[ncl-talk] avoiding loops

Mon Sep 23 11:31:24 MDT 2019

Fortran 90+ also has I0 format to suppress leading zeros on integers.  Use
that with integer data for this application.

Floattointeger will not convert to integer if you assign the result to a
pre-existing float variable.  Try assigning the result to a new variable
not previously defined, or a previously defined variable of type integer.
Use printVarSummary to confirm.

I think you could also use floattointeger in-line within the write_matrix
procedure call, and save a little memory that way.

On Mon, Sep 23, 2019 at 11:00 AM Micah Sklut <micahs2005 at gmail.com> wrote:

> NCL wont allow me to use i5 format on the variable. I've used the
> floattointeger, but when I print that variable, it still shows that is of
> type float, even though the values were properly converted to integer.
>
> On Mon, Sep 23, 2019 at 12:57 PM Dennis Shea <shea at ucar.edu> wrote:
>
>> *  fmtf*
>>
>> Format to be used, specified *via Fortran style*. The format string used
>> must agree with the variable type.
>>
>> ===
>>
>> Google fortran edit descriptors..
>>
>> "384(f0.1,','),f0.1"
>>
>> "384(i5,','),i5"
>>
>> On Mon, Sep 23, 2019 at 12:43 PM Micah Sklut via ncl-talk <
>> ncl-talk at ucar.edu> wrote:
>>
>>> This worked great Dave. I appreciate the great support. I did the
>>> asciiread to read back in all the string arrays, and then used write_table
>>> to format the final output.
>>>
>>> One last question. When formating the write_matrix calls, I'm trying to
>>> write a float variable to integer format.  When I use, floattointeger
>>> function, it properly converts the values to integers, however, it doesn't
>>> change the variable type in the metadata from float to integer. This
>>> doesn't allow me to write_matrix using integer format. Is there an easy way
>>> to get around this?
>>>
>>> On Sun, Sep 22, 2019 at 8:31 PM Dave Allured - NOAA Affiliate <
>>> dave.allured at noaa.gov> wrote:
>>>
>>>> Write_matrix is strictly for output to only a text file, or Unix
>>>> standard output.  There is no internal write capability.  However, you can
>>>> simulate internal writes by using one or more temporary files.
>>>>
>>>> Read the formatted lines back in from a temp file with asciiread
>>>> ("tmp.txt", -1, "string").  This gives you a 1-D array of strings, one full
>>>> line for each of your grid points.  Then repeat for each of your other
>>>> variables.  This will efficiently give you arrays of full formatted line
>>>> strings for several variables.
>>>>
>>>> You should then be able to join these line strings together, however
>>>> you have in mind.  Also, now that you are operating on strings, you can add
>>>> text columns at the beginning or end of each string, if this would be of
>>>> any help.  For example:
>>>>
>>>> long_lines = "precip," + p_lines(:) + ",Tmin," + tmin_lines(:) +
>>>> ",Tmax," + tmax_lines(:)
>>>>
>>>> This example is for joining horizontally.  You could also join
>>>> vertically by simply joining the string arrays, with or without
>>>> interleaving.  There are many variations on this theme, depending on how
>>>> you want your final output to be structured.
>>>>
>>>>
>>>> On Sun, Sep 22, 2019 at 5:29 PM Micah Sklut <micahs2005 at gmail.com>
>>>> wrote:
>>>>
>>>>> 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.
>>>>>>>>>
>>>>>>>>
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