zgegs.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 453 行 · 第 1/3 页

         IF( IINFO.NE.0 ) THEN
            INFO = N + 9
            RETURN
         END IF
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Permute the matrix to make it more nearly triangular
</span><span class="comment">*</span><span class="comment">
</span>      ILEFT = 1
      IRIGHT = N + 1
      IRWORK = IRIGHT + N
      IWORK = 1
      CALL <a name="ZGGBAL.296"></a><a href="zggbal.f.html#ZGGBAL.1">ZGGBAL</a>( <span class="string">'P'</span>, N, A, LDA, B, LDB, ILO, IHI, RWORK( ILEFT ),
     $             RWORK( IRIGHT ), RWORK( IRWORK ), IINFO )
      IF( IINFO.NE.0 ) THEN
         INFO = N + 1
         GO TO 10
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Reduce B to triangular form, and initialize VSL and/or VSR
</span><span class="comment">*</span><span class="comment">
</span>      IROWS = IHI + 1 - ILO
      ICOLS = N + 1 - ILO
      ITAU = IWORK
      IWORK = ITAU + IROWS
      CALL <a name="ZGEQRF.309"></a><a href="zgeqrf.f.html#ZGEQRF.1">ZGEQRF</a>( IROWS, ICOLS, B( ILO, ILO ), LDB, WORK( ITAU ),
     $             WORK( IWORK ), LWORK+1-IWORK, IINFO )
      IF( IINFO.GE.0 )
     $   LWKOPT = MAX( LWKOPT, INT( WORK( IWORK ) )+IWORK-1 )
      IF( IINFO.NE.0 ) THEN
         INFO = N + 2
         GO TO 10
      END IF
<span class="comment">*</span><span class="comment">
</span>      CALL <a name="ZUNMQR.318"></a><a href="zunmqr.f.html#ZUNMQR.1">ZUNMQR</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( IWORK ),
     $             LWORK+1-IWORK, IINFO )
      IF( IINFO.GE.0 )
     $   LWKOPT = MAX( LWKOPT, INT( WORK( IWORK ) )+IWORK-1 )
      IF( IINFO.NE.0 ) THEN
         INFO = N + 3
         GO TO 10
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( ILVSL ) THEN
         CALL <a name="ZLASET.329"></a><a href="zlaset.f.html#ZLASET.1">ZLASET</a>( <span class="string">'Full'</span>, N, N, CZERO, CONE, VSL, LDVSL )
         CALL <a name="ZLACPY.330"></a><a href="zlacpy.f.html#ZLACPY.1">ZLACPY</a>( <span class="string">'L'</span>, IROWS-1, IROWS-1, B( ILO+1, ILO ), LDB,
     $                VSL( ILO+1, ILO ), LDVSL )
         CALL <a name="ZUNGQR.332"></a><a href="zungqr.f.html#ZUNGQR.1">ZUNGQR</a>( IROWS, IROWS, IROWS, VSL( ILO, ILO ), LDVSL,
     $                WORK( ITAU ), WORK( IWORK ), LWORK+1-IWORK,
     $                IINFO )
         IF( IINFO.GE.0 )
     $      LWKOPT = MAX( LWKOPT, INT( WORK( IWORK ) )+IWORK-1 )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 4
            GO TO 10
         END IF
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( ILVSR )
     $   CALL <a name="ZLASET.344"></a><a href="zlaset.f.html#ZLASET.1">ZLASET</a>( <span class="string">'Full'</span>, N, N, CZERO, CONE, VSR, LDVSR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Reduce to generalized Hessenberg form
</span><span class="comment">*</span><span class="comment">
</span>      CALL <a name="ZGGHRD.348"></a><a href="zgghrd.f.html#ZGGHRD.1">ZGGHRD</a>( JOBVSL, JOBVSR, N, ILO, IHI, A, LDA, B, LDB, VSL,
     $             LDVSL, VSR, LDVSR, IINFO )
      IF( IINFO.NE.0 ) THEN
         INFO = N + 5
         GO TO 10
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Perform QZ algorithm, computing Schur vectors if desired
</span><span class="comment">*</span><span class="comment">
</span>      IWORK = ITAU
      CALL <a name="ZHGEQZ.358"></a><a href="zhgeqz.f.html#ZHGEQZ.1">ZHGEQZ</a>( <span class="string">'S'</span>, JOBVSL, JOBVSR, N, ILO, IHI, A, LDA, B, LDB,
     $             ALPHA, BETA, VSL, LDVSL, VSR, LDVSR, WORK( IWORK ),
     $             LWORK+1-IWORK, RWORK( IRWORK ), IINFO )
      IF( IINFO.GE.0 )
     $   LWKOPT = MAX( LWKOPT, INT( WORK( IWORK ) )+IWORK-1 )
      IF( IINFO.NE.0 ) THEN
         IF( IINFO.GT.0 .AND. IINFO.LE.N ) THEN
            INFO = IINFO
         ELSE IF( IINFO.GT.N .AND. IINFO.LE.2*N ) THEN
            INFO = IINFO - N
         ELSE
            INFO = N + 6
         END IF
         GO TO 10
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Apply permutation to VSL and VSR
</span><span class="comment">*</span><span class="comment">
</span>      IF( ILVSL ) THEN
         CALL <a name="ZGGBAK.377"></a><a href="zggbak.f.html#ZGGBAK.1">ZGGBAK</a>( <span class="string">'P'</span>, <span class="string">'L'</span>, N, ILO, IHI, RWORK( ILEFT ),
     $                RWORK( IRIGHT ), N, VSL, LDVSL, IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 7
            GO TO 10
         END IF
      END IF
      IF( ILVSR ) THEN
         CALL <a name="ZGGBAK.385"></a><a href="zggbak.f.html#ZGGBAK.1">ZGGBAK</a>( <span class="string">'P'</span>, <span class="string">'R'</span>, N, ILO, IHI, RWORK( ILEFT ),
     $                RWORK( IRIGHT ), N, VSR, LDVSR, IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 8
            GO TO 10
         END IF
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Undo scaling
</span><span class="comment">*</span><span class="comment">
</span>      IF( ILASCL ) THEN
         CALL <a name="ZLASCL.396"></a><a href="zlascl.f.html#ZLASCL.1">ZLASCL</a>( <span class="string">'U'</span>, -1, -1, ANRMTO, ANRM, N, N, A, LDA, IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 9
            RETURN
         END IF
         CALL <a name="ZLASCL.401"></a><a href="zlascl.f.html#ZLASCL.1">ZLASCL</a>( <span class="string">'G'</span>, -1, -1, ANRMTO, ANRM, N, 1, ALPHA, N, IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 9
            RETURN
         END IF
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( ILBSCL ) THEN
         CALL <a name="ZLASCL.409"></a><a href="zlascl.f.html#ZLASCL.1">ZLASCL</a>( <span class="string">'U'</span>, -1, -1, BNRMTO, BNRM, N, N, B, LDB, IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 9
            RETURN
         END IF
         CALL <a name="ZLASCL.414"></a><a href="zlascl.f.html#ZLASCL.1">ZLASCL</a>( <span class="string">'G'</span>, -1, -1, BNRMTO, BNRM, N, 1, BETA, N, IINFO )
         IF( IINFO.NE.0 ) THEN
            INFO = N + 9
            RETURN
         END IF
      END IF
<span class="comment">*</span><span class="comment">
</span>   10 CONTINUE
      WORK( 1 ) = LWKOPT
<span class="comment">*</span><span class="comment">
</span>      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     End of <a name="ZGEGS.426"></a><a href="zgegs.f.html#ZGEGS.1">ZGEGS</a>
</span><span class="comment">*</span><span class="comment">
</span>      END

</pre>

 </body>
</html>