zgges.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 502 行 · 第 1/3 页

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</span><span class="comment">*</span><span class="comment">          message related to LWORK is issued by <a name="XERBLA.150"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  RWORK   (workspace) DOUBLE PRECISION array, dimension (8*N)
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  BWORK   (workspace) LOGICAL array, dimension (N)
</span><span class="comment">*</span><span class="comment">          Not referenced if SORT = 'N'.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  INFO    (output) INTEGER
</span><span class="comment">*</span><span class="comment">          = 0:  successful exit
</span><span class="comment">*</span><span class="comment">          &lt; 0:  if INFO = -i, the i-th argument had an illegal value.
</span><span class="comment">*</span><span class="comment">          =1,...,N:
</span><span class="comment">*</span><span class="comment">                The QZ iteration failed.  (A,B) are not in Schur
</span><span class="comment">*</span><span class="comment">                form, but ALPHA(j) and BETA(j) should be correct for
</span><span class="comment">*</span><span class="comment">                j=INFO+1,...,N.
</span><span class="comment">*</span><span class="comment">          &gt; N:  =N+1: other than QZ iteration failed in <a name="ZHGEQZ.164"></a><a href="zhgeqz.f.html#ZHGEQZ.1">ZHGEQZ</a>
</span><span class="comment">*</span><span class="comment">                =N+2: after reordering, roundoff changed values of
</span><span class="comment">*</span><span class="comment">                      some complex eigenvalues so that leading
</span><span class="comment">*</span><span class="comment">                      eigenvalues in the Generalized Schur form no
</span><span class="comment">*</span><span class="comment">                      longer satisfy SELCTG=.TRUE.  This could also
</span><span class="comment">*</span><span class="comment">                      be caused due to scaling.
</span><span class="comment">*</span><span class="comment">                =N+3: reordering falied in <a name="ZTGSEN.170"></a><a href="ztgsen.f.html#ZTGSEN.1">ZTGSEN</a>.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  =====================================================================
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     .. Parameters ..
</span>      DOUBLE PRECISION   ZERO, ONE
      PARAMETER          ( ZERO = 0.0D0, ONE = 1.0D0 )
      COMPLEX*16         CZERO, CONE
      PARAMETER          ( CZERO = ( 0.0D0, 0.0D0 ),
     $                   CONE = ( 1.0D0, 0.0D0 ) )
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Local Scalars ..
</span>      LOGICAL            CURSL, ILASCL, ILBSCL, ILVSL, ILVSR, LASTSL,
     $                   LQUERY, WANTST
      INTEGER            I, ICOLS, IERR, IHI, IJOBVL, IJOBVR, ILEFT,
     $                   ILO, IRIGHT, IROWS, IRWRK, ITAU, IWRK, LWKMIN,
     $                   LWKOPT
      DOUBLE PRECISION   ANRM, ANRMTO, BIGNUM, BNRM, BNRMTO, EPS, PVSL,
     $                   PVSR, SMLNUM
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Local Arrays ..
</span>      INTEGER            IDUM( 1 )
      DOUBLE PRECISION   DIF( 2 )
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Subroutines ..
</span>      EXTERNAL           <a name="DLABAD.195"></a><a href="dlabad.f.html#DLABAD.1">DLABAD</a>, <a name="XERBLA.195"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>, <a name="ZGEQRF.195"></a><a href="zgeqrf.f.html#ZGEQRF.1">ZGEQRF</a>, <a name="ZGGBAK.195"></a><a href="zggbak.f.html#ZGGBAK.1">ZGGBAK</a>, <a name="ZGGBAL.195"></a><a href="zggbal.f.html#ZGGBAL.1">ZGGBAL</a>, <a name="ZGGHRD.195"></a><a href="zgghrd.f.html#ZGGHRD.1">ZGGHRD</a>,
     $                   <a name="ZHGEQZ.196"></a><a href="zhgeqz.f.html#ZHGEQZ.1">ZHGEQZ</a>, <a name="ZLACPY.196"></a><a href="zlacpy.f.html#ZLACPY.1">ZLACPY</a>, <a name="ZLASCL.196"></a><a href="zlascl.f.html#ZLASCL.1">ZLASCL</a>, <a name="ZLASET.196"></a><a href="zlaset.f.html#ZLASET.1">ZLASET</a>, <a name="ZTGSEN.196"></a><a href="ztgsen.f.html#ZTGSEN.1">ZTGSEN</a>, <a name="ZUNGQR.196"></a><a href="zungqr.f.html#ZUNGQR.1">ZUNGQR</a>,
     $                   <a name="ZUNMQR.197"></a><a href="zunmqr.f.html#ZUNMQR.1">ZUNMQR</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Functions ..
</span>      LOGICAL            <a name="LSAME.200"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
      INTEGER            <a name="ILAENV.201"></a><a href="hfy-index.html#ILAENV">ILAENV</a>
      DOUBLE PRECISION   <a name="DLAMCH.202"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>, <a name="ZLANGE.202"></a><a href="zlange.f.html#ZLANGE.1">ZLANGE</a>
      EXTERNAL           <a name="LSAME.203"></a><a href="lsame.f.html#LSAME.1">LSAME</a>, <a name="ILAENV.203"></a><a href="hfy-index.html#ILAENV">ILAENV</a>, <a name="DLAMCH.203"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>, <a name="ZLANGE.203"></a><a href="zlange.f.html#ZLANGE.1">ZLANGE</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Intrinsic Functions ..
</span>      INTRINSIC          MAX, SQRT
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Executable Statements ..
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Decode the input arguments
</span><span class="comment">*</span><span class="comment">
</span>      IF( <a name="LSAME.212"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( JOBVSL, <span class="string">'N'</span> ) ) THEN
         IJOBVL = 1
         ILVSL = .FALSE.
      ELSE IF( <a name="LSAME.215"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( JOBVSL, <span class="string">'V'</span> ) ) THEN
         IJOBVL = 2
         ILVSL = .TRUE.
      ELSE
         IJOBVL = -1
         ILVSL = .FALSE.
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( <a name="LSAME.223"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( JOBVSR, <span class="string">'N'</span> ) ) THEN
         IJOBVR = 1
         ILVSR = .FALSE.
      ELSE IF( <a name="LSAME.226"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( JOBVSR, <span class="string">'V'</span> ) ) THEN
         IJOBVR = 2
         ILVSR = .TRUE.
      ELSE
         IJOBVR = -1
         ILVSR = .FALSE.
      END IF
<span class="comment">*</span><span class="comment">
</span>      WANTST = <a name="LSAME.234"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( SORT, <span class="string">'S'</span> )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Test the input arguments
</span><span class="comment">*</span><span class="comment">
</span>      INFO = 0
      LQUERY = ( LWORK.EQ.-1 )
      IF( IJOBVL.LE.0 ) THEN
         INFO = -1
      ELSE IF( IJOBVR.LE.0 ) THEN
         INFO = -2
      ELSE IF( ( .NOT.WANTST ) .AND. ( .NOT.<a name="LSAME.244"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( SORT, <span class="string">'N'</span> ) ) ) THEN
         INFO = -3
      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( LDVSL.LT.1 .OR. ( ILVSL .AND. LDVSL.LT.N ) ) THEN
         INFO = -14
      ELSE IF( LDVSR.LT.1 .OR. ( ILVSR .AND. LDVSR.LT.N ) ) THEN
         INFO = -16
      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.263"></a><a href="hfy-index.html#ILAENV">ILAENV</a>.)
</span><span class="comment">*</span><span class="comment">
</span>      IF( INFO.EQ.0 ) THEN
         LWKMIN = MAX( 1, 2*N )
         LWKOPT = MAX( 1, N + N*<a name="ILAENV.267"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="ZGEQRF.267"></a><a href="zgeqrf.f.html#ZGEQRF.1">ZGEQRF</a>'</span>, <span class="string">' '</span>, N, 1, N, 0 ) )
         LWKOPT = MAX( LWKOPT, N +
     $                 N*<a name="ILAENV.269"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="ZUNMQR.269"></a><a href="zunmqr.f.html#ZUNMQR.1">ZUNMQR</a>'</span>, <span class="string">' '</span>, N, 1, N, -1 ) )
         IF( ILVSL ) THEN
            LWKOPT = MAX( LWKOPT, N +
     $                    N*<a name="ILAENV.272"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="ZUNGQR.272"></a><a href="zungqr.f.html#ZUNGQR.1">ZUNGQR</a>'</span>, <span class="string">' '</span>, N, 1, N, -1 ) )
         END IF
         WORK( 1 ) = LWKOPT
<span class="comment">*</span><span class="comment">
</span>         IF( LWORK.LT.LWKMIN .AND. .NOT.LQUERY )
     $      INFO = -18
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( INFO.NE.0 ) THEN
         CALL <a name="XERBLA.281"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>( <span class="string">'<a name="ZGGES.281"></a><a href="zgges.f.html#ZGGES.1">ZGGES</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 ) THEN
         SDIM = 0
         RETURN
      END IF
<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="DLAMCH.296"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>( <span class="string">'P'</span> )
      SMLNUM = <a name="DLAMCH.297"></a><a href="dlamch.f.html#DLAMCH.1">DLAMCH</a>( <span class="string">'S'</span> )
      BIGNUM = ONE / SMLNUM
      CALL <a name="DLABAD.299"></a><a href="dlabad.f.html#DLABAD.1">DLABAD</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="ZLANGE.305"></a><a href="zlange.f.html#ZLANGE.1">ZLANGE</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
<span class="comment">*</span><span class="comment">
</span>      IF( ILASCL )
     $   CALL <a name="ZLASCL.316"></a><a href="zlascl.f.html#ZLASCL.1">ZLASCL</a>( <span class="string">'G'</span>, 0, 0, ANRM, ANRMTO, N, N, A, LDA, IERR )
<span class="comment">*</span><span class="comment">
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本页面展示了「famous linear algebra library (LAPACK) ports to windows」中的 zgges.f.html 源码文件，采用 HTML 编程语言编写，共 502 行代码。您可以在线阅读完整代码内容，也可以返回资源详情页下载完整源码包进行本地学习和开发。

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