set_datetime fails within convert_latlon_arr

[alexchartier]

Describe the bug

Several routines (convert_latlon(), convert_latlon_arr(), likely others) fail on a recent Apple M2 laptop due to c_aacgmv2.set_datetime failing. The issue was present both with pip and commandline install.

To Reproduce
% python3
Python 3.9.6 (default, Apr 30 2025, 02:07:17)
[Clang 17.0.0 (clang-1700.0.13.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

import aacgmv2
import datetime as dt
aacgmv2.convert_latlon_arr(0, 0, 100, dt.datetime(2005, 1, 1))
Traceback (most recent call last):
File "/Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2/wrapper.py", line 379, in convert_latlon_arr
c_aacgmv2.set_datetime(dtime.year, dtime.month, dtime.day, dtime.hour,
RuntimeError: AACGM_v2_SetDateTime returned error code -1

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "", line 1, in
File "/Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2/wrapper.py", line 382, in convert_latlon_arr
raise RuntimeError("cannot set time for {:}: {:}".format(dtime, err))
RuntimeError: cannot set time for 2005-01-01 00:00:00: AACGM_v2_SetDateTime returned error code -1

Desktop (please complete the following information):

• OS: MacOS Sequoia
• Version 15.6.1

[aburrell]

Hi @alexchartier, does the same bug happen if you install using gcc instead of clang?

[aburrell]

You can install with gcc by specifying, for example: CC=/opt/local/bin/gcc-mp-14 pip install aacgmv2

[alexchartier]

I reinstalled as follows, to no avail:
% CC=/opt/homebrew/Cellar/gcc/15.1.0/bin/gcc-15
% echo $CC
/opt/homebrew/Cellar/gcc/15.1.0/bin/gcc-15
% /opt/homebrew/Cellar/gcc/15.1.0/bin/gcc-15 --version
gcc-15 (Homebrew GCC 15.1.0) 15.1.0
Copyright (C) 2025 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

% rm -rf /Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2*
% python3 -m pip install aacgmv2

% python3
Python 3.9.6 (default, Apr 30 2025, 02:07:17)
[Clang 17.0.0 (clang-1700.0.13.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

import aacgmv2; import datetime as dt
aacgmv2.convert_latlon_arr(0, 0, 100, dt.datetime.now())
Traceback (most recent call last):
File "/Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2/wrapper.py", line 379, in convert_latlon_arr
c_aacgmv2.set_datetime(dtime.year, dtime.month, dtime.day, dtime.hour,
RuntimeError: AACGM_v2_SetDateTime returned error code -1

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "", line 1, in
File "/Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2/wrapper.py", line 382, in convert_latlon_arr
raise RuntimeError("cannot set time for {:}: {:}".format(dtime, err))
RuntimeError: cannot set time for 2025-09-09 10:39:05.662869: AACGM_v2_SetDateTime returned error code -1

[aburrell]

Thanks for helping debug. However, pip is really bad about ignoring environment variables. You have to alter the install line to specify GCC. Now that you have gcc installed, try: CC=/opt/homebrew/Cellar/gcc/15.1.0/bin/gcc-15 python3 -m pip install aacgmv2.

[alexchartier]

No effect from that:
% rm -rf /Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2*
% CC=/opt/homebrew/Cellar/gcc/15.1.0/bin/gcc-15 python3 -m pip install aacgmv2
Defaulting to user installation because normal site-packages is not writeable
Collecting aacgmv2
Using cached aacgmv2-2.7.0-cp39-cp39-macosx_10_9_universal2.whl
Installing collected packages: aacgmv2
Successfully installed aacgmv2-2.7.0

% python3
Python 3.9.6 (default, Apr 30 2025, 02:07:17)
[Clang 17.0.0 (clang-1700.0.13.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.

import aacgmv2; import datetime as dt
aacgmv2.convert_latlon_arr(0, 0, 100, dt.datetime.now())
Traceback (most recent call last):
File "/Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2/wrapper.py", line 379, in convert_latlon_arr
c_aacgmv2.set_datetime(dtime.year, dtime.month, dtime.day, dtime.hour,
RuntimeError: AACGM_v2_SetDateTime returned error code -1

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "", line 1, in
File "/Users/chartat1/Library/Python/3.9/lib/python/site-packages/aacgmv2/wrapper.py", line 382, in convert_latlon_arr
raise RuntimeError("cannot set time for {:}: {:}".format(dtime, err))
RuntimeError: cannot set time for 2025-09-09 11:41:34.654660: AACGM_v2_SetDateTime returned error code -1

[aburrell]

Ok. I'll have to figure out a way to test this, since I don't have access to the Apple M2 system. Does the C-code for AACGMV2 work for you (outside of Python)? That would help narrow down if it's a problem with the C-code or the C-to-Python interface.

[alexchartier]

My previous M2 system ran this code without issues, so I'm not sure it's an M2-wide issue. Can you recommend a test procedure for the C code?

[aburrell]

I have the same OS as you, but on Intel and running Python 3.10, and it runs. You could try upping the Python version to reduce variation, but it doesn't look like that type of error.

Ok, here's the website with the code: https://superdarn.thayer.dartmouth.edu/aacgm.html

Download the code, untar it, and enter the program directory. Then follow the readme by building the internal test program:
gcc -o test_aacgm test_aacgm.c aacgmlib_v2.c igrflib.c astalglib.c mlt_v2.c rtime.c -lm

And then run it as ./test_aacgm:

I get the output:

================================================================================

AACGM-v2 Test Program

================================================================================

TEST: no date/time (this will return an error.)

**************************************************************************
* AACGM-v2 ERROR: No Date/Time Set                                       *
*                                                                        *
* You must specifiy the date and time in order to use AACGM coordinates, *
* which depend on the internal (IGRF) magnetic field. Before calling     *
* AACGM_v2_Convert() you must set the date and time to the integer values*
* using the function:                                                    *
*                                                                        *
*   AACGM_v2_SetDateTime(year,month,day,hour,minute,second);             *
*                                                                        *
* or to the current computer time in UT using the function:              *
*                                                                        *
*   AACGM_v2_SetNow();                                                   *
*                                                                        *
* subsequent calls to AACGM_v2_Convert() will use the last date and time *
* that was set, so update to the actual date and time that is desired.   *
**************************************************************************

TEST: Setting time to : 20290322 0311:00

TEST: geographic to AACGM-v2
     GLAT       GLON        HEIGHT       MLAT       MLON       R
     45.500000  -23.500000  1135.000000  47.402897  56.602300  1.177533

TEST: AACGM-v2 to geographic
     MLAT       MLON        HEIGHT       GLAT       GLON       HEIGHT
     47.402897  56.602300  1131.097495  45.439863  -23.477496  1134.977555

Do the same thing but use field-line tracing

TEST: geographic to AACGM-v2 (TRACE)
     GLAT       GLON        HEIGHT       MLAT       MLON       R
     45.500000  -23.500000  1135.000000  47.408678  56.600154  1.177533

TEST: AACGM-v2 to geographic (TRACE)
     MLAT       MLON        HEIGHT       GLAT       GLON       HEIGHT
     47.408678  56.600154  1131.097495  45.500001  -23.500000  1135.000000

--------------------------------------------------------------------------------

Testing MLT
--------------------------------------------------------------------------------

      GLAT       GLON        HEIGHT       MLAT       MLON       MLT
TRACE 37.000000  -88.000000  300.000000  48.839634  -17.004932  1.977822
COEFF 37.000000  -88.000000  300.000000  48.844360  -16.999467  1.978187


Array:
      45.0000   0.0000    150.0000     40.2851     76.6686      8.2227
      45.0000   1.0000    150.0000     40.2456     77.4908      8.2775
      45.0000   2.0000    150.0000     40.2116     78.3166      8.3326
      45.0000   3.0000    150.0000     40.1830     79.1461      8.3879
      45.0000   4.0000    150.0000     40.1594     79.9794      8.4434
      45.0000   5.0000    150.0000     40.1407     80.8166      8.4993
      45.0000   6.0000    150.0000     40.1267     81.6577      8.5553
      45.0000   7.0000    150.0000     40.1171     82.5029      8.6117
      45.0000   8.0000    150.0000     40.1116     83.3521      8.6683
      45.0000   9.0000    150.0000     40.1102     84.2055      8.7252
      45.0000  10.0000    150.0000     40.1125     85.0631      8.7824
      45.0000  11.0000    150.0000     40.1184     85.9250      8.8398
      45.0000  12.0000    150.0000     40.1275     86.7910      8.8976
      45.0000  13.0000    150.0000     40.1398     87.6614      8.9556
      45.0000  14.0000    150.0000     40.1550     88.5360      9.0139
      45.0000  15.0000    150.0000     40.1730     89.4149      9.0725
      45.0000  16.0000    150.0000     40.1934     90.2981      9.1314
      45.0000  17.0000    150.0000     40.2161     91.1856      9.1905
      45.0000  18.0000    150.0000     40.2409     92.0774      9.2500
      45.0000  19.0000    150.0000     40.2677     92.9734      9.3097

[alexchartier]

OK test failed due to AACGM time not set:

TEST: no date/time (this will return an error.)

---

• AACGM-v2 ERROR: No Date/Time Set *

•                                                                    *
  

• You must specifiy the date and time in order to use AACGM coordinates, *
• which depend on the internal (IGRF) magnetic field. Before calling *
• AACGM_v2_Convert() you must set the date and time to the integer values*
• using the function: *

•                                                                    *
  

• AACGM_v2_SetDateTime(year,month,day,hour,minute,second); *

•                                                                    *
  

• or to the current computer time in UT using the function: *

•                                                                    *
  

• AACGM_v2_SetNow(); *

•                                                                    *
  

• subsequent calls to AACGM_v2_Convert() will use the last date and time *
• that was set, so update to the actual date and time that is desired. *

---

TEST: Setting time to : 20290322 0311:00

zsh: segmentation fault ./test_aacgm

Looks like this is to be expected now (maybe a recent change?). From the AACGM readme:

3. New user-space functions have been added that allow users to set the
   date and time. The functions are:

   AACGM_v2_SetDateTime(int year, int month, int day, int hour,
                    int minute, int second);
   
   AACGM_v2_SetNow();
   

   The latter will use the current computer date and time in UT.

   Note that setting the time frequently triggers an interpolation in time and
   in altitude, which will slow the calculations. Testing should be done to
   determine what the correspondence between changes in time and AACGM lat/lon
   are.

4. You must set the date and time at least once or the code will not run.

The test program does not actually invoke ..SetNow() anywhere, but it does use SetDateTime()

[aburrell]

It's "new" as of several versions ago, the readme just kept that bit around.

Since this is a problem with the C code, you may be able to get Simon Shepherd to debug it, or could also corral the RST team. I'll still try and track down a suitable machine for testing, though. Very helpful to know the issue is with the C code base.

[alexchartier]

OK yes looking closer at the C code, it seg-faults when it tries to set the time.