comment">       minimal amount of workspace needed at that point in the code,
</span><span class="comment">*</span><span class="comment">       as well as the preferred amount for good performance.
</span><span class="comment">*</span><span class="comment">       NB refers to the optimal block size for the immediately
</span><span class="comment">*</span><span class="comment">       following subroutine, as returned by <a name="ILAENV.351"></a><a href="hfy-index.html#ILAENV">ILAENV</a>. The workspace is
</span><span class="comment">*</span><span class="comment">       computed assuming ILO = 1 and IHI = N, the worst case.)
</span><span class="comment">*</span><span class="comment">
</span>      IF( INFO.EQ.0 ) THEN
         IF( N.EQ.0 ) THEN
            MINWRK = 1
            MAXWRK = 1
         ELSE
            MINWRK = 2*N
            IF( WANTSE ) THEN
               MINWRK = 4*N
            ELSE IF( WANTSV .OR. WANTSB ) THEN
               MINWRK = 2*N*( N + 1)
            END IF
            MAXWRK = MINWRK
            MAXWRK = MAX( MAXWRK,
     $                    N + N*<a name="ILAENV.367"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="CGEQRF.367"></a><a href="cgeqrf.f.html#CGEQRF.1">CGEQRF</a>'</span>, <span class="string">' '</span>, N, 1, N, 0 ) )
            MAXWRK = MAX( MAXWRK,
     $                    N + N*<a name="ILAENV.369"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="CUNMQR.369"></a><a href="cunmqr.f.html#CUNMQR.1">CUNMQR</a>'</span>, <span class="string">' '</span>, N, 1, N, 0 ) )
            IF( ILVL ) THEN
               MAXWRK = MAX( MAXWRK, N +
     $                       N*<a name="ILAENV.372"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="CUNGQR.372"></a><a href="cungqr.f.html#CUNGQR.1">CUNGQR</a>'</span>, <span class="string">' '</span>, N, 1, N, 0 ) )
            END IF
         END IF
         WORK( 1 ) = MAXWRK
<span class="comment">*</span><span class="comment">
</span>         IF( LWORK.LT.MINWRK .AND. .NOT.LQUERY ) THEN
            INFO = -25
         END IF
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( INFO.NE.0 ) THEN
         CALL <a name="XERBLA.383"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>( <span class="string">'<a name="CGGEVX.383"></a><a href="cggevx.f.html#CGGEVX.1">CGGEVX</a>'</span>, -INFO )
         RETURN
      ELSE IF( LQUERY ) THEN
         RETURN
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Quick return if possible
</span><span class="comment">*</span><span class="comment">
</span>      IF( N.EQ.0 )
     $   RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Get machine constants
</span><span class="comment">*</span><span class="comment">
</span>      EPS = <a name="SLAMCH.396"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>( <span class="string">'P'</span> )
      SMLNUM = <a name="SLAMCH.397"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>( <span class="string">'S'</span> )
      BIGNUM = ONE / SMLNUM
      CALL <a name="SLABAD.399"></a><a href="slabad.f.html#SLABAD.1">SLABAD</a>( SMLNUM, BIGNUM )
      SMLNUM = SQRT( SMLNUM ) / EPS
      BIGNUM = ONE / SMLNUM
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Scale A if max element outside range [SMLNUM,BIGNUM]
</span><span class="comment">*</span><span class="comment">
</span>      ANRM = <a name="CLANGE.405"></a><a href="clange.f.html#CLANGE.1">CLANGE</a>( <span class="string">'M'</span>, N, N, A, LDA, RWORK )
      ILASCL = .FALSE.
      IF( ANRM.GT.ZERO .AND. ANRM.LT.SMLNUM ) THEN
         ANRMTO = SMLNUM
         ILASCL = .TRUE.
      ELSE IF( ANRM.GT.BIGNUM ) THEN
         ANRMTO = BIGNUM
         ILASCL = .TRUE.
      END IF
      IF( ILASCL )
     $   CALL <a name="CLASCL.415"></a><a href="clascl.f.html#CLASCL.1">CLASCL</a>( <span class="string">'G'</span>, 0, 0, ANRM, ANRMTO, N, N, A, LDA, IERR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Scale B if max element outside range [SMLNUM,BIGNUM]
</span><span class="comment">*</span><span class="comment">
</span>      BNRM = <a name="CLANGE.419"></a><a href="clange.f.html#CLANGE.1">CLANGE</a>( <span class="string">'M'</span>, N, N, B, LDB, RWORK )
      ILBSCL = .FALSE.
      IF( BNRM.GT.ZERO .AND. BNRM.LT.SMLNUM ) THEN
         BNRMTO = SMLNUM
         ILBSCL = .TRUE.
      ELSE IF( BNRM.GT.BIGNUM ) THEN
         BNRMTO = BIGNUM
         ILBSCL = .TRUE.
      END IF
      IF( ILBSCL )
     $   CALL <a name="CLASCL.429"></a><a href="clascl.f.html#CLASCL.1">CLASCL</a>( <span class="string">'G'</span>, 0, 0, BNRM, BNRMTO, N, N, B, LDB, IERR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Permute and/or balance the matrix pair (A,B)
</span><span class="comment">*</span><span class="comment">     (Real Workspace: need 6*N if BALANC = 'S' or 'B', 1 otherwise)
</span><span class="comment">*</span><span class="comment">
</span>      CALL <a name="CGGBAL.434"></a><a href="cggbal.f.html#CGGBAL.1">CGGBAL</a>( BALANC, N, A, LDA, B, LDB, ILO, IHI, LSCALE, RSCALE,
     $             RWORK, IERR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Compute ABNRM and BBNRM
</span><span class="comment">*</span><span class="comment">
</span>      ABNRM = <a name="CLANGE.439"></a><a href="clange.f.html#CLANGE.1">CLANGE</a>( <span class="string">'1'</span>, N, N, A, LDA, RWORK( 1 ) )
      IF( ILASCL ) THEN
         RWORK( 1 ) = ABNRM
         CALL <a name="SLASCL.442"></a><a href="slascl.f.html#SLASCL.1">SLASCL</a>( <span class="string">'G'</span>, 0, 0, ANRMTO, ANRM, 1, 1, RWORK( 1 ), 1,
     $                IERR )
         ABNRM = RWORK( 1 )
      END IF
<span class="comment">*</span><span class="comment">
</span>      BBNRM = <a name="CLANGE.447"></a><a href="clange.f.html#CLANGE.1">CLANGE</a>( <span class="string">'1'</span>, N, N, B, LDB, RWORK( 1 ) )
      IF( ILBSCL ) THEN
         RWORK( 1 ) = BBNRM
         CALL <a name="SLASCL.450"></a><a href="slascl.f.html#SLASCL.1">SLASCL</a>( <span class="string">'G'</span>, 0, 0, BNRMTO, BNRM, 1, 1, RWORK( 1 ), 1,
     $                IERR )
         BBNRM = RWORK( 1 )
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Reduce B to triangular form (QR decomposition of B)
</span><span class="comment">*</span><span class="comment">     (Complex Workspace: need N, prefer N*NB )
</span><span class="comment">*</span><span class="comment">
</span>      IROWS = IHI + 1 - ILO
      IF( ILV .OR. .NOT.WANTSN ) THEN
         ICOLS = N + 1 - ILO
      ELSE
         ICOLS = IROWS
      END IF
      ITAU = 1
      IWRK = ITAU + IROWS
      CALL <a name="CGEQRF.466"></a><a href="cgeqrf.f.html#CGEQRF.1">CGEQRF</a>( IROWS, ICOLS, B( ILO, ILO ), LDB, WORK( ITAU ),
     $             WORK( IWRK ), LWORK+1-IWRK, IERR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Apply the unitary transformation to A
</span><span class="comment">*</span><span class="comment">     (Complex Workspace: need N, prefer N*NB)
</span><span class="comment">*</span><span class="comment">
</span>      CALL <a name="CUNMQR.472"></a><a href="cunmqr.f.html#CUNMQR.1">CUNMQR</a>( <span class="string">'L'</span>, <span class="string">'C'</span>, IROWS, ICOLS, IROWS, B( ILO, ILO ), LDB,
     $             WORK( ITAU ), A( ILO, ILO ), LDA, WORK( IWRK ),
     $             LWORK+1-IWRK, IERR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Initialize VL and/or VR
</span><span class="comment">*</span><span class="comment">     (Workspace: need N, prefer N*NB)
</span><span class="comment">*</span><span class="comment">
</span>      IF( ILVL ) THEN
         CALL <a name="CLASET.480"></a><a href="claset.f.html#CLASET.1">CLASET</a>( <span class="string">'Full'</span>, N, N, CZERO, CONE, VL, LDVL )
         IF( IROWS.GT.1 ) THEN
            CALL <a name="CLACPY.482"></a><a href="clacpy.f.html#CLACPY.1">CLACPY</a>( <span class="string">'L'</span>, IROWS-1, IROWS-1, B( ILO+1, ILO ), LDB,
     $                   VL( ILO+1, ILO ), LDVL )
         END IF
         CALL <a name="CUNGQR.485"></a><a href="cungqr.f.html#CUNGQR.1">CUNGQR</a>( IROWS, IROWS, IROWS, VL( ILO, ILO ), LDVL,
     $                WORK( ITAU ), WORK( IWRK ), LWORK+1-IWRK, IERR )
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( ILVR )
     $   CALL <a name="CLASET.490"></a><a href="claset.f.html#CLASET.1">CLASET</a>( <span class="string">'Full'</span>, N, N, CZERO, CONE, VR, LDVR )
<span class="comment">*</span><span class="comment">