classq (l)  Linux Man Pages
classq: returns the values scl and ssq such that ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq,
NAME
CLASSQ  returns the values scl and ssq such that ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq,SYNOPSIS
 SUBROUTINE CLASSQ(
 N, X, INCX, SCALE, SUMSQ )
 INTEGER INCX, N
 REAL SCALE, SUMSQ
 COMPLEX X( * )
PURPOSE
CLASSQ returns the values scl and ssq such that where x( i ) = abs( X( 1 + ( i  1 )*INCX ) ). The value of sumsq is assumed to be at least unity and the value of ssq will then satisfy1.0 .le. ssq .le.
scale is assumed to be nonnegative and scl returns the value
scl
scale and sumsq must be supplied in SCALE and SUMSQ respectively. SCALE and SUMSQ are overwritten by scl and ssq 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) COMPLEX array, dimension (N)
 The vector x as described above. 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) REAL
 On entry, the value scale in the equation above. On exit, SCALE is overwritten with the value scl .
 SUMSQ (input/output) REAL

On entry, the value sumsq in the equation above.
On exit, SUMSQ is overwritten with the value ssq .