[ferret_users] averaging

[nuncio@xxxxxxxxx]

Hi,
      THis must be a naive question.  I have a time axis running from 1:84 and an average
of every three values need to be computed(not a running mean but mean of first 3 values then second 3 values so on). 
I tried with a few ways like t=1:84:3@ave, changing
the axis to real time axis like one starting from 1-jan-1900. The problem is FERRET computes
the average but the first value is the average of the first two values not the first three values
@sum also gives sum of first two values with @ngd showing 2 for the first block.  
here are few outputs

yes? sh grid p
    GRID GIN1
 name       axis              # pts   start                end
 normal    X
 normal    Y
 normal    Z
 TAX1      T                   84 r   1                    84

is the interval is missing here?

list/l=1:6 p
             VARIABLE : P
             FILENAME : p.cdf
             SUBSET   : 6 points (T)
 1   / 1:  0.2661
 2   / 2:  0.3101
 3   / 3:  0.3174
 4   / 4: -0.3617
 5   / 5: -0.1323
 6   / 6: -0.0020

list/l=1:2 p[t=1:84:3@ave]
             VARIABLE : P
                        regrid: 3 delta on T@AVE
             FILENAME : p.cdf
             SUBSET   : 2 points (T)
 1   / 1:  0.2881
 4   / 2: -0.0589
here the fist value is the sum of the first two values 0.2661 and 0.3101
output of @ngd is this
list/l=1:2 p[t=1:84:3@ngd]
             VARIABLE : P (# of points)
                        regrid: 3 delta on T@NGD
             FILENAME : p.cdf
             SUBSET   : 2 points (T)
 1   / 1:  2.000
 4   / 2:  3.000

Why the FERRET is not taking first three values for the first average. 



Nuncio Murukesh, Ph.D
Research Scientist.
National Centre for Antarctic and Ocean Research
Headland Sada, Vasco Da Gama
Goa, 403804
India.
Ph: Cell-91 9890357423
    off- 91 832 2525428