source: LMDZ5/trunk/libf/cosp/congvec.h @ 1992

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      do irand = 1, npoints
          ! Marsaglia CONG algorithm
          seed(irand)=69069*seed(irand)+1234567
          ! mod 32 bit overflow
          seed(irand)=mod(seed(irand),2**30)   
          ran(irand)=seed(irand)*0.931322574615479E-09
      enddo

      ! convert to range 0-1 (32 bit only)
      overflow_32=i2_16*i2_16
      if ( overflow_32 .le. huge32 ) then
          do irand = 1, npoints
              ran(irand)=ran(irand)+1
              ran(irand)=(ran(irand))-int(ran(irand))
          enddo
      endif