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Patches pour OS/2

    1:       SUBROUTINE ZLASSQ( N, X, INCX, SCALE, SUMSQ )
    2: *
    3: *  -- LAPACK auxiliary routine (version 3.2) --
    4: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
    5: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
    6: *     November 2006
    7: *
    8: *     .. Scalar Arguments ..
    9:       INTEGER            INCX, N
   10:       DOUBLE PRECISION   SCALE, SUMSQ
   11: *     ..
   12: *     .. Array Arguments ..
   13:       COMPLEX*16         X( * )
   14: *     ..
   15: *
   16: *  Purpose
   17: *  =======
   18: *
   19: *  ZLASSQ returns the values scl and ssq such that
   20: *
   21: *     ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq,
   22: *
   23: *  where x( i ) = abs( X( 1 + ( i - 1 )*INCX ) ). The value of sumsq is
   24: *  assumed to be at least unity and the value of ssq will then satisfy
   25: *
   26: *     1.0 .le. ssq .le. ( sumsq + 2*n ).
   27: *
   28: *  scale is assumed to be non-negative and scl returns the value
   29: *
   30: *     scl = max( scale, abs( real( x( i ) ) ), abs( aimag( x( i ) ) ) ),
   31: *            i
   32: *
   33: *  scale and sumsq must be supplied in SCALE and SUMSQ respectively.
   34: *  SCALE and SUMSQ are overwritten by scl and ssq respectively.
   35: *
   36: *  The routine makes only one pass through the vector X.
   37: *
   38: *  Arguments
   39: *  =========
   40: *
   41: *  N       (input) INTEGER
   42: *          The number of elements to be used from the vector X.
   43: *
   44: *  X       (input) COMPLEX*16 array, dimension (N)
   45: *          The vector x as described above.
   46: *             x( i )  = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n.
   47: *
   48: *  INCX    (input) INTEGER
   49: *          The increment between successive values of the vector X.
   50: *          INCX > 0.
   51: *
   52: *  SCALE   (input/output) DOUBLE PRECISION
   53: *          On entry, the value  scale  in the equation above.
   54: *          On exit, SCALE is overwritten with the value  scl .
   55: *
   56: *  SUMSQ   (input/output) DOUBLE PRECISION
   57: *          On entry, the value  sumsq  in the equation above.
   58: *          On exit, SUMSQ is overwritten with the value  ssq .
   59: *
   60: * =====================================================================
   61: *
   62: *     .. Parameters ..
   63:       DOUBLE PRECISION   ZERO
   64:       PARAMETER          ( ZERO = 0.0D+0 )
   65: *     ..
   66: *     .. Local Scalars ..
   67:       INTEGER            IX
   68:       DOUBLE PRECISION   TEMP1
   69: *     ..
   70: *     .. Intrinsic Functions ..
   71:       INTRINSIC          ABS, DBLE, DIMAG
   72: *     ..
   73: *     .. Executable Statements ..
   74: *
   75:       IF( N.GT.0 ) THEN
   76:          DO 10 IX = 1, 1 + ( N-1 )*INCX, INCX
   77:             IF( DBLE( X( IX ) ).NE.ZERO ) THEN
   78:                TEMP1 = ABS( DBLE( X( IX ) ) )
   79:                IF( SCALE.LT.TEMP1 ) THEN
   80:                   SUMSQ = 1 + SUMSQ*( SCALE / TEMP1 )**2
   81:                   SCALE = TEMP1
   82:                ELSE
   83:                   SUMSQ = SUMSQ + ( TEMP1 / SCALE )**2
   84:                END IF
   85:             END IF
   86:             IF( DIMAG( X( IX ) ).NE.ZERO ) THEN
   87:                TEMP1 = ABS( DIMAG( X( IX ) ) )
   88:                IF( SCALE.LT.TEMP1 ) THEN
   89:                   SUMSQ = 1 + SUMSQ*( SCALE / TEMP1 )**2
   90:                   SCALE = TEMP1
   91:                ELSE
   92:                   SUMSQ = SUMSQ + ( TEMP1 / SCALE )**2
   93:                END IF
   94:             END IF
   95:    10    CONTINUE
   96:       END IF
   97: *
   98:       RETURN
   99: *
  100: *     End of ZLASSQ
  101: *
  102:       END