REAL FUNCTION SNRM2F ( N, X, INCX )
* .. Scalar Arguments ..
INTEGER INCX, N
* .. Array Arguments ..
REAL X( * )
* ..
*
* SNRM2 returns the euclidean norm of a vector via the function
* name, so that
*
* SNRM2 := sqrt( x'*x )
*
*
*
* -- This version written on 25-October-1982.
* Modified on 14-October-1993 to inline the call to SLASSQ.
* Sven Hammarling, Nag Ltd.
*
*
* .. Parameters ..
REAL ONE , ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
* .. Local Scalars ..
INTEGER IX
REAL ABSXI, NORM, SCALE, SSQ
* .. Intrinsic Functions ..
INTRINSIC ABS, SQRT
* ..
* .. Executable Statements ..
IF( N.LT.1 .OR. INCX.LT.1 )THEN
NORM = ZERO
ELSE IF( N.EQ.1 )THEN
NORM = ABS( X( 1 ) )
ELSE
SCALE = ZERO
SSQ = ONE
* The following loop is equivalent to this call to the LAPACK
* auxiliary routine:
* CALL SLASSQ( N, X, INCX, SCALE, SSQ )
*
DO 10, IX = 1, 1 + ( N - 1 )*INCX, INCX
IF( X( IX ).NE.ZERO )THEN
ABSXI = ABS( X( IX ) )
IF( SCALE.LT.ABSXI )THEN
SSQ = ONE + SSQ*( SCALE/ABSXI )**2
SCALE = ABSXI
ELSE
SSQ = SSQ + ( ABSXI/SCALE )**2
END IF
END IF
10 CONTINUE
NORM = SCALE * SQRT( SSQ )
END IF
*
SNRM2F = NORM
RETURN
*
* End of SNRM2.
*
END