# [ncl-talk] Wondering why I am getting this dimensions error

Rashed Mahmood rashidcomsis at gmail.com
Wed Nov 27 11:58:40 MST 2019

``` Sorry for chipping in here, and may be I am wrong but I do not follow the
logic:

If you do: sum_q :=  where(qs(k,:,:).ge.0.1,sum_q+1,sum_q)

The variable "sum_q" would be a 2d array containing *2s* and *1s*. Do you
want a sum of 2s and 1s or you want a sum of qs(k,:,:) where it is greater
than 0.1?

On Wed, Nov 27, 2019 at 10:50 AM Barry Lynn via ncl-talk <ncl-talk at ucar.edu>
wrote:

> Hi:
>
> The problem with the previous suggestion was that the sum_q became a 2
> dimensional variable..  I needed it to be a 1D variables. I found this out
> by using the "function" printVarSummary
>
> Here is the correct solution for my needs, based on the very helpful
>
> Thanks
>
> (sum_q was defined as a 2d variable -- note: sum_q is not really a sum, as
> used here, but defined as 1 whereever qs > 0.1).
>
>        sum_q = 0
>
>        sum_q(0,0) = 1 ; just so I don't divide by 0!
>
>        sum_q =  where(qs(k,:,:).ge.0.1,sum_q+1,sum_q)
>
>        add_q = sum(sum_q); a 1d variable
>
>  ;      printVarSummary(qs_1(k))
>
>   ;     printVarSummary(sum_q)
>
>
>
> On Wed, Nov 27, 2019 at 8:18 PM Dennis Shea <shea at ucar.edu> wrote:
>
>> re:   :=
>> Yes.
>>
>> On Wed, Nov 27, 2019 at 10:49 AM Barry Lynn via ncl-talk <
>> ncl-talk at ucar.edu> wrote:
>>
>>> Hi Dave:
>>>
>>> Thank you for your suggestions.
>>>
>>> I actually need to sum_q for all elements of the remaining (:,:) 2d
>>> array to obtain a single number.
>>>
>>> I am dividing one number by it.
>>>
>>> I assume that it is okay to put the := and that I will get the sum over
>>> all 2d elements?
>>>
>>> On Wed, Nov 27, 2019 at 7:40 PM Dave Allured - NOAA Affiliate <
>>> dave.allured at noaa.gov> wrote:
>>>
>>>> "sum_q = 1." defines this variable as scalar.  Then the where statement
>>>> attempts to write a 2-D array onto a scalar.  The assignment statement is
>>>> not allowed to change dimensions.
>>>>
>>>> One way to fix this would be to use the reassignment operator ":=",
>>>> which IS allowed to change dimensions on assignment.
>>>>
>>>> Another way to fix this would be to define sum_q as a 2-D array before
>>>> the start of the loop.  I suspect that is what you really intended.
>>>>
>>>>
>>>> On Wed, Nov 27, 2019 at 10:22 AM Barry Lynn via ncl-talk <
>>>> ncl-talk at ucar.edu> wrote:
>>>>
>>>>> Hi:
>>>>>
>>>>> I have some simple code.
>>>>>
>>>>>       do k = 0,dims3d(0)-1
>>>>>
>>>>>        qs(k,:,:) = where(qs(k,:,:).lt.0.1,q_null(k,:,:),qs(k,:,:))
>>>>>
>>>>>        sum_q = 1.
>>>>>
>>>>>        sum_q =  where(qs(k,:,:).ge.0.1,sum_q+1,sum_q)
>>>>>
>>>>>        qs_1(k) = sum(qs(k,:,:))/sum_q+qs_1(k)
>>>>>
>>>>>       end do
>>>>>
>>>>>
>>>>> Why can't I do the "where" sum?
>>>>>
>>>>>
>>>>> fatal:Number of dimensions on right hand side do not match number of
>>>>> dimension in left hand side
>>>>>
>>>>> --
>>>>> Barry H. Lynn, Ph.D
>>>>> Senior Associate Scientist, Lecturer,
>>>>> The Institute of the Earth Science,
>>>>> The Hebrew University of Jerusalem,
>>>>> Givat Ram, Jerusalem 91904, Israel
>>>>> Tel: 972 547 231 170
>>>>> Fax: (972)-25662581
>>>>>
>>>>> C.E.O, Weather It Is, LTD
>>>>> Weather and Climate Focus
>>>>> http://weather-it-is.com
>>>>> Jerusalem, Israel
>>>>> Local: 02 930 9525
>>>>> Cell: 054 7 231 170
>>>>> Int-IS: x972 2 930 9525
>>>>>
>>>>
>>>
>>> --
>>> Barry H. Lynn, Ph.D
>>> Senior Associate Scientist, Lecturer,
>>> The Institute of the Earth Science,
>>> The Hebrew University of Jerusalem,
>>> Givat Ram, Jerusalem 91904, Israel
>>> Tel: 972 547 231 170
>>> Fax: (972)-25662581
>>>
>>> C.E.O, Weather It Is, LTD
>>> Weather and Climate Focus
>>> http://weather-it-is.com
>>> Jerusalem, Israel
>>> Local: 02 930 9525
>>> Cell: 054 7 231 170
>>> Int-IS: x972 2 930 9525
>>>
>>> _______________________________________________
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>>
>>
>
> --
> Barry H. Lynn, Ph.D
> Senior Associate Scientist, Lecturer,
> The Institute of the Earth Science,
> The Hebrew University of Jerusalem,
> Givat Ram, Jerusalem 91904, Israel
> Tel: 972 547 231 170
> Fax: (972)-25662581
>
> C.E.O, Weather It Is, LTD
> Weather and Climate Focus
> http://weather-it-is.com
> Jerusalem, Israel
> Local: 02 930 9525
> Cell: 054 7 231 170
> Int-IS: x972 2 930 9525
>
> _______________________________________________
> ncl-talk mailing list
> ncl-talk at ucar.edu
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
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