Source module last modified on Thu, 2 Jul 1998, 23:17;
HTML image of Fortran source automatically generated by
for2html on Sun, 23 Jun 2002, 15:10.
REAL FUNCTION SCNRM2( N, X, INCX )
# .. Scalar Arguments ..
INTEGER INCX, N
# .. Array Arguments ..
COMPLEX X( * )
# ..
#
# SCNRM2 returns the euclidean norm of a vector via the function
# name, so that
#
# SCNRM2 := sqrt( conjg( x' )*x )
#
#
#
# -- This version written on 25-October-1982.
# Modified on 14-October-1993 to inline the call to CLASSQ.
# Sven Hammarling, Nag Ltd.
#
#
# .. Parameters ..
REAL ONE , ZERO
PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 )
# .. Local Scalars ..
INTEGER IX
REAL NORM, SCALE, SSQ, TEMP
# .. Intrinsic Functions ..
INTRINSIC ABS, AIMAG, REAL, SQRT
# ..
# .. Executable Statements ..
IF( N<1 || INCX<1 )THEN
NORM = ZERO
ELSE
SCALE = ZERO
SSQ = ONE
# The following loop is equivalent to this call to the LAPACK
# auxiliary routine:
# CALL CLASSQ( N, X, INCX, SCALE, SSQ )
#
DO 10, IX = 1, 1 + ( N - 1 )*INCX, INCX
IF( REAL( X( IX ) )!=ZERO )THEN
TEMP = ABS( REAL( X( IX ) ) )
IF( SCALE<TEMP )THEN
SSQ = ONE + SSQ*( SCALE/TEMP )**2
SCALE = TEMP
ELSE
SSQ = SSQ + ( TEMP/SCALE )**2
END IF
END IF
IF( AIMAG( X( IX ) )!=ZERO )THEN
TEMP = ABS( AIMAG( X( IX ) ) )
IF( SCALE<TEMP )THEN
SSQ = ONE + SSQ*( SCALE/TEMP )**2
SCALE = TEMP
ELSE
SSQ = SSQ + ( TEMP/SCALE )**2
END IF
END IF
10 CONTINUE
NORM = SCALE * SQRT( SSQ )
END IF
#
SCNRM2 = NORM
RETURN
#
# End of SCNRM2.
#
END