[ncl-talk] Crash with eofunc_varimax_Wrap function

[Dennis Shea]

offline from ncl-talk

re my comment:

I am not sure why you want to rotate.
The 1st two modes look very distinct.

===

Deriving a "global" eof is rather unusual for ocean grids. The atmosphere
is 'continuous'. The oceans are 'discontinuous' due to the continents. The
EOFs may be though of as orthogonal structures that result from
covariances.  Deriving a 'global' EOF is implicitly 'saying' that SST
variations in the Kuroshio may be related to the Gulf Stream.

An Example of using an EOF analysis over the ocean is:

http://www.ncl.ucar.edu/Applications/eof.shtml
Example 3

Good Luck



On Wed, Jun 29, 2016 at 4:17 PM, Dennis Shea <shea at ucar.edu> wrote:

> Hi Allison,
>
> Can you please try the attached?
>
> I am not sure why you want to rotate.
> The 1st two modes look very distinct.
>
> I did not plot anything. I'll let that to you
>
>
> THX
> D
>
> On Tue, Jun 28, 2016 at 8:07 AM, Allison Serakos <sera0021 at umn.edu> wrote:
>
>> script name: ncl-talk_reof.ncl
>> data file name: HadISST_sst.nc.gz
>>
>> Thank you,
>> Allison
>>
>> On Mon, Jun 27, 2016 at 1:49 PM, Allison Serakos <sera0021 at umn.edu>
>> wrote:
>>
>>> Hello,
>>>
>>>
>>>
>>> I am using the eofunc_varimax_Wrap function to analyze global rotated
>>> EOFs produced from the eofunc_Wrap function. However, when I run my script,
>>> it hangs when it reaches the eofunc_varimax_Wrap function. The script does
>>> not finish and I get no error message.
>>>
>>>
>>>
>>> The dataset that I am using is the HadISST 1.1 monthly average sea
>>> surface temperature dataset. It is a 3-dimensional (time, latitude,
>>> longitude) global 1° x 1° grid dataset with 1755 time values, 180
>>> latitude, and 360 longitude. I produce annually averaged values and
>>> spatially weighted it prior to the EOF analysis.
>>>
>>>
>>>
>>> I have been using a Mac machine with NCL version 6.3.0 and a Linux
>>> machine with NCL version 6.2.1 and the program hangs when conducting the
>>> rotation.
>>>
>>>
>>>
>>> I tried running the script with global data for different time periods
>>> (all between 113 and 102 years of global data) on both the Mac and Linux
>>> machines and found that the function works only for some time periods
>>> and crashes with others. These periods differ between the two Mac and Linux
>>> machines that I used. I also tried reshaping the data from a 3D matrix
>>> to a 2D matrix using the reshape function and combining the spatial
>>> components. In this situation, the rotation output was still the same as
>>> above for the respective time periods and machines. Additionally, I tried
>>> reducing the spatial domain and found that when I reduce the latitude range
>>> (anything smaller than 69S-90N) for any time period the script runs on
>>> both machines and the function does not crash.
>>>
>>>
>>>
>>> I used ‘ncl –x’ to see if there is an error in my script, but the script
>>> only crashes before the eofunc_varimax_Warp function with no messages. When
>>> I run the script, NCL uses about 592.5MB of the 12GB of memory on the Mac
>>> machine, so I do not believe this an issue of lack of memory space.
>>>
>>>
>>>
>>> I am wondering if there is a known problem with the eofunc_varimax_Wrap
>>> function? I am also wondering if you have any thoughts as to why the
>>> function may be crashing under certain situations and not others?
>>>
>>>
>>>
>>> Here is a copy of my EOF and Varimax Rotation script:
>>>
>>> ;----------------------------------------------------------------
>>>
>>> ;***** EOF *****
>>>
>>> neval = 6
>>>
>>> optEOF = True
>>>
>>> optEOF at method = "transpose"
>>>
>>> optEOF at jopt = 0
>>>
>>>
>>>
>>> eof = eofunc_Wrap(av,neval,optEOF)
>>>
>>>
>>>
>>> ;***** VARIMAX ROTATION *****
>>>
>>> eof_rot = eofunc_varimax_Wrap(eof,-1)
>>>
>>> eof_varimax_reorder(eof_rot)
>>>
>>> ;----------------------------------------------------------------
>>>
>>>
>>>
>>> Thanks for your help in advance.
>>>
>>>
>>>
>>> Kind regards,
>>>
>>> Allison
>>>
>>>
>>> --
>>> Allison Serakos
>>> Graduate Research Assistant
>>> Department of Soil, Water, and Climate
>>> University of Minnesota
>>> 1991 Upper Buford Circle, Rm S535
>>> St. Paul, MN 55108
>>>
>>
>>
>>
>> --
>> Allison Serakos
>> Graduate Research Assistant
>> Department of Soil, Water, and Climate
>> University of Minnesota
>> 1991 Upper Buford Circle, Rm S535
>> St. Paul, MN 55108
>>
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