\brief \b ESMF_DLASSQ \htmlonly Download ESMF_DLASSQ + dependencies [TGZ] [ZIP] [TXT] \endhtmlonly \par Purpose:
\verbatim
ESMF_DLASSQ returns the values scl and smsq such that
( scl2 )*smsq = x( 1 )2 +…+ x( n )2 + ( scale2 )*sumsq,
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. \endverbatim \param[in] N \verbatim N is INTEGER The number of elements to be used from the vector X. \endverbatim
\param[in] X \verbatim X is DOUBLE PRECISION array, dimension (N) The vector for which a scaled sum of squares is computed. x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n. \endverbatim
\param[in] INCX \verbatim INCX is INTEGER The increment between successive values of the vector X. INCX > 0. \endverbatim
\param[in,out] SCALE \verbatim SCALE is 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. \endverbatim
\param[in,out] SUMSQ \verbatim SUMSQ is 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. \endverbatim \author Univ. of Tennessee \author Univ. of California Berkeley \author Univ. of Colorado Denver \author NAG Ltd. \date November 2011 \ingroup auxOTHERauxiliary
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| integer | :: | N | ||||
| double precision | :: | X(*) | ||||
| integer | :: | INCX | ||||
| double precision | :: | SCALE | ||||
| double precision | :: | SUMSQ |