zlaed7.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 289 行 · 第 1/2 页

</span><span class="comment">*</span><span class="comment">         Contains the permutations (from deflation and sorting) to be
</span><span class="comment">*</span><span class="comment">         applied to each eigenblock.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  GIVPTR (input) INTEGER array, dimension (N lg N)
</span><span class="comment">*</span><span class="comment">         Contains a list of pointers which indicate where in GIVCOL a
</span><span class="comment">*</span><span class="comment">         level's Givens rotations are stored.  GIVPTR(i+1) - GIVPTR(i)
</span><span class="comment">*</span><span class="comment">         indicates the number of Givens rotations.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  GIVCOL (input) INTEGER array, dimension (2, N lg N)
</span><span class="comment">*</span><span class="comment">         Each pair of numbers indicates a pair of columns to take place
</span><span class="comment">*</span><span class="comment">         in a Givens rotation.
</span><span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">  GIVNUM (input) DOUBLE PRECISION array, dimension (2, N lg N)
</span><span class="comment">*</span><span class="comment">         Each number indicates the S value to be used in the
</span><span class="comment">*</span><span class="comment">         corresponding Givens rotation.
</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">          &gt; 0:  if INFO = 1, an eigenvalue did not converge
</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">     .. Local Scalars ..
</span>      INTEGER            COLTYP, CURR, I, IDLMDA, INDX,
     $                   INDXC, INDXP, IQ, IW, IZ, K, N1, N2, PTR
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. External Subroutines ..
</span>      EXTERNAL           <a name="DLAED9.155"></a><a href="dlaed9.f.html#DLAED9.1">DLAED9</a>, <a name="DLAEDA.155"></a><a href="dlaeda.f.html#DLAEDA.1">DLAEDA</a>, <a name="DLAMRG.155"></a><a href="dlamrg.f.html#DLAMRG.1">DLAMRG</a>, <a name="XERBLA.155"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>, <a name="ZLACRM.155"></a><a href="zlacrm.f.html#ZLACRM.1">ZLACRM</a>, <a name="ZLAED8.155"></a><a href="zlaed8.f.html#ZLAED8.1">ZLAED8</a>
<span class="comment">*</span><span class="comment">     ..
</span><span class="comment">*</span><span class="comment">     .. Intrinsic Functions ..
</span>      INTRINSIC          MAX, MIN
<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">     Test the input parameters.
</span><span class="comment">*</span><span class="comment">
</span>      INFO = 0
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     IF( ICOMPQ.LT.0 .OR. ICOMPQ.GT.1 ) THEN
</span><span class="comment">*</span><span class="comment">        INFO = -1
</span><span class="comment">*</span><span class="comment">     ELSE IF( N.LT.0 ) THEN
</span>      IF( N.LT.0 ) THEN
         INFO = -1
      ELSE IF( MIN( 1, N ).GT.CUTPNT .OR. N.LT.CUTPNT ) THEN
         INFO = -2
      ELSE IF( QSIZ.LT.N ) THEN
         INFO = -3
      ELSE IF( LDQ.LT.MAX( 1, N ) ) THEN
         INFO = -9
      END IF
      IF( INFO.NE.0 ) THEN
         CALL <a name="XERBLA.179"></a><a href="xerbla.f.html#XERBLA.1">XERBLA</a>( <span class="string">'<a name="ZLAED7.179"></a><a href="zlaed7.f.html#ZLAED7.1">ZLAED7</a>'</span>, -INFO )
         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">     The following values are for bookkeeping purposes only.  They are
</span><span class="comment">*</span><span class="comment">     integer pointers which indicate the portion of the workspace
</span><span class="comment">*</span><span class="comment">     used by a particular array in <a name="DLAED2.190"></a><a href="dlaed2.f.html#DLAED2.1">DLAED2</a> and <a name="SLAED3.190"></a><a href="slaed3.f.html#SLAED3.1">SLAED3</a>.
</span><span class="comment">*</span><span class="comment">
</span>      IZ = 1
      IDLMDA = IZ + N
      IW = IDLMDA + N
      IQ = IW + N
<span class="comment">*</span><span class="comment">
</span>      INDX = 1
      INDXC = INDX + N
      COLTYP = INDXC + N
      INDXP = COLTYP + N
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Form the z-vector which consists of the last row of Q_1 and the
</span><span class="comment">*</span><span class="comment">     first row of Q_2.
</span><span class="comment">*</span><span class="comment">
</span>      PTR = 1 + 2**TLVLS
      DO 10 I = 1, CURLVL - 1
         PTR = PTR + 2**( TLVLS-I )
   10 CONTINUE
      CURR = PTR + CURPBM
      CALL <a name="DLAEDA.210"></a><a href="dlaeda.f.html#DLAEDA.1">DLAEDA</a>( N, TLVLS, CURLVL, CURPBM, PRMPTR, PERM, GIVPTR,
     $             GIVCOL, GIVNUM, QSTORE, QPTR, RWORK( IZ ),
     $             RWORK( IZ+N ), INFO )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     When solving the final problem, we no longer need the stored data,
</span><span class="comment">*</span><span class="comment">     so we will overwrite the data from this level onto the previously
</span><span class="comment">*</span><span class="comment">     used storage space.
</span><span class="comment">*</span><span class="comment">
</span>      IF( CURLVL.EQ.TLVLS ) THEN
         QPTR( CURR ) = 1
         PRMPTR( CURR ) = 1
         GIVPTR( CURR ) = 1
      END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Sort and Deflate eigenvalues.
</span><span class="comment">*</span><span class="comment">
</span>      CALL <a name="ZLAED8.226"></a><a href="zlaed8.f.html#ZLAED8.1">ZLAED8</a>( K, N, QSIZ, Q, LDQ, D, RHO, CUTPNT, RWORK( IZ ),
     $             RWORK( IDLMDA ), WORK, QSIZ, RWORK( IW ),
     $             IWORK( INDXP ), IWORK( INDX ), INDXQ,
     $             PERM( PRMPTR( CURR ) ), GIVPTR( CURR+1 ),
     $             GIVCOL( 1, GIVPTR( CURR ) ),
     $             GIVNUM( 1, GIVPTR( CURR ) ), INFO )
      PRMPTR( CURR+1 ) = PRMPTR( CURR ) + N
      GIVPTR( CURR+1 ) = GIVPTR( CURR+1 ) + GIVPTR( CURR )
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Solve Secular Equation.
</span><span class="comment">*</span><span class="comment">
</span>      IF( K.NE.0 ) THEN
         CALL <a name="DLAED9.238"></a><a href="dlaed9.f.html#DLAED9.1">DLAED9</a>( K, 1, K, N, D, RWORK( IQ ), K, RHO,
     $                RWORK( IDLMDA ), RWORK( IW ),
     $                QSTORE( QPTR( CURR ) ), K, INFO )
         CALL <a name="ZLACRM.241"></a><a href="zlacrm.f.html#ZLACRM.1">ZLACRM</a>( QSIZ, K, WORK, QSIZ, QSTORE( QPTR( CURR ) ), K, Q,
     $                LDQ, RWORK( IQ ) )
         QPTR( CURR+1 ) = QPTR( CURR ) + K**2
         IF( INFO.NE.0 ) THEN
            RETURN
         END IF
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     Prepare the INDXQ sorting premutation.
</span><span class="comment">*</span><span class="comment">
</span>         N1 = K
         N2 = N - K
         CALL <a name="DLAMRG.252"></a><a href="dlamrg.f.html#DLAMRG.1">DLAMRG</a>( N1, N2, D, 1, -1, INDXQ )
      ELSE
         QPTR( CURR+1 ) = QPTR( CURR )
         DO 20 I = 1, N
            INDXQ( I ) = I
   20    CONTINUE
      END IF
<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="ZLAED7.262"></a><a href="zlaed7.f.html#ZLAED7.1">ZLAED7</a>
</span><span class="comment">*</span><span class="comment">
</span>      END

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