cgegs.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 452 行 · 第 1/3 页

</span><span class="comment">*</span><span class="comment">                =N+5: error return from <a name="CGGHRD.133"></a><a href="cgghrd.f.html#CGGHRD.1">CGGHRD</a>
</span><span class="comment">*</span><span class="comment">                =N+6: error return from <a name="CHGEQZ.134"></a><a href="chgeqz.f.html#CHGEQZ.1">CHGEQZ</a> (other than failed
</span><span class="comment">*</span><span class="comment">                                               iteration)
</span><span class="comment">*</span><span class="comment">                =N+7: error return from <a name="CGGBAK.136"></a><a href="cggbak.f.html#CGGBAK.1">CGGBAK</a> (computing VSL)
</span><span class="comment">*</span><span class="comment">                =N+8: error return from <a name="CGGBAK.137"></a><a href="cggbak.f.html#CGGBAK.1">CGGBAK</a> (computing VSR)
</span><span class="comment">*</span><span class="comment">                =N+9: error return from <a name="CLASCL.138"></a><a href="clascl.f.html#CLASCL.1">CLASCL</a> (various places)
</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>      REAL               ZERO, ONE
      PARAMETER          ( ZERO = 0.0E0, ONE = 1.0E0 )
      COMPLEX            CZERO, CONE
      PARAMETER          ( CZERO = ( 0.0E0, 0.0E0 ),
     $                   CONE = ( 1.0E0, 0.0E0 ) )
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Local Scalars ..
</span>      LOGICAL            ILASCL, ILBSCL, ILVSL, ILVSR, LQUERY
      INTEGER            ICOLS, IHI, IINFO, IJOBVL, IJOBVR, ILEFT,
     $                   ILO, IRIGHT, IROWS, IRWORK, ITAU, IWORK,
     $                   LOPT, LWKMIN, LWKOPT, NB, NB1, NB2, NB3
      REAL               ANRM, ANRMTO, BIGNUM, BNRM, BNRMTO, EPS,
     $                   SAFMIN, SMLNUM
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Subroutines ..
</span>      EXTERNAL           <a name="CGEQRF.158"></a><a href="cgeqrf.f.html#CGEQRF.1">CGEQRF</a>, <a name="CGGBAK.158"></a><a href="cggbak.f.html#CGGBAK.1">CGGBAK</a>, <a name="CGGBAL.158"></a><a href="cggbal.f.html#CGGBAL.1">CGGBAL</a>, <a name="CGGHRD.158"></a><a href="cgghrd.f.html#CGGHRD.1">CGGHRD</a>, <a name="CHGEQZ.158"></a><a href="chgeqz.f.html#CHGEQZ.1">CHGEQZ</a>, <a name="CLACPY.158"></a><a href="clacpy.f.html#CLACPY.1">CLACPY</a>,
     $                   <a name="CLASCL.159"></a><a href="clascl.f.html#CLASCL.1">CLASCL</a>, <a name="CLASET.159"></a><a href="claset.f.html#CLASET.1">CLASET</a>, <a name="CUNGQR.159"></a><a href="cungqr.f.html#CUNGQR.1">CUNGQR</a>, <a name="CUNMQR.159"></a><a href="cunmqr.f.html#CUNMQR.1">CUNMQR</a>, <a name="XERBLA.159"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Functions ..
</span>      LOGICAL            <a name="LSAME.162"></a><a href="lsame.f.html#LSAME.1">LSAME</a>
      INTEGER            <a name="ILAENV.163"></a><a href="hfy-index.html#ILAENV">ILAENV</a>
      REAL               <a name="CLANGE.164"></a><a href="clange.f.html#CLANGE.1">CLANGE</a>, <a name="SLAMCH.164"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>
      EXTERNAL           <a name="ILAENV.165"></a><a href="hfy-index.html#ILAENV">ILAENV</a>, <a name="LSAME.165"></a><a href="lsame.f.html#LSAME.1">LSAME</a>, <a name="CLANGE.165"></a><a href="clange.f.html#CLANGE.1">CLANGE</a>, <a name="SLAMCH.165"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Intrinsic Functions ..
</span>      INTRINSIC          INT, MAX
<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.174"></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.177"></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.185"></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.188"></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><span class="comment">*</span><span class="comment">     Test the input arguments
</span><span class="comment">*</span><span class="comment">
</span>      LWKMIN = MAX( 2*N, 1 )
      LWKOPT = LWKMIN
      WORK( 1 ) = LWKOPT
      LQUERY = ( LWORK.EQ.-1 )
      INFO = 0
      IF( IJOBVL.LE.0 ) THEN
         INFO = -1
      ELSE IF( IJOBVR.LE.0 ) THEN
         INFO = -2
      ELSE IF( N.LT.0 ) THEN
         INFO = -3
      ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
         INFO = -5
      ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
         INFO = -7
      ELSE IF( LDVSL.LT.1 .OR. ( ILVSL .AND. LDVSL.LT.N ) ) THEN
         INFO = -11
      ELSE IF( LDVSR.LT.1 .OR. ( ILVSR .AND. LDVSR.LT.N ) ) THEN
         INFO = -13
      ELSE IF( LWORK.LT.LWKMIN .AND. .NOT.LQUERY ) THEN
         INFO = -15
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( INFO.EQ.0 ) THEN
         NB1 = <a name="ILAENV.222"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="CGEQRF.222"></a><a href="cgeqrf.f.html#CGEQRF.1">CGEQRF</a>'</span>, <span class="string">' '</span>, N, N, -1, -1 )
         NB2 = <a name="ILAENV.223"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="CUNMQR.223"></a><a href="cunmqr.f.html#CUNMQR.1">CUNMQR</a>'</span>, <span class="string">' '</span>, N, N, N, -1 )
         NB3 = <a name="ILAENV.224"></a><a href="hfy-index.html#ILAENV">ILAENV</a>( 1, <span class="string">'<a name="CUNGQR.224"></a><a href="cungqr.f.html#CUNGQR.1">CUNGQR</a>'</span>, <span class="string">' '</span>, N, N, N, -1 )
         NB = MAX( NB1, NB2, NB3 )
         LOPT = N*(NB+1)
         WORK( 1 ) = LOPT
      END IF
<span class="comment">*</span><span class="comment">
</span>      IF( INFO.NE.0 ) THEN
         CALL <a name="XERBLA.231"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>( <span class="string">'<a name="CGEGS.231"></a><a href="cgegs.f.html#CGEGS.1">CGEGS</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.244"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>( <span class="string">'E'</span> )*<a name="SLAMCH.244"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>( <span class="string">'B'</span> )
      SAFMIN = <a name="SLAMCH.245"></a><a href="slamch.f.html#SLAMCH.1">SLAMCH</a>( <span class="string">'S'</span> )
      SMLNUM = N*SAFMIN / 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.251"></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
<span class="comment">*</span><span class="comment">
</span>      IF( ILASCL ) THEN
         CALL <a name="CLASCL.262"></a><a href="clascl.f.html#CLASCL.1">CLASCL</a>( <span class="string">'G'</span>, -1, -1, ANRM, ANRMTO, N, N, A, LDA, IINFO )
         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">     Scale B if max element outside range [SMLNUM,BIGNUM]
</span><span class="comment">*</span><span class="comment">
</span>      BNRM = <a name="CLANGE.271"></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
<span class="comment">*</span><span class="comment">
</span>      IF( ILBSCL ) THEN
         CALL <a name="CLASCL.282"></a><a href="clascl.f.html#CLASCL.1">CLASCL</a>( <span class="string">'G'</span>, -1, -1, BNRM, BNRMTO, N, N, B, LDB, IINFO )
         IF( IINFO.NE.0 ) THEN