dlassq(3F)

NAME
     DLASSQ - return the values scl and smsq such that   ( scl**2 )*smsq = x(
     1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq,

SYNOPSIS
     SUBROUTINE DLASSQ( N, X, INCX, SCALE, SUMSQ )

         INTEGER        INCX, N

         DOUBLE         PRECISION SCALE, SUMSQ

         DOUBLE         PRECISION X( * )

PURPOSE
     DLASSQ  returns the values  scl  and  smsq  such that

     where  x( i ) = X( 1 + ( i - 1 )*INCX ). The value of  sumsq  is assumed
     to be non-negative and  scl  returns the value

        scl = max( scale, abs( x( i ) ) ).

     scale and sumsq must be supplied in SCALE and SUMSQ and
     scl and smsq are overwritten on SCALE and SUMSQ respectively.

     The routine makes only one pass through the vector x.


ARGUMENTS
     N       (input) INTEGER
             The number of elements to be used from the vector X.

     X       (input) DOUBLE PRECISION
             The vector for which a scaled sum of squares is computed.  x( i )
             = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n.

     INCX    (input) INTEGER
             The increment between successive values of the vector X.  INCX >
             0.

     SCALE   (input/output) DOUBLE PRECISION
             On entry, the value  scale  in the equation above.  On exit,
             SCALE is overwritten with  scl , the scaling factor for the sum
             of squares.

     SUMSQ   (input/output) DOUBLE PRECISION
             On entry, the value  sumsq  in the equation above.  On exit,
             SUMSQ is overwritten with  smsq , the basic sum of squares from
             which  scl  has been factored out.