vnorm.f

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      DOUBLE PRECISION FUNCTION vnorm (N, V, W)
CLLL. OPTIMIZE
C-----------------------------------------------------------------------
C THIS FUNCTION ROUTINE COMPUTES THE WEIGHTED ROOT-MEAN-SQUARE NORM
C OF THE VECTOR OF LENGTH N CONTAINED IN THE ARRAY V, WITH WEIGHTS
C CONTAINED IN THE ARRAY W OF LENGTH N..
C   VNORM = SQRT( (1/N) * SUM( V(I)*W(I) )**2 )
C-----------------------------------------------------------------------
      INTEGER n,   i
      DOUBLE PRECISION v, w,   sum
      dimension v(n), w(n)
      sum = 0.0d0
      DO 10 i = 1,n 
 10     sum = sum + (v(i)*w(i))**2
      vnorm = dsqrt(sum/dble(n))      
      RETURN
C----------------------- END OF FUNCTION VNORM -------------------------
      END