Re: create array of max value in vertical for multi-dimensional array

Like DA, I had trouble understanding the question.

As DA suggested,
http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_max_n.shtml

    x(time,level,lat,lon)
        0 1 2 3

Is this what you want:

   xmax = dim_max_n( x, (/2,3/)) ; (ntim,klev)

   printVarSummary(xmax)

On 1/9/12 11:28 PM, Dave Allured wrote:
> So you are inside a loop over jj, and you want to repeat this
> calculation for each jj? In other words, you want a 2-D result, but
> you want to repeat that 2-D result for the number of time steps?
>
> If so, I think you want this inside the time loop. Note that maxZ will
> be overwritten with new values on each iteration:
>
> dim_level = 1
> maxZ = dim_max_n (x (jj,0:29,:,:), dim_level)
>
> Or perhaps this would be simpler if you are not really trying to
> constrain to the first 30 levels:
>
> dim_level = 1
> maxZ = dim_max_n (x (jj,:,:,:), dim_level)
>
> Reference:
> http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_max_n.shtml
>
> --Dave
>
> On Mon, Jan 9, 2012 at 10:14 PM, Chris Herbster<herbstec@erau.edu> wrote:
>> Hi folks,
>>
>> I may have tried the wrong search terms while looking for this in the
>> archives, but perhaps I can get a quick solution to my quest.
>>
>> I would like to obtain the max value at each horizontal point in a
>> multi-dimensional array for each time.
>>
>> The array is x(time,level,lat,lon) and I am looking for the max value
>> for a given time (set with an index value) for each lat/lon location.
>> Obviously when I use the max function on the array I get a scalar
>> result. I'd like the scalar result for each location in the horizontal.
>>
>> I want to obtain a 2D array out of a 4D array, but I have a loop (on jj)
>> that sets the time element to a specific index. I tried:
>>
>> maxZ(:,:) = max (x (jj,0:29,:,:)
>> where jj is a loop over the 24 hours, the second index is Z, the
>> range I want the max value out of, and the last two are the lat and long
>> index values.
>>
>> That gave an error about maxZ not existing. Is the fix as simple as
>> creating the array with the correct dimensions?
>>
>> Of course when I tried to do this without an index placeholder then maxZ
>> is a scalar and I can't plot that on a map.
>>
>> I'm almost certain there is a way to do this without having nested loops
>> on the x and y variables.
>>
>> Thanks for the help!
>>
>> Chris Herbster
>>
>> --
>>
>> Dr. Christopher G. Herbster
>> Associate Professor
>> Director of Science and Technology
>> for the ERAU Weather Center
>> Applied Aviation Sciences
>> Embry-Riddle Aeronautical Univ.
>> 600 S. Clyde Morris Blvd.
>> Daytona Beach, FL 32114-3900
>>
>> 386.226.6444 Office
>> 386.226.6446 Weather Center
>> http://wx.erau.edu/
>>
>> Schedule at: http://wx.erau.edu/faculty/herbster/Schedules/
>>
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Received on Tue Jan 10 08:42:53 2012