We wrote a C software python library to read PAS calibration files.

Download python library

Requirements

The PAS calibration python library needs :

  • a valid gcc compiler

  • python 3.x version 3.4 or greater

  • numpy installed for that python release

  • spacepy/pycdf library to read CDF files (not mandatory)

Installation

Download and extract sources

Download the pas-calib.1.0.tar.gz in a given directory.

Extract source :

$ tar xvzf pas-calib.v1.0.tar.gz

You will get the following directory tree :

  • pas-calib.1.0/profile : definition of some environment variables

  • pas-calib.1.0/build : script to build python library

  • pas-calib.1.0/tools : low-level C tools library

  • pas-calib.1.0/calib : low-level C library used to read and parse PAS calibration files

  • pas-calib.1.0/calib/python : Python C API used to read calibration from python

Environment profile

Use pas-calib.1.0/profile to set some environment variable to use python calibration library :

  • PYTHONPATH : needed by python to find directory where calibration library is installed

  • CALIB_DIR : needed to find directory where calibration files are installed 

$ cd pas-calib.1.0
$ . profile

Build library

Run the build script :

$ cd pas-calib.1.0
$ . profile
$ ./build

That will generates and test the python calibration library.

The test script is located on :

pas-calib.1.0/calib/python/test_calib.py

It is run automatically after build process, and should display something like :

Logfile : calib.log
Calibrations for 2020-06-26T16:53:54
Azimuths : [-21.673     -14.561501   -8.610001   -2.7020001   3.1375      9.018499
  14.91       20.663      27.381      33.321      39.103    ]
Elevations : [-17.082      -13.976      -10.379       -6.0695      -0.51549995
   5.2869997   10.726999    15.2095      19.874     ]
Energies : [18450.5      17398.822    16407.09     15471.888    14589.988
 13758.356    12974.129    12234.612    11537.236    10879.615
 10259.478     9674.685     9123.228     8603.206     8112.822
  7650.391     7214.3184    6803.106     6415.328     6049.6553
  5704.8237    5379.649     5073.0107    4783.85      4511.1675
  4254.0283    4011.5527    3782.896     3567.269     3363.9368
  3172.194     2991.377     2820.8655    2660.0747    2508.4497
  2365.4714    2230.6394    2103.4893    1983.591     1870.5297
  1763.9104    1663.3638    1568.5496    1479.1431    1394.8345
  1315.3286    1240.3561    1169.6562    1102.9851    1040.1171
   980.8327     924.9216     872.1995     822.48584    775.60095
   731.3901     689.70306    650.3899     613.3159     578.3611
   545.3951     514.3035     484.99127    457.348      431.27936
   406.69476    383.5099     361.64926    341.03827    321.60147
   303.2694     285.9818     269.67886    254.31061    239.8167
   226.14255    213.25328    201.09833    189.63336    178.8281
   168.63736    159.02144    149.95546    141.40912    133.34755
   125.74587    118.57895    111.82191    105.44959     99.43713
    93.769684    88.42693     83.38402     78.631226    74.15311
    69.92481 ]

Installation notes

The python library will be generated in user directory, generally :

${HOME}/.local/lib/python3.6/site-package

You can find the directory corresponding to your python release with :

$ python -m site --user-site
Caution This directory has to be added in the PYTHONPATH environment variable (done by the environment profile).

User manual

Import library

$ python
>>> import calib
Logfile : calib.log

Low-level calibration messages or errors are stored in calib.log, in current directory.

Getting help

>>>> help(calib)
Help on module calib:

NAME
    calib - Solar Orbiter Calibration library

FUNCTIONS
    catalog(...)
        catalog() -- return calibration catalog filename

    init(...)
        init() -- Initialise calibration catalog

    read(...)
        read(datetime, key) -- return numpy array

    test(...)
        test() -- test purpose function

FILE
    /home/solar/.local/lib/python3.6/site-packages/calib.cpython-36m-x86_64-linux-gnu.so

Getting calibration data

You must use the calib.read (datetime, key) function, with 2 parameters :

  • datetime : a valid python datetime object (calibration files could change)

  • key : a valid calibration key, corresponding to keys found in calibration catalalog.

If return a numpy array (or record-array), depending on the key type

Valid keys are :

  • AZS : Azimuth simplified table

  • AZF : Azimuth full table

  • ELS : Elevation simplified table

  • ELF : Elevation full table

  • EVS : Energy simplifier table

  • EVF : Energy full table

  • CNF : Moment correction coefficients

  • GFF : geometrical factors

  • etc…

Read calibration catalog to get a full list of allowed calibration keys.

Exemple
>>> from datetime import *
>>> now = datetime.now()
>>> azs = calib.read (now, "AZS")
>>> gff = calib.read (now, "GFF")

Azimuth or Elevation tables

Return value is a numpy record array, with a given shape and a given dtype, that contains:

  • amin : angle bin min value

  • amoy : angle bin median value

  • amax : angle bin max value

  • sin : sin of median angle value

  • cos : cos of median angle value

Exemple
>>>> azs = calib.read (now, "AZS")
>>> azs.shape
(11,)
>>> azs.dtype
dtype((numpy.record, [('amin', '<f4'), ('amoy', '<f4'), ('amax', '<f4'), ('sin', '<f4'), ('cos', '<f4')]))

>>> azf = calib.read (now,"AZF")
>>> azf.shape
(11, 9)
>>> azf.dtype
dtype((numpy.record, [('amin', '<f4'), ('amoy', '<f4'), ('amax', '<f4'), ('sin', '<f4'), ('cos', '<f4')]))

You can get amin, amoy, amax, sin of cos field name, for a single azimuth, whole table, or sub-set.

Exemple of use
# Get Azimtuths median values
>>> azs.amoy
array([-21.673    , -14.561501 ,  -8.610001 ,  -2.7020001,   3.1375   ,
         9.018499 ,  14.91     ,  20.663    ,  27.381    ,  33.321    ,
        39.103    ], dtype=float32)
# Get given Azimuth values
>>> azs[2].moy
-8.610001

# Get all fields for a given azimuth
>>> azs [0]
(-25.229, -21.673, -18.117, -0.3693089, 0.9293067)

Energy tables

Return value is a numpy record array, with a given shape and a given dtype, that contains:

  • emin : energy bin min value

  • emoy : energy bin median value

  • emax : energy bin max value

Exemple
>>> evs = calib.read(now,"EVS")
>>> evs.shape
(96,)
>>> evs.dtype
dtype((numpy.record, [('emin', '<f4'), ('emoy', '<f4'), ('emax', '<f4')]))
>>> evf = calib.read(now,"EVF")
>>> evf.shape
(11, 9, 96)
>>> evf.dtype
dtype((numpy.record, [('emin', '<f4'), ('emoy', '<f4'), ('emax', '<f4')]))

You can get, emin, emoy or emax values, for a single, sub-set or whole energy bins.

>>> evs.emoy
>>> evs [0]
>>> evs.emoy [67]
>>> evs.emoy [0:16]

Other calibration tables

Other calibration tables are normal numpy array, with a given shape and dtype = float32

Exemple
>>> cnf = calib.read(now,"CNF")
>>> cnf.shape
(11, 9, 96)
>>> yil = calib.read(now,"YIL")
>>> yil.shape
(11, 9, 11, 9)
>>> yil.dtype
dtype('float32')