[ncl-talk] missing value and if condition

[Dennis Shea]

Virtually *ALL interpreted languages *[NCL, Python, Matlab, GrADS, ...] are
'slow'. This is often noted for large multiple do loop cases.

The key in any of these languages is to use the utilities:

; check entire array

    if (*any*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/any.shtml>(*ismissing*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/ismissing.shtml>(RH)))
then
        print("RH: _FillValue present skip processing")
    else
'       ...
    end if

---
Some prefer the .not. operator before the *any*

    if (*.not.* *any*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/any.shtml>(*ismissing*
<http://www.ncl.ucar.edu/Document/Functions/Built-in/ismissing.shtml>(RH)))
then
       ...
    else
        print("RH: _FillValue present skip processing"
    end if


---
; check each temporal intex

    do nt=0,ntim-1
         if (*any*(*ismissing*(RH(*nt*,:,:,:)))) then  ;
RH(time,level,lt,lon)
              print("RH: _FillValue present skip processing")
          else
'       ...
         end if
    ...
    end do




On Tue, May 7, 2019 at 2:43 PM Anahita Amiri Farahani <aamir003 at ucr.edu>
wrote:

> Hi all,
>
> I am trying to use if condition in ncl for my case but apparently ncl is
> really slow when the loops are large, do you have any suggestions to modify
> this code:
>
> do i=0,419
> do j=0,95
> do k=0,143
>
> if (ismissing(RH_1(i,j,k))) then
>
> print("Your data is missing. Cannot create plot.")
>
> else
>
> print("You can plot.")
>
> end if
> end do
> end do
> end do
>
> Thanks,
> Ana
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