!>
!> SLASSQ returns the values scale_out and sumsq_out such that
!>
!>    (scale_out**2)*sumsq_out = x( 1 )**2 +...+ x( n )**2 + (scale**2)*sumsq,
!>
!> where x( i ) = X( 1 + ( i - 1 )*INCX ). The value of sumsq is
!> assumed to be non-negative.
!>
!> scale and sumsq must be supplied in SCALE and SUMSQ and
!> scale_out and sumsq_out are overwritten on SCALE and SUMSQ respectively.
!>
!> 

N

!>          N is INTEGER
!>          The number of elements to be used from the vector x.
!> 

X

!>          X is REAL array, dimension (1+(N-1)*abs(INCX))
!>          The vector for which a scaled sum of squares is computed.
!>             x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n.
!> 

INCX

!>          INCX is INTEGER
!>          The increment between successive values of the vector x.
!>          If INCX > 0, X(1+(i-1)*INCX) = x(i) for 1 <= i <= n
!>          If INCX < 0, X(1-(n-i)*INCX) = x(i) for 1 <= i <= n
!>          If INCX = 0, x isn't a vector so there is no need to call
!>          this subroutine. If you call it anyway, it will count x(1)
!>          in the vector norm N times.
!> 

SCALE

!>          SCALE is REAL
!>          On entry, the value scale in the equation above.
!>          On exit, SCALE is overwritten by scale_out, the scaling factor
!>          for the sum of squares.
!> 

SUMSQ

!>          SUMSQ is REAL
!>          On entry, the value sumsq in the equation above.
!>          On exit, SUMSQ is overwritten by sumsq_out, the basic sum of
!>          squares from which scale_out has been factored out.
!> 

Edward Anderson, Lockheed Martin

Weslley Pereira, University of Colorado Denver, USA Nick Papior, Technical University of Denmark, DK

!>
!>  Anderson E. (2017)
!>  Algorithm 978: Safe Scaling in the Level 1 BLAS
!>  ACM Trans Math Softw 44:1--28
!>  https://doi.org/10.1145/3061665
!>
!>  Blue, James L. (1978)
!>  A Portable Fortran Program to Find the Euclidean Norm of a Vector
!>  ACM Trans Math Softw 4:15--23
!>  https://doi.org/10.1145/355769.355771
!>
!>