From d597a9809338181f681fe0d5000e09c0e81194ff Mon Sep 17 00:00:00 2001
From: Youli <youlituo@gmail.com>
Date: Thu, 20 Jul 2023 15:25:00 +0200
Subject: [PATCH] implement the object oriented approach to read the pulsar
 Ephemeris

---
 tatpulsar/utils/__init__.py |  1 +
 tatpulsar/utils/readpar.py  | 69 +++++++++++++++++++++++++++++++++++++
 tests/test.par              | 34 ++++++++++++++++++
 3 files changed, 104 insertions(+)
 create mode 100644 tatpulsar/utils/readpar.py
 create mode 100644 tests/test.par

diff --git a/tatpulsar/utils/__init__.py b/tatpulsar/utils/__init__.py
index e69de29..09e9fc3 100644
--- a/tatpulsar/utils/__init__.py
+++ b/tatpulsar/utils/__init__.py
@@ -0,0 +1 @@
+from .readpar import readpar
diff --git a/tatpulsar/utils/readpar.py b/tatpulsar/utils/readpar.py
new file mode 100644
index 0000000..62568b3
--- /dev/null
+++ b/tatpulsar/utils/readpar.py
@@ -0,0 +1,69 @@
+"""
+Class to read the TEMPO2 parameter file (.par)
+
+"""
+import numpy as np
+
+freq_pars = [f'F{int(i)}' for i in range(20)]
+pars_we_care = ['PEPOCH', 'START', 'FINISH', 'PHI0'] +\
+               freq_pars
+
+class readpar:
+    """
+    Class to parse the TEMPO2 parameter file (.par)
+    The parameters in the '.par' file might be capitalized but those parameters
+    stored in this object are case INSENSITIVE (see examples below).
+
+    Example
+    -------
+    >>> eph = readpar('test.par')
+    >>> print("F0 = ", eph.F0.value, eph.f0.value)
+    >>> F0 =  29.636679699921209437
+    >>> print("F0 error = ", eph.F0.error)
+    >>> F0 error =  1.7247236495e-09
+    >>> print("PEPOCH = ", eph.PEPOCH.value)
+    >>> PEPOCH =  58066.18087539147382
+    >>> print("PEPOCH error = ", eph.PEPOCH.error)
+    >>> PEPOCH error =  None
+
+    """
+    def __init__(self, filepath):
+        with open(filepath, 'r') as file:
+            lines = file.readlines()
+
+        for line in lines:
+            parts = line.split()
+            if parts:
+                key = parts[0]
+                values = parts[1:]
+                setattr(self, key, values)
+                setattr(self, key.lower(), values)
+
+        for par in pars_we_care:
+            if hasattr(self, par):
+                value_list = getattr(self, par)
+
+                setattr(self, par, type("timingpar", (object,), {})())
+                setattr(self, par.lower(), type("timingpar", (object,), {})()) # Lower case
+
+                setattr(getattr(self, par), 'value', np.float128(value_list[0]))
+                setattr(getattr(self, par.lower()), 'value', np.float128(value_list[0])) # Lower case
+
+                if len(value_list) == 3:
+                    setattr(getattr(self, par), 'error', np.float128(value_list[2]))
+                    setattr(getattr(self, par.lower()), 'error', np.float128(value_list[2]))
+                else:
+                    setattr(getattr(self, par), 'error', None)
+                    setattr(getattr(self, par.lower()), 'error', None)
+
+if __name__ == "__main__":
+    eph = readpar('../../tests/test.par')
+    print("F0 = ", eph.F0.value)
+    print("F0 error = ", eph.F0.error)
+    print("PEPOCH = ", eph.PEPOCH.value)
+    print("PEPOCH error = ", eph.PEPOCH.error)
+
+    print("F0 = ", eph.f0.value)
+    print("F0 error = ", eph.f0.error)
+    print("PEPOCH = ", eph.pepoch.value)
+    print("PEPOCH error = ", eph.pepoch.error)
diff --git a/tests/test.par b/tests/test.par
new file mode 100644
index 0000000..6431095
--- /dev/null
+++ b/tests/test.par
@@ -0,0 +1,34 @@
+PSRJ           J0534+2200
+RAJ            05:34:31.973                 8.1267817736559476629e-4895
+DECJ           +22:00:52.06                 3.1242079228685550361e-4884
+F0             29.636679699921209437     1  0.00000000172472364950
+F1             -3.6964161189285486447e-10 1  2.1200751036944221771e-14
+F2             -4.4100506357621299713e-18 1  1.3732220303612194014e-19
+F3             8.9920447272833230825e-24 1  4.3488380894326679931e-25
+F4             -8.1618753666848709648e-30 1  5.5557310601785298942e-31
+PEPOCH         58066.180875391473819
+POSEPOCH       54760                        4.2026289288901168828e-4933
+DMEPOCH        54760
+START          58066.177875391477251     1
+FINISH         58116.307778270281737     1
+TZRMJD         58088.399365291575503
+TZRFRQ         1000
+TZRSITE        bat
+TRES           39.799
+EPHVER         5
+CLK            TT(TAI)
+MODE 1
+UNITS          TCB
+TIMEEPH        IF99
+DILATEFREQ     Y
+PLANET_SHAPIRO Y
+T2CMETHOD      IAU2000B
+NE_SW          4.000
+CORRECT_TROPOSPHERE  N
+EPHEM          DE405
+NITS           1
+NTOA           249
+CHI2R          1.5028 241
+JUMP freq 999 1001 -0.0008124159772934 1
+JUMP freq 1999 2001 -1.4639986440894e-05 1
+JUMP NAME LE -0.00088 1 1