[ncl-talk] Regarding to the example 5 of the WRAPIT page
Ng, Kelvin Sai-cheong
kscng at connect.hku.hk
Thu Aug 18 17:58:34 MDT 2016
I see. Thank you Dennis.
Kelvin
On Thu, Aug 18, 2016 at 8:51 PM, Dennis Shea <shea at ucar.edu> wrote:
> The following statement is incorrect.
>
> ===
> But both NCL and FORTRAN have the array convention of
> (number of rows, number of columns)
> ===
>
> fortran is column major
> NCL (think C) is row major.
>
> ====
> NCL/Fortramn argument passing
>
> [1]
> Arrays need no reordering. The 'rule' is: fastest varying dimension in on
> language maps into the fastest varying dimension in the otherv language. In
> NCL, the rightmost dimension is the fastest varying dimension. In Fortran,
> the leftmost dimension is the fastest varying.
>
> NCL Fortran
> x(time,lev,lat,lon) <=map=> x(lon,lat,lev,time)
> [2] Think of an array as being a long 1D list in memory
>
> NCL: x(N,M) Fortran(M,N) where M=3, N=2
>
> memory
> x(0,0) => 7.23 <= x(1,1)
> x(0,1) => -12.5 <= x(2,1)
> x(0,2) => 0.3 <= x(3,1)
>
> x(1,0) => 323.1 <= x(1,2)
> x(1,1) => -234.6 <= x(2,2)
> x(1,2) => 200.1 <= x(3,2)
>
>
> On Thu, Aug 18, 2016 at 1:49 AM, Ng, Kelvin Sai-cheong <
> kscng at connect.hku.hk> wrote:
>
>> Hi,
>>
>> I am just wondering why does the dimension of the input array in NCL
>> (i.e. fxy) has dimension of (n,m), whereas the array in the FORTRAN
>> function (i.e. FXY) has dimension of (m,n)?
>>
>> But both NCL and FORTRAN have the array convention of
>> (number of rows, number of columns).
>>
>> Link: http://www.ncl.ucar.edu/Document/Tools/WRAPIT.shtml#Example_5
>>
>> Many thanks,
>>
>> Kelvin
>>
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