[ncl-talk] avoiding loops

[Micah Sklut]

Instead of sending output to a file, is it possible to do a write_matrix
formatting to 1d array?  I need to add more than 1 of these variables
together, so if I can create 1d arrays for all of the variables and
metadata, such as lat/lon, then I can use write_table to join everything
together. When I'm re-ordering or reshaping the arrays, I'll just need to
delete the old arrays, to free up memory.

On Sun, Sep 22, 2019 at 1:51 PM Dave Allured - NOAA Affiliate <
dave.allured at noaa.gov> wrote:

> There is a mistake in the untested example that I sent.  Please change the
> format spec from "384(f0.1,','),f0.1" to "383(f0.1,','),f0.1".  The latter
> is correct for 384 numbers per line.  I split the format spec into two
> parts so that there would not be a trailing comma at the end of each line.
>
> Generally speaking, the format spec in write_matrix is specified for a
> single output line.  It is repeated for each output line.  It is important
> that the total item count in the format spec (383 + 1 in this case) exactly
> matches the intended number of items per line.
>
>
> On Sun, Sep 22, 2019 at 11:32 AM Micah Sklut <micahs2005 at gmail.com> wrote:
>
>> Okay, thanks, Dave.  That sounds like what I need. I've always struggled
>> with the formatting in NCL, but I'll give that a go and see where I get.
>>
>> On Sun, Sep 22, 2019 at 1:26 PM Dave Allured - NOAA Affiliate <
>> dave.allured at noaa.gov> wrote:
>>
>>> Try write_matrix and the F0 format descriptor.  F0 format is part of
>>> fortran 90 and up.  It is described in modern fortran documentation.  It is
>>> like the common Fw.d format descriptor, except leading blanks to the left
>>> of the decimal point are suppressed.
>>>
>>> Reshape your array from, e.g. (lat,lon,time), to a 2-D array in the
>>> desired output order, (points,time).  Npoints = Nlats x Nlons.  Then a
>>> single call to write_matrix should write the entire output file:
>>>
>>>     opt = True
>>>     opt at fout = "temperature.csv"
>>>     write_matrix (data_out, "384(f0.1,','),f0.1", opt)
>>>
>>> You can add arbitrary extra numeric columns to the output array, if it
>>> would be helpful to have lats and lons, or other such metadata, on each
>>> line of output.
>>>
>>>
>>> On Sat, Sep 21, 2019 at 2:53 PM Micah Sklut via ncl-talk <
>>> ncl-talk at ucar.edu> wrote:
>>>
>>>> Hi,
>>>>
>>>> I have a task to take GFS data and concatenate variables across all the
>>>> forecast hours, for each grid point.
>>>>
>>>> For example, taking a temperature variable for each grid point, for all
>>>> latitude and longitudes, and creating a string that represents the values
>>>> for each forecast hour.
>>>> So, if we have for latitude y, and longitude x, there would be a string
>>>> value like "70.5,71.5,71.5,72.0,...nHours".  The end product will be a line
>>>> for each grid point for the variables i"m looking at that will be written
>>>> to a file to be imported into a database.
>>>>
>>>> Creating loops through all hours, latitudes, and longitudes will get
>>>> the job done, but is expensive and was looking to see if there were any NCL
>>>> functions that would help here.
>>>>
>>>> Thank you.
>>>>
>>>

-- 
Micah Sklut
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