zlantb.f.html

来自「famous linear algebra library (LAPACK) p」· HTML 代码 · 共 310 行 · 第 1/2 页

            ELSE
               DO 80 J = 1, N
                  DO 70 I = 1, MIN( N+1-J, K+1 )
                     VALUE = MAX( VALUE, ABS( AB( I, J ) ) )
   70             CONTINUE
   80          CONTINUE
            END IF
         END IF
      ELSE IF( ( <a name="LSAME.145"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'O'</span> ) ) .OR. ( NORM.EQ.<span class="string">'1'</span> ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find norm1(A).
</span><span class="comment">*</span><span class="comment">
</span>         VALUE = ZERO
         UDIAG = <a name="LSAME.150"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( DIAG, <span class="string">'U'</span> )
         IF( <a name="LSAME.151"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( UPLO, <span class="string">'U'</span> ) ) THEN
            DO 110 J = 1, N
               IF( UDIAG ) THEN
                  SUM = ONE
                  DO 90 I = MAX( K+2-J, 1 ), K
                     SUM = SUM + ABS( AB( I, J ) )
   90             CONTINUE
               ELSE
                  SUM = ZERO
                  DO 100 I = MAX( K+2-J, 1 ), K + 1
                     SUM = SUM + ABS( AB( I, J ) )
  100             CONTINUE
               END IF
               VALUE = MAX( VALUE, SUM )
  110       CONTINUE
         ELSE
            DO 140 J = 1, N
               IF( UDIAG ) THEN
                  SUM = ONE
                  DO 120 I = 2, MIN( N+1-J, K+1 )
                     SUM = SUM + ABS( AB( I, J ) )
  120             CONTINUE
               ELSE
                  SUM = ZERO
                  DO 130 I = 1, MIN( N+1-J, K+1 )
                     SUM = SUM + ABS( AB( I, J ) )
  130             CONTINUE
               END IF
               VALUE = MAX( VALUE, SUM )
  140       CONTINUE
         END IF
      ELSE IF( <a name="LSAME.182"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'I'</span> ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find normI(A).
</span><span class="comment">*</span><span class="comment">
</span>         VALUE = ZERO
         IF( <a name="LSAME.187"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( UPLO, <span class="string">'U'</span> ) ) THEN
            IF( <a name="LSAME.188"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( DIAG, <span class="string">'U'</span> ) ) THEN
               DO 150 I = 1, N
                  WORK( I ) = ONE
  150          CONTINUE
               DO 170 J = 1, N
                  L = K + 1 - J
                  DO 160 I = MAX( 1, J-K ), J - 1
                     WORK( I ) = WORK( I ) + ABS( AB( L+I, J ) )
  160             CONTINUE
  170          CONTINUE
            ELSE
               DO 180 I = 1, N
                  WORK( I ) = ZERO
  180          CONTINUE
               DO 200 J = 1, N
                  L = K + 1 - J
                  DO 190 I = MAX( 1, J-K ), J
                     WORK( I ) = WORK( I ) + ABS( AB( L+I, J ) )
  190             CONTINUE
  200          CONTINUE
            END IF
         ELSE
            IF( <a name="LSAME.210"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( DIAG, <span class="string">'U'</span> ) ) THEN
               DO 210 I = 1, N
                  WORK( I ) = ONE
  210          CONTINUE
               DO 230 J = 1, N
                  L = 1 - J
                  DO 220 I = J + 1, MIN( N, J+K )
                     WORK( I ) = WORK( I ) + ABS( AB( L+I, J ) )
  220             CONTINUE
  230          CONTINUE
            ELSE
               DO 240 I = 1, N
                  WORK( I ) = ZERO
  240          CONTINUE
               DO 260 J = 1, N
                  L = 1 - J
                  DO 250 I = J, MIN( N, J+K )
                     WORK( I ) = WORK( I ) + ABS( AB( L+I, J ) )
  250             CONTINUE
  260          CONTINUE
            END IF
         END IF
         DO 270 I = 1, N
            VALUE = MAX( VALUE, WORK( I ) )
  270    CONTINUE
      ELSE IF( ( <a name="LSAME.235"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'F'</span> ) ) .OR. ( <a name="LSAME.235"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( NORM, <span class="string">'E'</span> ) ) ) THEN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">        Find normF(A).
</span><span class="comment">*</span><span class="comment">
</span>         IF( <a name="LSAME.239"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( UPLO, <span class="string">'U'</span> ) ) THEN
            IF( <a name="LSAME.240"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( DIAG, <span class="string">'U'</span> ) ) THEN
               SCALE = ONE
               SUM = N
               IF( K.GT.0 ) THEN
                  DO 280 J = 2, N
                     CALL <a name="ZLASSQ.245"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( MIN( J-1, K ),
     $                            AB( MAX( K+2-J, 1 ), J ), 1, SCALE,
     $                            SUM )
  280             CONTINUE
               END IF
            ELSE
               SCALE = ZERO
               SUM = ONE
               DO 290 J = 1, N
                  CALL <a name="ZLASSQ.254"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( MIN( J, K+1 ), AB( MAX( K+2-J, 1 ), J ),
     $                         1, SCALE, SUM )
  290          CONTINUE
            END IF
         ELSE
            IF( <a name="LSAME.259"></a><a href="lsame.f.html#LSAME.1">LSAME</a>( DIAG, <span class="string">'U'</span> ) ) THEN
               SCALE = ONE
               SUM = N
               IF( K.GT.0 ) THEN
                  DO 300 J = 1, N - 1
                     CALL <a name="ZLASSQ.264"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( MIN( N-J, K ), AB( 2, J ), 1, SCALE,
     $                            SUM )
  300             CONTINUE
               END IF
            ELSE
               SCALE = ZERO
               SUM = ONE
               DO 310 J = 1, N
                  CALL <a name="ZLASSQ.272"></a><a href="zlassq.f.html#ZLASSQ.1">ZLASSQ</a>( MIN( N-J+1, K+1 ), AB( 1, J ), 1, SCALE,
     $                         SUM )
  310          CONTINUE
            END IF
         END IF
         VALUE = SCALE*SQRT( SUM )
      END IF
<span class="comment">*</span><span class="comment">
</span>      <a name="ZLANTB.280"></a><a href="zlantb.f.html#ZLANTB.1">ZLANTB</a> = VALUE
      RETURN
<span class="comment">*</span><span class="comment">
</span><span class="comment">*</span><span class="comment">     End of <a name="ZLANTB.283"></a><a href="zlantb.f.html#ZLANTB.1">ZLANTB</a>
</span><span class="comment">*</span><span class="comment">
</span>      END

</pre>

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