[ncl-talk] How to get the result for each grid?

Rashed Mahmood rashidcomsis at gmail.com
Tue Sep 10 01:31:38 MDT 2019 

The message is clear. You would need to decide what should happen if any
point of your dividing array has 0 value...

I would suggest that you make the dividing arrays separately and use
"where" function to handle grid points with 0 values. Please read
documentation for "where" function:
https://www.ncl.ucar.edu/Document/Functions/Built-in/where.shtmlhttps://www.ncl.ucar.edu/Document/Functions/Built-in/where.shtml


On Tue, Sep 10, 2019 at 8:02 AM Atul Saini <atulsainimail at gmail.com> wrote:

> Yes, you are right there was some issues with the data file now it's
> working fine. But after executing the users function it's giving the
> message having issue you in dividing by zero.
> The code is as follows-
>
> *While running the following code-*
>
> a=addfile("Data_File.nc","r")
> x=a->tym(0:4,:,:)
> X=sqrt(x)
> y=a->rf(0:4,:,:)
> Y=sqrt(y)
> v=a->tym(5:9,:,:)
> V=sqrt(v)
> w=a->rf(5:9,:,:)
> W=sqrt(w)
>
> A1=((dim_sum_n(y,0))*(dim_sum_n(X,0)))-(dim_sum_n(x,0))*(dim_sum_n(x*y,0))/(100*(dim_sum_n(X,0))-(sqrt(dim_sum_n(x,0))))
>
>
> A2=((dim_sum_n(w,0))*(dim_sum_n(V,0)))-(dim_sum_n(v,0))*(dim_sum_n(v*w,0))/(100*(dim_sum_n(V,0))-(sqrt(dim_sum_n(v,0))))
>
> B1=
> (100*(dim_sum_n(x*y,0)))-(dim_sum_n(y,0))/(100*(dim_sum_n(X,0))-(sqrt(dim_sum_n(x,0))))
>
> B2=
> (100*(dim_sum_n(v*w,0)))-(dim_sum_n(w,0))/(100*(dim_sum_n(V,0))-(sqrt(dim_sum_n(v,0))))
>
> chpOnset = ((A1-A2)/(B2-B1))
> print(chpOnset)
>
> *I am receiving the following error-*
> fatal:divide: Division by 0, Can't continue
> fatal:Div: operator failed, can't continue
>
> On Mon, Sep 9, 2019, 17:04 Atul Saini <atulsainimail at gmail.com> wrote:
>
>> Ok, I will check and let you know.
>>
>>
>> On Mon, Sep 9, 2019, 17:04 Rashed Mahmood <rashidcomsis at gmail.com> wrote:
>>
>>>
>>> Are you sure about the data file? Why got no values for x min and max?
>>> Also why was the min and max same value for X, 5050?
>>>
>>> There is no problem with function, I am sure. It's the data file that
>>> need to be checked thoroughly? If you cannot find issue with the file you
>>> would need provide the data file to the list.
>>>
>>>
>>>
>>>
>>> On Mon, Sep 9, 2019 at 1:26 PM Atul Saini <atulsainimail at gmail.com>
>>> wrote:
>>>
>>>> I got the following answer-
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *ncl 6> printVarSummary(x)Variable: xType: floatTotal Size: 6966000
>>>> bytes            1741500 valuesNumber of Dimensions: 3Dimensions and sizes:
>>>> [time | 100] x [lat | 129] x [lon | 135]Coordinates:             time: [
>>>> 1.. 100]            lat: [6.5..38.5]            lon: [66.5..100]Number Of
>>>> Attributes: 3  long_name : GRIDDED RAINFALL  _FillValue : -999
>>>> missing_value : -999ncl 7> printVarSummary(X)Variable: XType: floatTotal
>>>> Size: 69660 bytes            17415 valuesNumber of Dimensions: 2Dimensions
>>>> and sizes: [129] x [135]Coordinates: Number Of Attributes: 1  _FillValue :
>>>> -999ncl 8> ncl 9> print(x at _FillValue)(0) -999ncl 10> print(X at _FillValue)(0)
>>>> -999*
>>>> Regards,
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Mon, Sep 9, 2019 at 4:46 PM Rashed Mahmood <rashidcomsis at gmail.com>
>>>> wrote:
>>>>
>>>>> Why there are no values for min and max of x variable?
>>>>> I suspect that there is something wrong with your data file, however,
>>>>> you should do some more checking... e.g.
>>>>>
>>>>> printVarSummary(x)
>>>>> printVarSummary(X)
>>>>>
>>>>> print(x at _FillValue)
>>>>> print(X at _FillValue)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Mon, Sep 9, 2019 at 1:11 PM Atul Saini <atulsainimail at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Rashed sir,
>>>>>>                   It gives the following answer-
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> *ncl 4> printMinMax(x,True)(0) (0) GRIDDED RAINFALLncl 5>
>>>>>> printMinMax(X,True)(0) (0) min=5050   max=5050*
>>>>>>
>>>>>> Regards,
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 9, 2019 at 4:38 PM Rashed Mahmood <rashidcomsis at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> I do not see any problem with the lines you just posted.
>>>>>>> Can you add following in the above code you wrote and let me know:
>>>>>>>
>>>>>>> printMinMax(x,True)
>>>>>>> printMinMax(X,True)
>>>>>>>
>>>>>>>
>>>>>>> On Mon, Sep 9, 2019 at 12:18 PM Atul Saini <atulsainimail at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hello Rashed Sir,
>>>>>>>>                            I used dim_sum_n but it could not yield
>>>>>>>> the required result at each grid point. I want to get the sum of the
>>>>>>>> variable through time for all the grid points and therefore I used -
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> *a=addfile("RFIM_1901_1902_days_rf_tym.nc","r")x=a->tym(0:99,:,:)X=dim_sum_n(x,0)*
>>>>>>>> *print(X)*
>>>>>>>>
>>>>>>>> Printing X doesn't provide the correct result. Please guide. Your
>>>>>>>> reply is highly appreciated.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Mon, Sep 9, 2019 at 2:58 PM Rashed Mahmood <
>>>>>>>> rashidcomsis at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> I think you want to use dim_sum_n_wrap() or dim_sum_n() functions
>>>>>>>>> instead of using "sum".  "sum" would result in total of everything for a
>>>>>>>>> variable. See the docs at the following link:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> https://www.ncl.ucar.edu/Document/Functions/Built-in/dim_sum_n.shtml
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Mon, Sep 9, 2019 at 8:55 AM Atul Saini via ncl-talk <
>>>>>>>>> ncl-talk at ucar.edu> wrote:
>>>>>>>>>
>>>>>>>>>> Hi NCL Talk,
>>>>>>>>>>                     I am trying to calculate the value for each
>>>>>>>>>> grid using the function as explained in the script, but at the end the
>>>>>>>>>> result is one value only. I want the value at each grid point.
>>>>>>>>>> *Script is as follows and datafile is attached herewith.*
>>>>>>>>>> ;begin
>>>>>>>>>> a=addfile("Data_File.nc","r")
>>>>>>>>>> x=a->tym(0:4,:,:)
>>>>>>>>>> y=a->rf(0:4,:,:)
>>>>>>>>>> v=a->tym(5:9,:,:)
>>>>>>>>>> w=a->rf(5:9,:,:)
>>>>>>>>>> A1=
>>>>>>>>>> ((sum(y))*(sum(sqrt(x)))-(sum(x))*(sum(x*y)))/(5*(sum(sqrt(x)))-(sqrt(sum(x))))
>>>>>>>>>> B1=
>>>>>>>>>> (5*(sum(x*y))-(sum(x)*sum(y))/(5*(sum(sqrt(x)))-(sqrt(sum(x)))))
>>>>>>>>>> A2=
>>>>>>>>>> ((sum(w))*(sum(sqrt(v)))-(sum(v))*(sum(v*w)))/(5*(sum(sqrt(v)))-(sqrt(sum(v))))
>>>>>>>>>> B2=
>>>>>>>>>> (5*(sum(v*w))-(sum(v)*sum(w))/(5*(sum(sqrt(v)))-(sqrt(sum(v)))))
>>>>>>>>>> chpOnset = ((A1-A2)/(B2-B1))
>>>>>>>>>> print(chpOnset)
>>>>>>>>>> *Please, help me to find out the mistake I am making. Your reply
>>>>>>>>>> is very important to me. Thanks in advance.*
>>>>>>>>>> Regards,
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
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>>>>>>>>>> ncl-talk at ucar.edu
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>>>>>>>>>
>>>>>>>>>
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