212 lines
6.0 KiB
Python
212 lines
6.0 KiB
Python
"""Epoch module."""
|
|
|
|
import functools
|
|
import operator
|
|
import math
|
|
import datetime as DT
|
|
|
|
from matplotlib import _api
|
|
from matplotlib.dates import date2num
|
|
|
|
|
|
class Epoch:
|
|
# Frame conversion offsets in seconds
|
|
# t(TO) = t(FROM) + allowed[ FROM ][ TO ]
|
|
allowed = {
|
|
"ET": {
|
|
"UTC": +64.1839,
|
|
},
|
|
"UTC": {
|
|
"ET": -64.1839,
|
|
},
|
|
}
|
|
|
|
def __init__(self, frame, sec=None, jd=None, daynum=None, dt=None):
|
|
"""
|
|
Create a new Epoch object.
|
|
|
|
Build an epoch 1 of 2 ways:
|
|
|
|
Using seconds past a Julian date:
|
|
# Epoch('ET', sec=1e8, jd=2451545)
|
|
|
|
or using a matplotlib day number
|
|
# Epoch('ET', daynum=730119.5)
|
|
|
|
= ERROR CONDITIONS
|
|
- If the input units are not in the allowed list, an error is thrown.
|
|
|
|
= INPUT VARIABLES
|
|
- frame The frame of the epoch. Must be 'ET' or 'UTC'
|
|
- sec The number of seconds past the input JD.
|
|
- jd The Julian date of the epoch.
|
|
- daynum The matplotlib day number of the epoch.
|
|
- dt A python datetime instance.
|
|
"""
|
|
if ((sec is None and jd is not None) or
|
|
(sec is not None and jd is None) or
|
|
(daynum is not None and
|
|
(sec is not None or jd is not None)) or
|
|
(daynum is None and dt is None and
|
|
(sec is None or jd is None)) or
|
|
(daynum is not None and dt is not None) or
|
|
(dt is not None and (sec is not None or jd is not None)) or
|
|
((dt is not None) and not isinstance(dt, DT.datetime))):
|
|
raise ValueError(
|
|
"Invalid inputs. Must enter sec and jd together, "
|
|
"daynum by itself, or dt (must be a python datetime).\n"
|
|
"Sec = %s\n"
|
|
"JD = %s\n"
|
|
"dnum= %s\n"
|
|
"dt = %s" % (sec, jd, daynum, dt))
|
|
|
|
_api.check_in_list(self.allowed, frame=frame)
|
|
self._frame = frame
|
|
|
|
if dt is not None:
|
|
daynum = date2num(dt)
|
|
|
|
if daynum is not None:
|
|
# 1-JAN-0001 in JD = 1721425.5
|
|
jd = float(daynum) + 1721425.5
|
|
self._jd = math.floor(jd)
|
|
self._seconds = (jd - self._jd) * 86400.0
|
|
|
|
else:
|
|
self._seconds = float(sec)
|
|
self._jd = float(jd)
|
|
|
|
# Resolve seconds down to [ 0, 86400)
|
|
deltaDays = math.floor(self._seconds / 86400)
|
|
self._jd += deltaDays
|
|
self._seconds -= deltaDays * 86400.0
|
|
|
|
def convert(self, frame):
|
|
if self._frame == frame:
|
|
return self
|
|
|
|
offset = self.allowed[self._frame][frame]
|
|
|
|
return Epoch(frame, self._seconds + offset, self._jd)
|
|
|
|
def frame(self):
|
|
return self._frame
|
|
|
|
def julianDate(self, frame):
|
|
t = self
|
|
if frame != self._frame:
|
|
t = self.convert(frame)
|
|
|
|
return t._jd + t._seconds / 86400.0
|
|
|
|
def secondsPast(self, frame, jd):
|
|
t = self
|
|
if frame != self._frame:
|
|
t = self.convert(frame)
|
|
|
|
delta = t._jd - jd
|
|
return t._seconds + delta * 86400
|
|
|
|
def _cmp(self, op, rhs):
|
|
"""Compare Epochs *self* and *rhs* using operator *op*."""
|
|
t = self
|
|
if self._frame != rhs._frame:
|
|
t = self.convert(rhs._frame)
|
|
if t._jd != rhs._jd:
|
|
return op(t._jd, rhs._jd)
|
|
return op(t._seconds, rhs._seconds)
|
|
|
|
__eq__ = functools.partialmethod(_cmp, operator.eq)
|
|
__ne__ = functools.partialmethod(_cmp, operator.ne)
|
|
__lt__ = functools.partialmethod(_cmp, operator.lt)
|
|
__le__ = functools.partialmethod(_cmp, operator.le)
|
|
__gt__ = functools.partialmethod(_cmp, operator.gt)
|
|
__ge__ = functools.partialmethod(_cmp, operator.ge)
|
|
|
|
def __add__(self, rhs):
|
|
"""
|
|
Add a duration to an Epoch.
|
|
|
|
= INPUT VARIABLES
|
|
- rhs The Epoch to subtract.
|
|
|
|
= RETURN VALUE
|
|
- Returns the difference of ourselves and the input Epoch.
|
|
"""
|
|
t = self
|
|
if self._frame != rhs.frame():
|
|
t = self.convert(rhs._frame)
|
|
|
|
sec = t._seconds + rhs.seconds()
|
|
|
|
return Epoch(t._frame, sec, t._jd)
|
|
|
|
def __sub__(self, rhs):
|
|
"""
|
|
Subtract two Epoch's or a Duration from an Epoch.
|
|
|
|
Valid:
|
|
Duration = Epoch - Epoch
|
|
Epoch = Epoch - Duration
|
|
|
|
= INPUT VARIABLES
|
|
- rhs The Epoch to subtract.
|
|
|
|
= RETURN VALUE
|
|
- Returns either the duration between to Epoch's or the a new
|
|
Epoch that is the result of subtracting a duration from an epoch.
|
|
"""
|
|
# Delay-load due to circular dependencies.
|
|
import matplotlib.testing.jpl_units as U
|
|
|
|
# Handle Epoch - Duration
|
|
if isinstance(rhs, U.Duration):
|
|
return self + -rhs
|
|
|
|
t = self
|
|
if self._frame != rhs._frame:
|
|
t = self.convert(rhs._frame)
|
|
|
|
days = t._jd - rhs._jd
|
|
sec = t._seconds - rhs._seconds
|
|
|
|
return U.Duration(rhs._frame, days*86400 + sec)
|
|
|
|
def __str__(self):
|
|
"""Print the Epoch."""
|
|
return f"{self.julianDate(self._frame):22.15e} {self._frame}"
|
|
|
|
def __repr__(self):
|
|
"""Print the Epoch."""
|
|
return str(self)
|
|
|
|
@staticmethod
|
|
def range(start, stop, step):
|
|
"""
|
|
Generate a range of Epoch objects.
|
|
|
|
Similar to the Python range() method. Returns the range [
|
|
start, stop) at the requested step. Each element will be a
|
|
Epoch object.
|
|
|
|
= INPUT VARIABLES
|
|
- start The starting value of the range.
|
|
- stop The stop value of the range.
|
|
- step Step to use.
|
|
|
|
= RETURN VALUE
|
|
- Returns a list containing the requested Epoch values.
|
|
"""
|
|
elems = []
|
|
|
|
i = 0
|
|
while True:
|
|
d = start + i * step
|
|
if d >= stop:
|
|
break
|
|
|
|
elems.append(d)
|
|
i += 1
|
|
|
|
return elems
|