[ferret_users] question about @din or @iin

[ferret ocean <ferretocean@xxxxxxxxx>]

 hi, all
    I'm not sure if anybody had ask this question, and I didn't find it from Email archive in PMEL website. My question is about @din, which give us an unaccurate value?
 
 let one=x*x
 list/i=1:3 one[i=@din]
 then Ferret give us:
 
              VARIABLE : X*X
              X        : 0.5 to 3.5 (integrated)
           14.00
 
 Actually, we know integrate x*x from 0.5 to 3.5 (shift 1/2 grid cell in Ferret), is x^3/3 from 0.5 to 3.5, which means (3.5^3-0.5^3)/3=14.25 instead of 14.00.
 
 
 why? the same for @iin, the results of each step is integer, no digit. why?
 
 Any help will be appreciated!
 
 
 Dawn

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