#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Time conversion, manipulation and implementation of Ticktock class
Notes
=====
The handling of time, in particular the conversions between representations,
can be more complicated than it seems on the surface. This can result in
some surprising behavior, particularly when requiring second-level accuracy and
converting between time systems outside of the period 1972 to present.
It is strongly recommended to use TAI if transferring times between SpacePy
and other libraries. TAI has a consistent, unambiguous definition and no
discontinuities.
Some time systems (e.g. the UTC representation via datetime) cannot represent
times during a leapsecond. SpacePy represents all these times as the latest
representable time in the day, e.g.::
>>> spacepy.time.Ticktock('2008-12-31T23:59:60').UTC[0]
datetime.datetime(2008, 12, 31, 23, 59, 59, 999999)
Conversions between continuous time representations (e.g. TAI), leap second
aware representations (e.g. ISO timestrings), and those that ignore leap
seconds (e.g. UTC datetime, Unix time) are well-defined between the
introduction of the leap second system to UTC in 1972 and the present.
For systems that cannot represent leap seconds, the leap second moment is
considered not to exist. For example, from 23:59:59 on 2008-12-31 to 00:00:00
on 2009-01-01 is two seconds, but only represents a one-second increment in
Unix time. Details are also discussed in the individual time representations.
UTC times more than six months in the future are not well-defined, since
the schedule of leap second insertion is not known in advance. SpacePy
performs conversions assuming there are no leapseconds after those which have
been announced by IERS.
Between 1960 and 1972, UTC was defined by means of fractional leap
seconds and a varying-length second. From 1958 (when UTC was set equal
to TAI) and 1972, SpacePy treats UTC time similar to after 1972, with
a consistent second the same length of the SI second, and applying a
full leap second before the beginning of January and July if UTC - UT1
exceeded 0.4s. The difference with other methods of calculating UTC is
less than half a second.
.. versionchanged:: 0.2.3
The application of post-1972 rules to 1958-1927 is new in
0.2.3. Before, SpacePy applied leap seconds wherever there was an
entry in the USNO record of TAI-UTC, rounding fractional total leap
second counts to the integer (0.5 rounds up). The UTC second was still
treated as the same length as the SI second (i.e., rate changed were
not applied.) This resulted in the application of six leap seconds at
the beginning of 1972. The discrepancy with other means of calculating
TAI-UTC was as much as five seconds by the end of this period.
.. versionchanged:: 0.2.2
Before 0.2.2, SpacePy truncated fractional leapseconds rather than rounding.
Before 1958, UTC is not defined. SpacePy assumes days of constant length
86400 seconds, equal to the SI second. This is almost guaranteed to be wrong;
for times well out of the space era, it is strongly recommended to work
consistently in either a continuous time system (e.g. TAI) or a day-based
system (e.g. JD).
SpacePy assumes dates including and after 1582-10-15 to be in the Gregorian
calendar and dates including and before 1582-10-04 to be Julian. 10-05 through
10-14 do not exist. This change is ignored for continuously-running non leap
second aware timebases: CDF and RDT.
See the :class:`Ticktock` documentation and its various ``get`` functions for
more details on the exact definitions of time systems used by SpacePy.
Examples:
=========
>>> import spacepy.time as spt
>>> import datetime as dt
Day of year calculations
>>> dts = spt.doy2date([2002]*4, range(186,190), dtobj=True)
>>> dts
[datetime.datetime(2002, 7, 5, 0, 0),
datetime.datetime(2002, 7, 6, 0, 0),
datetime.datetime(2002, 7, 7, 0, 0),
datetime.datetime(2002, 7, 8, 0, 0)]
>>> dts = spt.Ticktock(dts,'UTC')
>>> dts.DOY
array([ 186., 187., 188., 189.])
Ticktock object creation
>>> isodates = ['2009-12-01T12:00:00', '2009-12-04T00:00:00', '2009-12-06T12:00:00']
>>> dts = spt.Ticktock(isodates, 'ISO')
OR
>>> dtdates = [dt.datetime(2009,12,1,12), dt.datetime(2009,12,4), dt.datetime(2009,12,6,12)]
>>> dts = spt.Ticktock(dtdates, 'UTC')
ISO time formatting
>>> dts = spt.tickrange('2009-12-01T12:00:00','2009-12-06T12:00:00',2.5)
OR
>>> dts = spt.tickrange(dt.datetime(2009,12,1,12),dt.datetime(2009,12,6,12), \
dt.timedelta(days=2, hours=12))
>>> dts
Ticktock( ['2009-12-01T12:00:00', '2009-12-04T00:00:00', '2009-12-06T12:00:00'] ), dtype=ISO
>>> dts.isoformat()
Current ISO output format is %Y-%m-%dT%H:%M:%S
Options are: [('seconds', '%Y-%m-%dT%H:%M:%S'), ('microseconds', '%Y-%m-%dT%H:%M:%S.%f')]
>>> dts.isoformat('microseconds')
>>> dts.ISO
['2009-12-01T12:00:00.000000',
'2009-12-04T00:00:00.000000',
'2009-12-06T12:00:00.000000']
Time manipulation
>>> new_dts = dts + tdelt
>>> new_dts.UTC
[datetime.datetime(2009, 12, 2, 18, 0),
datetime.datetime(2009, 12, 5, 6, 0),
datetime.datetime(2009, 12, 7, 18, 0)]
Other time formats
>>> dts.RDT # Gregorian ordinal time
array([ 733742.5, 733745. , 733747.5])
>>> dts.GPS # GPS time
array([ 9.43704015e+08, 9.43920015e+08, 9.44136015e+08])
>>> dts.JD # Julian day
array([ 2455167. , 2455169.5, 2455172. ])
And so on.
.. currentmodule:: spacepy.time
.. NOTE... there is an error with this reference
Authors: Steve Morley, Josef Koller, Brian Larsen, Jon Niehof
Institution: Los Alamos National Laboratory
Contact: smorley@lanl.gov,
Copyright 2010 Los Alamos National Security, LLC.
"""
import bisect
from collections.abc import Callable, MutableSequence
import datetime
import os.path
import re
import time
import warnings
try:
import astropy.time
HAVE_ASTROPY = True
except ImportError:
HAVE_ASTROPY = False
import dateutil.parser as dup
import numpy as np
import spacepy
from spacepy import help
import spacepy.datamodel
__contact__ = 'Steve Morley, smorley@lanl.gov'
# -----------------------------------------------
# Ticktock class
# -----------------------------------------------
[docs]class Ticktock(MutableSequence):
"""
Ticktock( data, dtype )
Ticktock class holding various time coordinate systems
(TAI, UTC, ISO, JD, MJD, GPS, UNX, RDT, CDF, DOY, eDOY, APT)
Possible input data types:
ISO
ISO standard format like '2002-02-25T12:20:30'
UTC
datetime object with UTC time
TAI
Elapsed seconds since 1958-1-1 (includes leap seconds)
GPS
Elapsed seconds since 1980-1-6 (includes leap seconds)
UNX
Elapsed seconds since 1970-1-1 ignoring leapseconds (all days have
86400 secs).
JD
Julian days elapsed
MJD
Modified Julian days
RDT
Rata Die days elapsed since 0001-1-1
CDF
CDF Epoch type: float milliseconds since 0000-1-1 ignoring leapseconds
APT
AstroPy :class:`~astropy.time.Time`. Requires AstroPy 1.0.
(New in version 0.2.2.)
Possible output data types: All those listed above, plus:
DOY
Integer day of year, starts with day 1
eDOY
Fractional day of year, starts at day 0
It is strongly recommended to access various time systems via the
attributes listed above, as in the examples. They will be calculated
automatically if necessary. Using the ``get`` methods will force a
recalculation.
The original input data will always be available as the ``data``
attribute.
.. versionchanged:: 0.2.2
In earlier versions of SpacePy, most values were derived from the
``datetime``-based ``UTC`` representation. This did not properly
handle leap seconds in many cases. Now most are derived from ``TAI``
(exceptions being ``DOY`` and ``eDOY``). In addition to differences
around actual leap seconds, this may result in small differences
between versions of SpacePy, with relative magnitude on the order of the
resolution of a 64-bit float (2e-16). For times in the modern era, this
is about 50 microseconds (us) for ``JD``, 15 us for ``CDF``, 1.5 us
for ``RDT``, 1 us for ``MJD``, and 360 *nanoseconds* for ``TAI``.
The relationships between parameters and how they are calculated are
listed in the ``get`` methods and illustrated below.
.. only:: latex
.. image:: ../images/ticktock_relationships.*
.. only:: html
.. image:: ../images/ticktock_relationships.svg
:target: ../_images/ticktock_relationships1.svg
Parameters
==========
data : array_like (int, datetime, float, string)
time stamp
dtype : string {`CDF`, `ISO`, `UTC`, `TAI`, 'GPS', `UNX`, `JD`, `MJD`, `RDT`, `APT`} or function
data type for data, if a function it must convert input time format to Python datetime
Returns
=======
out : Ticktock
instance with self.data, self.dtype, self.UTC etc
Notes
=====
UTC data type is implemented as Python datetime, which cannot represent
leap seconds. The time within a leap second is regarded as not happening.
The CDF data type is the older CDF_EPOCH time type, not the newer
CDF_TIME_TT2000. It similarly cannot represent leap seconds. Year
0 is considered a leap year.
Other Parameters
================
isoformat : str, optional
.. versionadded:: 0.2.2
Format string used for parsing and outputting ISO format. Input is
not forced to be in this format; it is tried first, and other
common formats tried if parsing fails. Because of this, if ISO input
is in a consistent format, specifying this can speed up the input
parsing. Can be changed on existing ``Ticktock`` with :meth:`isoformat`
method. Default ``'%Y-%m-%dT%H:%M:%S'``.
See Also
========
datetime.datetime.strptime, isoformat
Examples
========
>>> x = Ticktock([2452331.0142361112, 2452332.0142361112], 'JD')
>>> x.ISO
dmarray(['2002-02-25T12:20:30', '2002-02-26T12:20:30'], dtype='|S19')
>>> x.DOY # Day of year
dmarray([ 56., 57.])
>>> y = Ticktock(['01-01-2013', '20-03-2013'], lambda x: datetime.datetime.strptime(x, '%d-%m-%Y'))
>>> y.UTC
dmarray([2013-01-01 00:00:00, 2013-03-20 00:00:00], dtype=object)
>>> y.DOY # Day of year
dmarray([ 1., 79.])
.. autosummary::
~Ticktock.append
~Ticktock.argsort
~Ticktock.convert
~Ticktock.getAPT
~Ticktock.getCDF
~Ticktock.getDOY
~Ticktock.getGPS
~Ticktock.getISO
~Ticktock.getJD
~Ticktock.getMJD
~Ticktock.getRDT
~Ticktock.getTAI
~Ticktock.getUNX
~Ticktock.getUTC
~Ticktock.geteDOY
~Ticktock.getleapsecs
~Ticktock.isoformat
~Ticktock.now
~Ticktock.sort
~Ticktock.today
~Ticktock.update_items
.. automethod:: append
.. automethod:: argsort
.. automethod:: convert
.. automethod:: getAPT
.. automethod:: getCDF
.. automethod:: getDOY
.. automethod:: getGPS
.. automethod:: getISO
.. automethod:: getJD
.. automethod:: getMJD
.. automethod:: getRDT
.. automethod:: getTAI
.. automethod:: getUNX
.. automethod:: getUTC
.. automethod:: geteDOY
.. automethod:: getleapsecs
.. automethod:: isoformat
.. automethod:: now
.. automethod:: sort
.. automethod:: today
.. automethod:: update_items
"""
_keylist = ['UTC', 'TAI', 'ISO', 'JD', 'MJD', 'UNX', 'RDT', 'CDF', 'GPS', 'DOY', 'eDOY', 'leaps']
if HAVE_ASTROPY:
_keylist.append('APT')
_keylist_upper = [key.upper() for key in _keylist]
_isoformatstr = {'seconds': '%Y-%m-%dT%H:%M:%S', 'microseconds': '%Y-%m-%dT%H:%M:%S.%f'}
def __init__(self, data, dtype=None, isoformat=None):
self._isofmt = isoformat or self._isoformatstr['seconds']
if isinstance(data, Ticktock):
dtype = data.data.attrs['dtype']
self.data = data.data
else:
try:
spacepy.datamodel.dmarray(data)[0]
except IndexError:
self.data = spacepy.datamodel.dmarray([data])
else:
self.data = spacepy.datamodel.dmarray(data)
if not isinstance(dtype, Callable):
if isinstance(self.data[0], (str, bytes)):
dtype = 'ISO'
elif isinstance(self.data[0], datetime.datetime):
dtype = 'UTC'
elif HAVE_ASTROPY and isinstance(self.data[0],
astropy.time.Time):
dtype = 'APT'
# Recover original input (not dmarray), add axis if scalar
self.data = astropy.time.Time([data]) if data.shape == ()\
else data
elif self.data[0] > 1e13:
dtype = 'CDF'
elif dtype is None:
raise ValueError('Unable to guess dtype from data; '
'please specify dtype.')
if dtype.upper() not in Ticktock._keylist_upper:
raise ValueError("data type " + dtype + " not provided, only " + str(Ticktock._keylist))
else:
# process input data using callable dtype to convert to datetime/UTC
dtype_func = np.vectorize(dtype)
self.data = dtype_func(self.data)
self.UTC = no_tzinfo(self.data)
# AstroPy time objects don't have attrs, but will accept one.
if not hasattr(self.data, 'attrs'):
self.data.attrs = {}
try:
self.data.attrs['dtype'] = dtype.upper()
except AttributeError:
self.data.attrs['dtype'] = str(dtype_func)
else:
# ISO is populated by update_items
self.update_items('data')
if dtype.upper() == 'TAI':
self.TAI = self.data
elif dtype.upper() == 'JD':
self.JD = self.data
elif dtype.upper() == 'MJD':
self.MJD = self.data
elif dtype.upper() == 'UNX':
self.UNX = self.data
elif dtype.upper() == 'RDT':
self.RDT = self.data
elif dtype.upper() == 'CDF':
self.CDF = self.data
elif dtype.upper() == 'UTC':
self.UTC = no_tzinfo(self.data)
elif dtype.upper() == 'APT':
self.APT = self.data
## Brian and Steve were looking at this to see about making plot work directly on the object
## is also making iterate as an array of datetimes
# def __iter__(self):
# i = 0
# try:
# while True:
# v = self[i].UTC[0]
# yield v
# i += 1
# except IndexError:
# return
# -----------------------------------------------
def __str__(self):
"""
a.__str__() or a
Will be called when printing Ticktock instance a
Returns
=======
out : string
string representaion of the class
Examples
========
>>> a = Ticktock('2002-02-02T12:00:03', 'ISO')
>>> a
Ticktock( ['2002-02-02T12:00:00'], dtype=ISO)
"""
return 'Ticktock( ' + str(self.data) + ', dtype=' + str(self.data.attrs['dtype'] + ')')
__repr__ = __str__
# -----------------------------------------------
def __getstate__(self):
"""
Is called when pickling
See Also http://docs.python.org/library/pickle.html
"""
odict = self.__dict__.copy() # copy the dict since we change it
return odict
def __setstate__(self, dict):
"""
Is called when unpickling
See Also http://docs.python.org/library/pickle.html
"""
self.__dict__.update(dict)
return
# -----------------------------------------------
def __getitem__(self, idx):
"""
a.__getitem__(idx) or a[idx]
Will be called when requesting items in this instance
Parameters
==========
idx : int
the item index to get
Returns
=======
out : Ticktock
Ticktock instance with requested values
Examples
========
>>> a = Ticktock('2002-02-02T12:00:03', 'ISO')
>>> a[0]
'2002-02-02T12:00:00'
See Also
========
a.__setitem__
"""
return Ticktock(self.UTC[idx])
# -----------------------------------------------
def __setitem__(self, idx, vals):
"""
a.__setitem__(idx, vals) or a[idx] = vals
Will be called setting items in this instance
Parameters
==========
idx : int
integer numbers as index
vals: {float, string, datetime}
new values
Examples
========
>>> a = Ticktock('2002-02-02T12:00:03', 'ISO')
>>> a[0] = '2003-03-03T00:00:00'
See Also
========
a.__getitem__
"""
tmp = Ticktock(vals)
if len(tmp) > 1:
self.data[idx] = tmp.__getattribute__(self.data.attrs['dtype'])[:]
else:
self.data[idx] = tmp.__getattribute__(self.data.attrs['dtype'])[0]
self.update_items('data')
# -----------------------------------------------
def __delitem__(self, idx):
"""
a.__delitem(index)
will be called when deleting items in the sequence
"""
self.data = np.delete(self.data, idx)
self.update_items('data')
# -----------------------------------------------
def __len__(self):
"""
a.__len__() or len(a)
Will be called when requesting the length, i.e. number of items
Returns
=======
out : int
length
Examples
========
>>> a = Ticktock('2002-02-02T12:00:03', 'ISO')
>>> a.len
1
"""
return len(self.data)
# -----------------------------------------------
def __gt__(self, other):
if isinstance(other, datetime.datetime):
other = Ticktock(other, 'UTC')
return self.UNX > other.UNX
def __lt__(self, other):
if isinstance(other, datetime.datetime):
other = Ticktock(other, 'UTC')
return self.UNX < other.UNX
def __ge__(self, other):
if isinstance(other, datetime.datetime):
other = Ticktock(other, 'UTC')
return self.UNX >= other.UNX
def __le__(self, other):
if isinstance(other, datetime.datetime):
other = Ticktock(other, 'UTC')
return self.UNX <= other.UNX
def __eq__(self, other):
if isinstance(other, datetime.datetime):
other = Ticktock(other, 'UTC')
return self.UNX == other.UNX
def __ne__(self, other):
if isinstance(other, datetime.datetime):
other = Ticktock(other, 'UTC')
return self.UNX != other.UNX
# -----------------------------------------------
def __sub__(self, other):
"""
a.__sub__(other)
Will be called if a timedelta object is subtracted from this instance and
returns a new Ticktock instance. If a Ticktock is subtracted from another
Ticktock then a list of timedeltas is returned.
Parameters
==========
other : Ticktock or datetime.timedelta
instance for comparison
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> dt = datetime.timedelta(3)
>>> a - dt
Ticktock( ['2002-02-05T12:00:00'] ), dtype=ISO
See Also
========
__add__
"""
if isinstance(other, datetime.timedelta):
newobj = Ticktock(self.UTC - other, 'UTC')
elif isinstance(other, Ticktock):
if not (len(other) == len(self.data)) and not (len(other) == 1):
raise ValueError('Ticktock lengths are mismatched, subtraction is not possible')
same = True
if len(other) == 1:
same = False
if same:
return [datetime.timedelta(seconds=t - other.TAI[i])
for i, t in enumerate(self.TAI)]
else:
return [datetime.timedelta(seconds=t - other.TAI[0])
for t in self.TAI]
elif hasattr(other, '__iter__'):
if not isinstance(other[0], datetime.timedelta):
raise TypeError("Data supplied for addition is of the wrong type")
if not (len(other) == len(self.data)) or (len(other) == 1):
raise TypeError("Data supplied for addition is of the wrong shape")
same = True
if len(other) == 1: same = False
if same:
newUTC = [utc - o for utc, o in zip(self.UTC, other)]
else:
newUTC = [utc - other for utc in self.UTC]
newobj = Ticktock(newUTC, 'UTC')
else:
raise TypeError("unsupported operand type(s) for -: {0} and {1}".format(type(other), type(self)))
return newobj
# -----------------------------------------------
def __add__(self, other):
"""
a.__add__(other)
Will be called if an iterable of datetime.timedeltas is added to this instance and
returns a new Ticktock instance
Parameters
==========
other : datetime.timedelta
instance for comparison
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> import datetime as dt
>>> delt = dt.timedelta(minutes=1)
>>> a + delt
Ticktock( ['2002-02-02T12:01:00'] , dtype=ISO)
See Also
========
__sub__
"""
if isinstance(other, datetime.timedelta):
newobj = Ticktock(self.UTC + other, 'UTC')
elif hasattr(other, '__iter__'):
if not isinstance(other[0], datetime.timedelta):
raise TypeError("Data supplied for addition is of the wrong type")
if not (len(other) == len(self.data)) or (len(other) == 1):
raise TypeError("Data supplied for addition is of the wrong shape")
same = True
if len(other) == 1: same = False
if same:
newUTC = [utc + o for utc, o in zip(self.UTC, other)]
else:
newUTC = [utc + other for utc in self.UTC]
newobj = Ticktock(newUTC, 'UTC')
else:
raise TypeError("unsupported operand type(s) for +: {0} and {1}".format(type(other), type(self)))
return newobj
def __radd__(self, other):
"""
a.__radd__(other)
reverse add -- Will be called if this object is added to a datetime.timedelta and
returns a new Ticktock instance
Parameters
==========
other : datetime.timedelta
instance for comparison
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> import datetime as dt
>>> delt = dt.timedelta(minutes=1)
>>> a + delt
Ticktock( ['2002-02-02T12:01:00'] , dtype=ISO)
See Also
========
__sub__
"""
return self.__add__(other)
# -----------------------------------------------
def __getattr__(self, name):
"""
a.__getattr__(name)
Will be called if attribute "name" is not found in Ticktock class instance.
It will add TAI, RDT, etc
Parameters
==========
name : string
a string from the list of time systems
'UTC', 'TAI', 'ISO', 'JD', 'MJD', 'UNX', 'RDT', 'CDF', 'DOY', 'eDOY', 'leaps'
Returns
=======
out: list, array
requested values as either list/numpy array
"""
if name not in Ticktock._keylist:
raise AttributeError("data type {} not provided, only {}".format(
str(name), str(Ticktock._keylist)))
if name.upper() == 'TAI': self.TAI = self.getTAI()
if name.upper() == 'UTC': self.UTC = self.getUTC()
if name.upper() == 'ISO': self.ISO = self.getISO()
if name.upper() == 'JD': self.JD = self.getJD()
if name.upper() == 'MJD': self.MJD = self.getMJD()
if name.upper() == 'UNX': self.UNX = self.getUNX()
if name.upper() == 'RDT': self.RDT = self.getRDT()
if name.upper() == 'CDF': self.CDF = self.getCDF()
if name.upper() == 'DOY': self.DOY = self.getDOY()
if name.upper() == 'EDOY': self.eDOY = self.geteDOY()
if name.upper() == 'GPS': self.GPS = self.getGPS()
if name.upper() == 'APT': self.APT = self.getAPT()
# if name == 'isoformat': self.__isofmt = self.isoformat()
if name == 'leaps': self.leaps = self.getleapsecs()
return getattr(self, name)
# -----------------------------------------------
def insert(self, idx, val, dtype=None):
"""
insert values into the TickTock object
.. note:: If more than one value to insert a slice must be specified
as the index. See numpy.insert
Parameters
==========
idx : int, slice or sequence of ints
Object that defines the index or indices before which `val` is inserted.
val : array_like
values to insert
dtype : str (optional)
must be specified if not CDF, ISO, or UTC
"""
fmt = self.data.attrs['dtype']
if not dtype:
dum = Ticktock(val)
else:
dum = Ticktock(val, dtype=dtype)
ival = getattr(dum, fmt)
self.data = np.insert(self.data, idx, ival)
self.update_items('data')
# -----------------------------------------------
def remove(self, idx):
"""
a.remove(idx)
This will remove the Ticktock value at index idx
"""
del self[idx]
# -----------------------------------------------
[docs] def sort(self, kind='quicksort'):
"""
a.sort()
This will sort the Ticktock values in place based on the values
in `data`. If you need a stable sort use kind='mergesort'
Other Parameters
================
kind : str
Sort algorithm to use, default 'quicksort'.
See Also
========
argsort, numpy.argsort
"""
idx = self.argsort(kind=kind)
self.data = self.data[idx]
self.update_items('data')
# -----------------------------------------------
[docs] def argsort(self, kind='quicksort'):
"""
idx = a.argsort()
This will return the indices that would sort the Ticktock values
Returns
=======
out : list
indices that would sort the Ticktock values
Other Parameters
================
kind : str, optional
Sort algorithm to use, default 'quicksort'.
.. versionchanged:: 0.2.2
Default is now 'quicksort' to match numpy default;
previously was 'mergesort'.
See Also
========
argsort, numpy.argsort
"""
return np.argsort(self.TAI, kind=kind)
# -----------------------------------------------
# -----------------------------------------------
[docs] def update_items(self, attrib):
"""
a.update_items(attrib)
After changing the self.data attribute by either __setitem__ or __add__ etc
this function will update all other attributes. This function is
called automatically in __add__, __init__, and __setitem__.
Parameters
==========
attrib : str
attribute that was updated; update others from this
See Also
========
spacepy.Ticktock.__setitem__
spacepy.Ticktock.__add__
spacepy.Ticktock.__sub__
"""
keylist = dir(self)
keylist.remove('data')
if attrib != 'data':
keylist.remove(attrib)
attrib = attrib.upper()
if attrib != self.data.attrs['dtype']:
# Repopulating based on a different dtype, so make a temp
# Ticktock to do the conversion.
cls = type(self)
dt = self.data.attrs['dtype']
self.data = getattr(
cls(getattr(self, attrib), dtype=attrib), dt)
if self.data.attrs['dtype'] in (
'TAI', 'GPS', 'JD', 'MJD', 'RDT', 'CDF', 'UNX', 'ISO', 'APT'):
if self.data.attrs['dtype'] == 'ISO':
if 'UTC' in keylist:
del self.UTC # Force recalc of UTC in TAI calc
if 'ISO' in keylist:
del self.ISO # Also will recalc the ISO
del keylist[keylist.index('ISO')] # So no need to calc again
self.TAI = self.getTAI()
if 'UTC' in keylist and self.data.attrs['dtype'] != 'ISO':
self.UTC = self.getUTC()
else:
self.UTC = self.getUTC()
if 'TAI' in keylist:
self.TAI = self.getTAI()
for key in keylist:
if key.upper() == 'ISO': self.ISO = self.getISO()
if key.upper() == 'JD': self.JD = self.getJD()
if key.upper() == 'MJD': self.MJD = self.getMJD()
if key.upper() == 'UNX': self.UNX = self.getUNX()
if key.upper() == 'RDT': self.RDT = self.getRDT()
if key.upper() == 'CDF': self.CDF = self.getCDF()
if key.upper() == 'DOY': self.DOY = self.getDOY()
if key.upper() == 'EDOY': self.eDOY = self.geteDOY()
if key.upper() == 'GPS': self.GPS = self.getGPS()
if key.upper() == 'APT': self.APT = self.getAPT()
if key == 'leaps': self.leaps = self.getleapsecs()
return
# -----------------------------------------------
[docs] def convert(self, dtype):
"""
a.convert(dtype)
convert a Ticktock instance into a new time coordinate system provided in dtype
Parameters
==========
dtype : string
data type for new system, possible values are {`CDF`, `ISO`, `UTC`, `TAI`, `UNX`, `JD`, `MJD`, `RDT`}
Returns
=======
out : Ticktock
Ticktock instance with new time coordinates
Examples
========
>>> a = Ticktock(['2002-02-02T12:00:00', '2002-02-02T12:00:00'], 'ISO')
>>> s = a.convert('TAI')
>>> type(s)
<class 'time.Ticktock'>
>>> s
Ticktock( [1391342432 1391342432] ), dtype=TAI
See Also
========
CDF
ISO
UTC
"""
newdat = getattr(self, dtype)
return Ticktock(newdat, dtype)
# -----------------------------------------------
[docs] def append(self, other):
"""
a.append(other)
Will be called when another Ticktock instance has to be appended to the current one
Parameters
==========
other : Ticktock
other (Ticktock instance)
"""
otherdata = getattr(other, self.data.attrs['dtype'])
return Ticktock(np.append(self.data, otherdata), dtype=self.data.attrs['dtype'])
# -----------------------------------------------
[docs] def getCDF(self):
"""
a.getCDF() or a.CDF
Return CDF Epoch time which is milliseconds since 0000-1-1 at
00:00:00.000. "Year zero" is a convention chosen by NSSDC to measure
epoch values. This date is more commonly referred to as 1 BC and is
considered a leap year.
The CDF date/time calculations do not take into account the change
to the Gregorian calendar or leap seconds, and cannot be directly
converted into Julian date/times.
Returns ``data`` if it was provided in CDF; otherwise always
recalculates from the current value of ``TAI``, which will be
created if necessary.
Updates the ``CDF`` attribute.
Returns
=======
out : numpy array
milliseconds since 0000-01-01T00:00:00 assuming no discontinuities.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.CDF
array([ 6.31798704e+13])
See Also
========
getUTC
getUNX
getRDT
getJD
getMJD
getISO
getTAI
getDOY
geteDOY
getAPT
"""
if self.data.attrs['dtype'] == 'CDF':
# This should be the case from the constructor
self.CDF = self.data
return self.CDF
CDFofTAI0 = 61788528000000.
naive_tai = _tai_real_to_naive(self.TAI)
cdf = naive_tai * 1e3 + CDFofTAI0
self.CDF = spacepy.datamodel.dmarray(cdf, attrs={'dtype': 'CDF'})
return self.CDF
# -----------------------------------------------
[docs] def getDOY(self):
"""
a.DOY or a.getDOY()
extract DOY (days since January 1st of given year)
Always recalculates from the current value of ``UTC``, which will
be created if necessary.
Updates the ``DOY`` attribute.
Returns
=======
out : numpy array
day of the year
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.DOY
array([ 33])
See Also
========
getUTC
getUNX
getRDT
getJD
getMJD
getISO
getTAI
getDOY
geteDOY
getAPT
"""
DOY = [utc.toordinal() - datetime.date(utc.year, 1, 1).toordinal() + 1 for utc in self.UTC]
self.DOY = spacepy.datamodel.dmarray(DOY, attrs={'dtype': 'DOY'}).astype(int)
return self.DOY
# -----------------------------------------------
[docs] def geteDOY(self):
"""
a.eDOY or a.geteDOY()
extract eDOY (elapsed days since midnight January 1st of given year)
Always recalculates from the current value of ``UTC``, which will
be created if necessary.
Updates the ``eDOY`` attribute.
Returns
=======
out : numpy array
days elapsed since midnight bbedJan. 1st
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.eDOY
array([ 32.5])
See Also
========
getUTC
getUNX
getRDT
getJD
getMJD
getISO
getTAI
getDOY
geteDOY
getAPT
"""
eDOY = [utc.toordinal() - datetime.date(utc.year, 1, 1).toordinal() for utc in self.UTC]
eDOY = [edoy + utc.hour / 24. + utc.minute / 1440. + utc.second / 86400. + utc.microsecond / 86400000000.
for edoy, utc in zip(eDOY, self.UTC)]
self.eDOY = spacepy.datamodel.dmarray(eDOY, attrs={'dtype': 'eDOY'})
return self.eDOY
# -----------------------------------------------
[docs] def getJD(self):
"""
a.JD or a.getJD()
convert dtype data into Julian Date (JD)
Returns ``data`` if it was provided in JD; otherwise always
recalculates from the current value of ``TAI``, which will be
created if necessary.
Updates the ``JD`` attribute.
Returns
=======
out : numpy array
elapsed days since 4713 BCE 01-01T12:00
Notes
=====
This is based on the UTC day, defined as JD(UTC),
per the recommendation
of `IAU General Assembly XXIII resolution B1
<https://www.iers.org/IERS/EN/Science/Recommendations/
resolutionB1.html>`_.
Julian days with leapseconds are 86401 seconds long and each second
is a smaller fraction of the day. Note this "stretching" is across
the *Julian* Day, noon to noon.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.JD
array([ 2452308.])
See Also
========
getUTC
getUNX
getRDT
getJD
getMJD
getISO
getTAI
getDOY
geteDOY
getAPT
"""
if self.data.attrs['dtype'] == 'JD':
# This should be the case from the constructor
self.JD = self.data
return self.JD
# 1958-01-01T12:00 is JD 2436205.0
JDofTAI0 = 2436205.0 # Days-since-1958 is relative to noon
self.JD = _days1958(self.TAI, leaps='rubber') + JDofTAI0
return self.JD
# -----------------------------------------------
[docs] def getMJD(self):
"""
a.MJD or a.getMJD()
convert dtype data into MJD (modified Julian date)
Returns ``data`` if it was provided in MJD; otherwise always
recalculates from the current value of ``TAI`` which will be
created if necessary.
Updates the ``MJD`` attribute.
Returns
=======
out : numpy array
elapsed days since 1858-11-17T00:00
(Julian date of 1858-11-17T12:00 was 2 400 000)
Notes
=====
This is based on the UTC day, defined as JD(UTC) - 2 400 000.5,
per the recommendation
of `IAU General Assembly XXIII resolution B1
<https://www.iers.org/IERS/EN/Science/Recommendations/
resolutionB1.html>`_.
Julian days with leapseconds are 86401 seconds long and each second
is a smaller fraction of the day. Note this "stretching" is across
the *Julian* Day not the MJD, so it will affect the last half of
the MJD before the leap second and the first half of the following
MJD, so that MJD is always JD - 2 400 000.5 This also means that
the MJD following a leap second does not begin exactly at midnight.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.MJD
array([ 52307.5])
>>> a = Ticktock('2009-01-01T00:00:00', 'ISO')
>>> a.MJD
array([ 54832.00000579])
See Also
========
getUTC, getUNX, getRDT, getJD, getISO, getCDF, getTAI, getDOY, geteDOY,
getAPT
"""
if self.data.attrs['dtype'] == 'MJD':
# This should be the case from the constructor
self.MJD = self.data
return self.MJD
# 1958-01-01T12:00 is MJD 36204.5 (days since 1858-11-17T00:00)
self.MJD = _days1958(self.TAI, leaps='rubber') + 36204.5
return self.MJD
# -----------------------------------------------
[docs] def getUNX(self):
"""
a.UNX or a.getUNX()
convert dtype data into Unix Time (Posix Time)
seconds since 1970-1-1 (not counting leap seconds)
Returns ``data`` if it was provided in UNX; otherwise always
recalculates from the current value of ``TAI``, which will be
created if necessary.
Updates the ``UNX`` attribute.
Returns
=======
out : numpy array
elapsed secs since 1970-1-1 (not counting leap secs)
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.UNX
array([ 1.01265120e+09])
See Also
========
getUTC, getISO, getRDT, getJD, getMJD, getCDF, getTAI, getDOY, geteDOY,
getAPT
"""
if self.data.attrs['dtype'] == 'UNX':
# This should be the case from the constructor
self.UNX = self.data
return self.UNX
naive_tai = _tai_real_to_naive(self.TAI)
UNXofTAI0 = -378691200.
unx = naive_tai + UNXofTAI0
self.UNX = spacepy.datamodel.dmarray(unx, attrs={'dtype': 'UNX'})
return self.UNX
# -----------------------------------------------
[docs] def getRDT(self):
"""
a.RDT or a.RDT()
convert dtype data into Rata Die (lat.) Time, or elapsed days
counting 0001-01-01 as day 1. This is a naive conversion: it
ignores the existence of leapseconds for fractional days and
ignores the conversion from Julian to Gregorian calendar, i.e.
it assumes Gregorian calendar infinitely into the past.
Returns ``data`` if it was provided in RDT; otherwise always
recalculates from the current value of ``TAI``, which will be
created if necessary.
Updates the ``RDT`` attribute.
Returns
=======
out : numpy array
elapsed days counting 1/1/1 as day 1.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.RDT
array([ 730883.5])
See Also
========
getUTC, getUNX, getISO, getJD, getMJD, getCDF, getTAI, getDOY, geteDOY,
getAPT
"""
if self.data.attrs['dtype'] == 'RDT':
# This should be the case from the constructor
self.RDT = self.data
return self.RDT
# RDT date at 1958-1-1T00
RDTTAI0 = 714780.0
RDT = _days1958(self.TAI, leaps='drop', midnight=True) + RDTTAI0
# RDT can represent 1582-10-5 through 1582-10-14, which do not exist.
# So everything before 1582-10-15 (RDT day 577736) is ten days earlier.
RDT[RDT < 577736.0] -= 10
self.RDT = spacepy.datamodel.dmarray(RDT, attrs={'dtype': 'RDT'})
return self.RDT
# -----------------------------------------------
[docs] def getUTC(self):
"""
a.UTC or a.getUTC()
convert dtype data into UTC object a la datetime()
Return value comes from (in priority order):
1. If ``data`` was provided in UTC, returns ``data``.
2. Else recalculates directly from ``data`` if it was
provided in ISO.
3. Else calculates from current value of ``TAI``, which
will be created if necessary. (``data`` is TAI, GPS,
JD, MJD, RDT, CDF, UNX)).
Updates the ``UTC`` attribute.
Returns
=======
out : list of datetime objects
datetime object in UTC time
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.UTC
[datetime.datetime(2002, 2, 2, 12, 0)]
See Also
========
getISO, getUNX, getRDT, getJD, getMJD, getCDF, getTAI, getDOY, geteDOY,
getAPT
"""
nTAI = len(self.data)
# if already UTC, we are done, no conversion
if self.data.attrs['dtype'].upper() == 'UTC':
UTC = self.data
elif self.data.attrs['dtype'].upper() == 'ISO':
self.ISO = self.data
_, UTC, _ = dtstr2iso(self.data, fmt=self._isofmt)
elif self.data.attrs['dtype'].upper() in (
'TAI', 'GPS', 'JD', 'MJD', 'RDT', 'CDF', 'UNX', 'APT'):
TAI0 = datetime.datetime(1958, 1, 1, 0, 0, 0, 0)
UTC = [datetime.timedelta(
# Before 1582-10-15, UTC 10 days earlier than naive conversion
# since those dates are Julian not Gregorian.
seconds=float(tait - (864000 if tait < -11840601600.0 else 0)))
+ TAI0 for tait in self.TAI]
for i in np.arange(nTAI):
# This is the index of number of seconds to subtract from
# "naive" UTC, not just TAI - UTC.
# TAI of leap second does not have a new TAI - UTC, this
# is because UTC seconds = 60, but need to subtract off
# one more to make the UTC seconds = 59 in that case, thus
# "flip" to next leap second count 1s earlier.
idx = np.searchsorted(TAIleaps, self.TAI[i], side='right') - 1
UTC[i] = UTC[i] - datetime.timedelta(seconds=secs[idx]
if idx > 0 else 0)
if int(self.TAI[i]) == TAIleaps[idx]:
# TAI is in leap second
UTC[i] = UTC[i].replace(
second=59, microsecond=999999)
else:
warnstr1 = 'Input data type {0} does not support calculation of UTC times'.format(self.data.attrs['dtype'])
warnstr2 = 'Valid input dtypes are: {0}'.format(
', '.join([kk for kk in Ticktock._keylist if kk not in ['DOY', 'eDOY', 'leaps']]))
raise TypeError('{0}\n{1}'.format(warnstr1, warnstr2))
self.UTC = spacepy.datamodel.dmarray(UTC, attrs={'dtype': 'UTC'})
return self.UTC
# -----------------------------------------------
[docs] def getGPS(self):
"""
a.GPS or a.getGPS()
Return seconds since the GPS epoch (1980-1-6T00:00 UT)
Always recalculates from the current value of ``TAI``, which
will be created if necessary.
Updates the ``GPS`` attribute.
Returns
=======
out : numpy array
elapsed secs since 1980-1-6. Leap seconds are counted;
i.e. there are no discontinuities.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.GPS
dmarray([6.96686413e+08])
See Also
========
getUTC, getUNX, getRDT, getJD, getMJD, getCDF, getISO, getDOY, geteDOY,
getAPT
"""
if self.data.attrs['dtype'] == 'GPS':
# This should be the case from the constructor
self.GPS = self.data
return self.GPS
GPS0 = 694656019
self.GPS = spacepy.datamodel.dmarray(
self.TAI - GPS0, attrs={'dtype': 'GPS'})
return self.GPS
# -----------------------------------------------
[docs] def getAPT(self):
"""
a.APT or a.getAPT()
Return AstroPy time object.
Always recalculates from the current value of ``TAI``, which
will be created if necessary.
Updates the ``APT`` attribute.
Returns
=======
out : astropy.time.Time
AstroPy Time object
Notes
=====
.. versionadded:: 0.2.2
Requires AstroPy 1.0. The returned value will be on the ``tai``
scale in ``gps`` format (unless the :class:`Ticktock` was created
from a :class:`~astropy.time.Time` object, in which case it will
be the original input.) See the :mod:`astropy.time` docs for
conversion to other scales and formats.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.APT
<Time object: scale='tai' format='gps' value=696686413.0>
See Also
========
getUTC, getUNX, getRDT, getJD, getMJD, getCDF, getISO, getDOY, geteDOY,
getGPS
"""
if self.data.attrs['dtype'] == 'APT':
# This should be the case from the constructor
self.APT = self.data
return self.APT
if not HAVE_ASTROPY:
raise RuntimeError('Import of astropy.time failed.')
GPS0 = 694656019
self.APT = astropy.time.Time(
self.TAI - GPS0, scale='tai', format='gps')
self.APT.attrs = {'dtype': 'APT'}
return self.APT
# -----------------------------------------------
[docs] def getTAI(self):
"""
a.TAI or a.getTAI()
return TAI (International Atomic Time), elapsed secs since 1958-1-1
(leap seconds are counted.) Ticktock's handling of TAI and UTC
conversions treats the UTC second as always equal in length to the SI
second (and thus TAI), ignoring frequency changes and fractional
leap seconds from 1958 through 1972, i.e. the UTC to TAI offset
is always treated as an integer, truncated (not rounded) from the
value at the most recent leap second (or fraction thereof).
Return value comes from (in priority order):
1. If ``data`` was provided in TAI, returns ``data``.
2. Else recalculates directly from ``data`` if it was
provided in APT, CDF, GPS, ISO, JD, MJD, RDT, or UNX.
3. Else calculates from current value of ``UTC``, which
will be created if necessary.
Updates the ``TAI`` attribute; will also create the ``UTC``
and ``ISO`` attributes from ``data`` if input is in ``ISO``
(but will not overwrite an existing ``ISO`` or ``UTC``). This is
for efficiency, as computation from ISO requires calculating UTC
and makes creating a formatted ISO string easy.
Returns
=======
out : numpy array
TAI as seconds since 1958-1-1.
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.TAI
array([1391342432])
See Also
========
getUTC, getUNX, getRDT, getJD, getMJD, getCDF, getISO, getDOY, geteDOY,
getAPT
"""
if self.data.attrs['dtype'] == 'TAI':
# This should be the case from the constructor
self.TAI = self.data
return self.TAI
if self.data.attrs['dtype'] == 'GPS':
GPS0 = 694656019
self.TAI = spacepy.datamodel.dmarray(
self.data + GPS0, attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'MJD':
MJDofTAI0 = 36204.5 # Days-since-1958 is relative to noon
self.TAI = spacepy.datamodel.dmarray(
_days1958totai(
np.require(self.data, dtype=np.float64)
- MJDofTAI0, leaps='rubber', midnight=False),
attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'JD':
JDofTAI0 = 2436205.0 # Days-since-1958 is relative to noon
self.TAI = spacepy.datamodel.dmarray(
_days1958totai(
np.require(self.data, dtype=np.float64)
- JDofTAI0, leaps='rubber', midnight=False),
attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'RDT':
RDTofTAI0 = 714780. #RDT date of 1958-1-1T00
tai = _days1958totai(
np.require(self.data, dtype=np.float64)
- RDTofTAI0, leaps='drop', midnight=True)
# Anything before 1582-10-5 has TAI ten days later than the
# naive conversion, because RDT has ten days that are not in TAI.
tai[tai < -11840601600.0] += 864000
self.TAI = spacepy.datamodel.dmarray(tai, attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'CDF':
CDFofTAI0 = 61788528000000.0
# Naive TAI conversion
tai = (self.data - CDFofTAI0) / 1.e3
tai = _tai_naive_to_real(tai)
self.TAI = spacepy.datamodel.dmarray(tai, attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'UNX':
UNXofTAI0 = -378691200.
# Naive TAI
tai = self.data - UNXofTAI0
tai = _tai_naive_to_real(tai)
self.TAI = spacepy.datamodel.dmarray(tai, attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'APT':
# AstroPy time doesn't support TAI directly, have to go relative
# to GPS. But since it's a simple offset, just do the math here
# instead of via the GPS attribute.
GPS0 = 694656019
self.TAI = spacepy.datamodel.dmarray(
self.data.gps + GPS0, attrs={'dtype': 'TAI'})
return self.TAI
if self.data.attrs['dtype'] == 'ISO':
isoout, UTC, offset = dtstr2iso(self.data, self._isofmt)
if 'UTC' not in dir(self):
self.UTC = spacepy.datamodel.dmarray(
UTC, attrs={'dtype': 'UTC'})
if 'ISO' not in dir(self):
self.ISO = spacepy.datamodel.dmarray(
isoout, attrs={'dtype': 'ISO'})
else:
UTC = self.UTC
offset = None
TAI0 = datetime.datetime(1958, 1, 1, 0, 0, 0, 0)
leapsec = self.getleapsecs()
TAItup = [utc - TAI0 + datetime.timedelta(seconds=int(ls)) for utc, ls in zip(UTC, leapsec)]
if offset is not None:
TAI = [tai.days * 86400 + tai.seconds
+ (tai.microseconds + offset[i])/ 1.e6
for i, tai in enumerate(TAItup)]
else:
TAI = [tai.days * 86400 + tai.seconds + tai.microseconds / 1.e6
for tai in TAItup]
TAI = spacepy.datamodel.dmarray(TAI, attrs={'dtype': 'TAI'})
# 1582-10-5 through 1582-10-14 do not exist, so anything
# before 1582-10-15 is 10 TAI days later than the naive conversion.
TAI[TAI < -11840601600.0] += (86400 * 10)
self.TAI = TAI
return self.TAI
# -----------------------------------------------
[docs] def getISO(self):
"""
a.ISO or a.getISO()
convert dtype data into ISO string
Always recalculates from the current value of ``UTC``, which
will be created if necessary. Applies leapsecond correction
based on ``TAI``, also created as necessary.
Updates the ``ISO`` attribute.
Returns
=======
out : list of strings
date in ISO format
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.ISO
dmarray(['2002-02-02T12:00:00'])
See Also
========
getUTC, getUNX, getRDT, getJD, getMJD, getCDF, getTAI, getDOY, geteDOY,
getAPT
"""
if self.data.attrs['dtype'] == 'ISO': # Convert the string directly.
self.ISO = spacepy.datamodel.dmarray(
dtstr2iso(self.data, fmt=self._isofmt)[0],
attrs={'dtype': 'ISO'})
return self.ISO
nTAI = len(self.data)
self.TAI = self.getTAI()
try:
iso = [utc.strftime(self._isofmt) for utc in self.UTC]
except ValueError: # Python before 3.3 fails on strftime before 1900.
iso = [utc.replace(year=1900).strftime(
self._isofmt.replace('%Y', str(utc.year))) for utc in self.UTC]
self.ISO = spacepy.datamodel.dmarray(iso, attrs={'dtype': 'ISO'})
for i in range(nTAI):
if int(self.TAI[i]) in TAIleaps:
# UTC is 23:59:59.9999, get correct number of microseconds
tmpdt = self.UTC[i].replace(
microsecond=int((self.TAI[i] % 1) * 1e6))
# And fudge the second
a, b, c = tmpdt.strftime(self._isofmt).split(':')
cnew = c.replace('59', '60')
self.ISO[i] = a + ':' + b + ':' + cnew
return self.ISO
# -----------------------------------------------
[docs] def getleapsecs(self):
"""
a.leaps or a.getleapsecs()
retrieve leapseconds from lookup table, used in getTAI
Always recalculates from current value of ``TAI`` if ``data``
is dtype ``TAI``, otherwise from the current value of ``UTC``,
which will be created if necessary.
Updates the ``leaps`` attribute.
Returns
=======
out : numpy array
leap seconds
Examples
========
>>> a = Ticktock('2002-02-02T12:00:00', 'ISO')
>>> a.leaps
array([32])
See Also
========
getTAI
"""
if self.data.attrs['dtype'] == 'TAI':
# TAIleaps contains the TAI which IS the leap second.
# The leap second count increments in the NEXT second.
# (TAI - UTC changes at end of leap second.)
# So find the latest index where the TAI-after-leap-second
# is less than current TAI (i.e. we are not after leap second yet).
idx = np.searchsorted(TAIleaps + 1, self.data, side='right') - 1
return secs[idx]
tup = self.UTC
# check if array:
if isinstance(tup, datetime.datetime): # not an array of objects
tup = [tup]
nTAI = 1
aflag = False
else:
nTAI = len(tup)
aflag = True
# convert them into a time tuple and find the correct leap seconds
self.TAIleaps = TAIleaps
leaps = [secs[0]] * nTAI
leap_dates = [datetime.datetime(int(y), int(m), int(d)) for
y, m, d, s in zip(year, mon, day, secs)]
for i, itup in enumerate(tup):
ind = bisect.bisect_right(leap_dates, tup[i])
leaps[i] = secs[ind - 1] if ind > 0 else 0
## ldatetime = datetime.datetime # avoid an expensive lookup below
## for i, itup in enumerate(tup):
## for y,m,d,s in zip(year, mon, day, secs):
## if tup[i] >= ldatetime(int(y),int(m),int(d)):
## leaps[i] = s
## else:
## break
# if datetime.datetime(1971,12,31) > tup[0]:
# print "WARNING: date before 1972/1/1; leap seconds are by fractions off"
if aflag == False:
self.leaps = int(leaps[0])
return int(leaps[0]) # if you want to allow fractional leap seconds, remove 'int' here
else:
self.leaps = np.array(leaps, dtype=int)
return self.leaps
# -----------------------------------------------
[docs] @classmethod
def now(cls):
"""
Create Ticktock with the current UTC time.
Equivalent to datetime.utcnow()
.. versionchanged:: 0.2.2
This now returns a UTC time; previously it returned a Ticktock
UTC object, but in the local timezone, which made all conversions
incorrect.
Returns
=======
out : ticktock
Ticktock object with the current time, equivalent to datetime.utcnow()
See Also
========
datetime.datetime.now, datetime.datetime.utcnow
"""
try:
dt = datetime.datetime.now(datetime.UTC).replace(tzinfo=None)
except AttributeError:
dt = datetime.datetime.utcnow()
return Ticktock(dt, 'UTC')
# -----------------------------------------------
[docs] @classmethod
def today(cls):
"""
Create Ticktock with the current UTC date and time set to 00:00:00
Similar to date.today() with time included but in UTC and with the
time included (zero hours, minutes, seconds)
.. versionchanged:: 0.2.2
This now returns the UTC day; previously it returned a Ticktock
UTC object, but in the local timezone, which made all conversions
incorrect.
Returns
=======
out : ticktock
Ticktock object with the current UTC day
See Also
========
datetime.date.today
"""
warnings.warn('today() returns UTC day as of 0.2.2.',
DeprecationWarning)
try:
dt = datetime.datetime.now(datetime.UTC).replace(tzinfo=None)
except AttributeError:
dt = datetime.datetime.utcnow()
dt = dt.replace(hour=0, minute=0, second=0, microsecond=0)
return Ticktock(dt, 'UTC')
# -----------------------------------------------
# End of Ticktock class
# -----------------------------------------------
[docs]def doy2date(year, doy, dtobj=False, flAns=False):
"""
convert integer day-of-year doy into a month and day
after http://pleac.sourceforge.net/pleac_python/datesandtimes.html
Parameters
==========
year : int or array of int
year
doy : int or array of int
day of year
Returns
=======
month : int or array of int
month as integer number
day : int or array of int
as integer number
Examples
========
>>> month, day = doy2date(2002, 186)
>>> dts = doy2date([2002]*4, range(186,190), dtobj=True)
See Also
========
Ticktock.getDOY
"""
try:
n_year = len(year)
except TypeError:
n_year = -1 # Special case: this is a scalar
try:
n_doy = len(doy)
except TypeError:
n_doy = -1
if n_doy != n_year:
raise ValueError('Day of year and year must have same length')
if n_year == -1:
if doy < 1:
raise ValueError(
'Day-of-Year less than 1 detected: DOY starts from 1')
if not flAns:
dt = datetime.datetime(int(year), 1, 1) + \
datetime.timedelta(days=int(doy) - 1)
else:
dt = datetime.datetime(year, 1, 1) + \
datetime.timedelta(days=float(doy) - 1)
if dtobj:
return dt
else:
return dt.month, dt.day
if min(doy) < 1:
raise ValueError('Day-of-Year less than 1 detected: DOY starts from 1')
if flAns:
dateobj = spacepy.datamodel.dmarray([datetime.datetime(year[i], 1, 1) +
datetime.timedelta(days=float(doy[i]) - 1)
for i in range(n_year)])
else:
dateobj = spacepy.datamodel.dmarray([datetime.datetime(int(year[i]), 1, 1) +
datetime.timedelta(days=int(doy[i]) - 1)
for i in range(n_year)])
if dtobj:
return dateobj
else:
return (spacepy.datamodel.dmarray([dt.month for dt in dateobj]),
spacepy.datamodel.dmarray([dt.day for dt in dateobj]))
# -----------------------------------------------
[docs]def tickrange(start, end, deltadays, dtype=None):
"""
return a Ticktock range given the start, end, and delta
Parameters
==========
start : string or number
start time (ISO standard string and UTC/datetime do not require a dtype)
end : string or number
last possible time in series (excluded unless end=start+n*step for integer n)
deltadays : float or timedelta
step in units of days (float); or datetime timedelta object
dtype : string (optional)
data type for start, end; e.g. ISO, UTC, RTD, etc. see Ticktock for all options
Returns
=======
out : Ticktock instance
ticks
Examples
========
>>> ticks = st.tickrange('2002-02-01T00:00:00', '2002-02-10T00:00:00', deltadays = 1)
>>> ticks
Ticktock( ['2002-02-01T00:00:00', '2002-02-02T00:00:00', '2002-02-03T00:00:00',
'2002-02-04T00:00:00'] , dtype=ISO)
See Also
========
Ticktock
"""
Tstart = Ticktock(start, dtype)
Tend = Ticktock(end, dtype)
diff = Tend.UTC[0] - Tstart.UTC[0]
dmusec, dsec = diff.microseconds / 86400000000., diff.seconds / 86400.
if isinstance(deltadays, datetime.timedelta):
musec, sec = deltadays.microseconds / 86400000000., deltadays.seconds / 86400.
deltat = musec + sec + deltadays.days
nticks = int((dmusec + dsec + diff.days) / deltat + 1)
trange = [Tstart.UTC[0] + deltadays * n for n in range(nticks)]
else:
nticks = int((dmusec + dsec + diff.days) / float(deltadays) + 1)
trange = [Tstart.UTC[0] + datetime.timedelta(days=deltadays) * n for n in range(nticks)]
ticks = Ticktock(trange, 'UTC')
return ticks
[docs]def dtstr2iso(dtstr, fmt='%Y-%m-%dT%H:%M:%S'):
"""Convert a datetime string to a standard format
Attempts to maintain leap second representation while converting
time strings to the specified format (by default, ISO8601-like.)
Only handles a single positive leap second; negative leap seconds
require no special handling and policy is for UTC-UT1 not to
exceed 0.9.
Parameters
==========
dtstr : sequence of str
Date + time representation, format is fairly open.
Returns
=======
isostr : array of str
Representation of `dtstr` formatted according to `fmt`.
Always a new sequence even if contents are identical to `dtstr`.
UTC : array of datetime.datetime
The closest-possible rendering of UTC time before or equal to `dtstr`.
offset : array of int
Amount (in microseconds) to add to `UTC` to get the real time.
Other Parameters
================
fmt : str, optional
Format appropriate for :meth:`~datetime.datetime.strftime` for
rendering the output time.
"""
indtstr = dtstr
# Will be editing this, so force it to own its data (but keep copy!)
dtstr = np.require(indtstr, dtype='U', requirements='O')
dtstr = dtstr.copy() if dtstr is indtstr else dtstr
# Replace leapsecond with a valid "59"
# Indices of every place that might be leap second
# Leap second is sec==60, must come at LEAST after YYMMDDHHMM, if
# being very terse, but this still will avoid YYYY-060
lsidx = np.char.rfind(dtstr, '60') >= 10
if lsidx.shape == ():
lsidx = lsidx.reshape((1,)) #atleast1d is only in new numpy
leapidx = np.transpose(np.nonzero(lsidx))
# Add offset to datetime value to get actual UTC,
# in integer microseconds.
offset = np.zeros(shape=dtstr.shape, dtype=np.uint32)
# Actual leap second indices (not just suspected)
realleap = []
for j, idx in enumerate(leapidx): # Should be short list, so loop it
# Get the index to scalar if necessary
i = tuple(idx) if dtstr.shape else ()
# The leap second must be preceded by at least 10 char (above),
# followed by either nothing or fractional seconds,
# preceded by 59 minutes (and optional separator)
# It must also not be preceded by a . (to avoid replacing
# 60 milliseconds with 59 milliseconds).
dtstr[i], count = re.subn(
r'^([^\.]{8,}59[^\d]?)60((?:\.\d+)?)$', r'\g<1>59\g<2>', dtstr[i])
# Doing this subtracted one second.
if count:
realleap.append(idx)
offset[i] = 1e6
# Cut index of leap seconds down to real ones.
leapidx = np.array(realleap)
# try a few special cases that are faster than dateutil.parser
strfmts = ['%Y-%m-%dT%H:%M:%S',
'%Y-%m-%dT%H:%M:%SZ',
'%Y-%m-%d',
'%Y%m%d',
'%Y%m%d %H:%M:%S']
if fmt not in strfmts:
strfmts.insert(0, fmt)
for strfmt in strfmts:
try:
UTC = np.frompyfunc(
lambda x: datetime.datetime.strptime(x, strfmt), 1, 1)(dtstr)
break
except ValueError:
continue
else:
UTC = np.frompyfunc(dup.parse, 1, 1)(dtstr)
isostr = np.vectorize(lambda x: x.strftime(fmt), otypes=['U'])(UTC)
# Check that leap seconds are actually valid
if len(leapidx):
# Day that ends in leap second *entry* (may not be leap second)
# Unbelievably these are read as floats, and other places rely on that.
leapsecday = np.array([
datetime.date(int(y), int(m), int(d))- datetime.timedelta(days=1)
for y, m , d in zip(year, mon, day)])
# Find only those leap seconds that are really changes
idx = np.nonzero(np.diff(np.concatenate(([0], secs))))[0]
leapsecday = leapsecday[idx]
if dtstr.shape == ():
if UTC.date() not in leapsecday:
raise ValueError('{} is not a valid leapsecond.'.format(
indtstr))
else:
utcday = np.frompyfunc(lambda x: x.date(), 1, 1)(UTC[leapidx])
# Last day w/leapsecond that comes before supposed leapsec day
closestday = np.clip(
np.searchsorted(leapsecday, utcday), None, len(leapsecday) - 1)
bad = utcday != leapsecday[closestday]
if bad.any():
raise ValueError('{} is not a valid leapsecond.'.format(
indtstr[leapidx[bad][0]]))
#Peg all leap seconds to the end of the previous second
for idx in leapidx:
i = tuple(idx) if dtstr.shape else ()
if not offset[i]:
continue
# The time string is off by one second.
if i == (): # Scalar input.
isostr = UTC.strftime(fmt.replace('%S', '60'))
us = UTC.microsecond
UTC = UTC + datetime.timedelta(microseconds=(1e6 - us - 1))
offset = us + 1
else:
isostr[i] = UTC[i].strftime(fmt.replace('%S', '60'))
us = UTC[i].microsecond
UTC[i] = UTC[i] + datetime.timedelta(microseconds=(1e6 - us - 1))
offset[i] = us + 1
return isostr, UTC, offset
[docs]def sec2hms(sec, rounding=True, days=False, dtobj=False):
"""Convert seconds of day to hours, minutes, seconds
Parameters
==========
sec : float
Seconds of day
Other Parameters
================
rounding : boolean
set for integer seconds
days : boolean
set to wrap around day (i.e. modulo 86400)
dtobj : boolean
set to return a timedelta object
Returns
=======
out : [hours, minutes, seconds] or datetime.timedelta
"""
if rounding:
sec = int(round(sec))
if not days:
if sec > 86400:
warnings.warn("Number of seconds > seconds in day. "
"Try days keyword.")
else:
sec %= 86400
if dtobj: # no need to do the computation
return datetime.timedelta(seconds=sec)
else:
hours = sec // 3600
minutes = ((sec - hours * 3600) // 60) % 60
seconds = sec % 60
return [hours, minutes, seconds]
def no_tzinfo(dt):
"""
take in an arraylike of datetime objects and return them without any tzinfo
Parameters
==========
dt : iterable
iterable of datetime.datetime objects
Returns
=======
out : list
list of datetime.datetime without tzinfo
"""
returnclass = type(dt)
try:
retval = [val.replace(tzinfo=None) for val in dt]
except TypeError: # was not an iterable, assume datetime
return dt.replace(tzinfo=None)
#special case: numpy ndarray - dmarray and masked array work, but not ndarray
if returnclass is not np.ndarray:
retval = returnclass(retval)
if hasattr(dt, 'attrs') and hasattr(retval, 'attrs'):
retval.attrs.update(dt.attrs)
return retval
else:
return np.asarray(retval)
[docs]def leapyear(year, numdays=False):
"""
return an array of boolean leap year,
a lot faster than the mod method that is normally seen
Parameters
==========
year : array_like
array of years
numdays : boolean (optional)
optionally return the number of days in the year
Returns
=======
out : numpy array
an array of boolean leap year, or array of number of days
Examples
========
>>> import numpy
>>> import spacepy.time
>>> spacepy.time.leapyear(numpy.arange(15)+1998)
[False, False, True, False, False, False, True, False, False,
False, True, False, False, False, True]
"""
year = np.asanyarray(year)
mask400 = (year % 400) == 0
mask100 = (year % 100) == 0
mask4 = (year % 4) == 0
isleap = (mask400 | mask4) & (~mask100 | mask400)
if numdays:
isleap = isleap.astype(int) + 365
return isleap
[docs]def randomDate(dt1, dt2, N=1, tzinfo=False, sorted=False):
"""
Return a (or many) random datetimes between two given dates
Convention used is dt1 <= rand < dt2. Leap second times will
not be returned.
Parameters
==========
dt1 : datetime.datetime
start date for the the random date
dt2 : datetime.datetime
stop date for the the random date
Other Parameters
================
N : int (optional)
the number of random dates to generate (defualt=1)
tzinfo : bool (optional)
maintain the tzinfo of the input datetimes (default=False)
sorted : bool (optional)
return the times sorted (default=False)
Returns
=======
out : datetime.datetime or numpy.ndarray of datetime.datetime
the new time for the next call to EventTimer
Examples
========
"""
if dt1.tzinfo != dt2.tzinfo:
raise ValueError('tzinfo for the input and output datetimes must match')
tt = Ticktock([dt1, dt2]).RDT
rnd_tn = np.random.uniform(tt[0], tt[1], size=N)
rnd_t = Ticktock(rnd_tn, dtype='RDT')
if sorted:
rnd_t.sort()
rnd_t = np.asarray([val.replace(tzinfo=dt1.tzinfo if tzinfo else None)
for val in rnd_t.UTC])
return rnd_t
def extract_YYYYMMDD(filename):
"""
go through a string and extract the first valid YYYYMMDD as a datetime
Parameters
==========
filename : str
string to parse for a YYYYMMDD format
Returns
=======
out : (None, datetime.datetime)
the datetime found in the string or None
"""
# return a datetime if there is one from YYYYMMDD
# be picky so don't match random numbers (1950-2049)
m = re.search(r"(19[5-9]|20[0-4])\d(0\d|1[0-2])([0-2]\d|3[01])",
os.path.basename(filename))
if not m:
return None
else:
return datetime.datetime.strptime(m.group(), '%Y%m%d')
def valid_YYYYMMDD(inval):
"""
if inval is valid YYYYMMDD return True, False otherwise
"""
if re.search(r"(19[5-9]|20[0-4])\d(0\d|1[0-2])([0-2]\d|3[01])",
inval):
return True
else:
return False
def _leapsgood(now, filetime, lastleap):
"""Determines if leap seconds are up-to-date
Parameters
----------
now : datetime.datetime
Current time (UTC assumed)
filetime : datetime.datetime
Timestamp (mtime) of the leapsecond file
lastleap : datetime.datetime
Last leapsecond in the file (really the moment after the leap)
Returns
-------
bool
True if leap second file is up-to-date, False if might not be.
"""
# There cannot be a leap second until AFTER the ls after the
# bulletin (e.g. once past 1 Jan, know the next possible is next 1 Jan)
goodto_mtime = datetime.datetime(
filetime.year + 1, 7 if filetime.month > 6 else 1, 1)
# The next possible leapsecond is 6mo after the previous known leap,
# which is (technically just before) 1 Jan or 1 July
goodto_ls = datetime.datetime(
lastleap.year + int(lastleap.month > 6),
1 if lastleap.month > 6 else 7, 1)
goodto = max(goodto_ls, goodto_mtime)
return now < goodto
def _read_leaps(oldstyle=False):
"""Read leapseconds in from spacepy tai-utc file
Populates module-global variables with leapsecond information:
secs, year, mon, day, TAIleaps.
Called on import of this module.
Other Parameters
----------------
oldstyle : bool
.. versionadded:: 0.2.3
Treat leapseconds as in SpacePy 0.2.2 (default False). Default is
to ignore the file contents through 1 Jan 1972 and use SpacePy's own
list of integral leapseconds, which uses the post-1972 standard
(add a leapsecond on January 1/July 1 if UTC - UT1 > 0.4s).
"""
global secs, year, mon, day, TAIleaps
# load current file
fname = os.path.join(spacepy.DOT_FLN, 'data', 'tai-utc.dat')
try:
with open(fname) as fh:
text = fh.readlines()
mtime = datetime.datetime(*time.gmtime(os.path.getmtime(fname))[:6])
except IOError:
warnings.warn('Cannot read leapsecond file. Use'
' spacepy.toolbox.update(leapsecs=True).')
text = [] # Use built-in pre-1972 leaps
mtime = None
# Some files have a "last checked" line at the top
if text and text[0].startswith('Checked'):
del text[0]
months = np.array(['JAN', 'FEB', 'MAR', 'APR', 'MAY', 'JUN',
'JUL', 'AUG', 'SEP', 'OCT', 'NOV', 'DEC'])
if not oldstyle: # Use internal integral leapsecond count until 1972
keep_idx = next((i for i, l in enumerate(text)
if int(l[:5]) > 1972
or int(l[:5]) == 1972 and l[6:9] == 'JUL'), len(text))
leaps = [(1959, 1, 36569), (1961, 1, 37300), (1963, 7, 38211),
(1965, 1, 38761), (1966, 7, 39307), (1967, 7, 39672),
(1968, 7, 40038), (1969, 7, 40403), (1970, 7, 40768),
(1971, 7, 41133)]
# 1972 Jan NOT a leapsecond in this formulation; TAI-UTC=10s at 71 Jul
text = [
' {Y} {M} 1 =JD {JD} TAI-UTC={L:12.7f} S '
'+ (MJD - 00000.) X 0.0000000 S ACTUAL\n'.format(
Y=l[0], M=months[l[1] - 1], JD=l[2] + 2400000.5, L=i + 1)
for i, l in enumerate(leaps)] \
+ text[keep_idx:]
secs = np.zeros(len(text))
year = np.zeros(len(text))
mon = np.zeros(len(text))
day = np.zeros(len(text))
for line, i in zip(text, np.arange(len(secs))):
# Round float seconds (0.5 always rounds up.)
secs[i] = int(float(line.split()[6]) + 0.5)
year[i] = int(line.split()[0])
mon[i] = int(np.where(months == line.split()[1])[0][0] + 1)
day[i] = int(line.split()[2])
# Check for out of date. The leap second bulletin comes every
# six months, and that contains information through the following
# leap second (end of June/Dec)
try:
utcnow = datetime.datetime.now(datetime.UTC).replace(tzinfo=None)
except AttributeError:
utcnow = datetime.datetime.utcnow()
if mtime is not None and spacepy.config['enable_old_data_warning'] \
and not _leapsgood(
utcnow, mtime,
datetime.datetime(int(year[-1]), int(mon[-1]), int(day[-1]))):
warnings.warn('Leapseconds may be out of date.'
' Use spacepy.toolbox.update(leapsecs=True)')
TAIleaps = np.zeros(len(secs))
TAItup = [''] * len(secs)
TAI0 = datetime.datetime(1958, 1, 1, 0, 0, 0, 0)
for i in np.arange(len(secs)):
TAItup[i] = datetime.datetime(int(year[i]), int(mon[i]), int(day[i])) - TAI0 + datetime.timedelta(
seconds=int(secs[i]) - 1)
TAIleaps[i] = TAItup[i].days * 86400 + TAItup[i].seconds + TAItup[i].microseconds / 1.e6
def _days1958(tai, leaps='rubber', midnight=False):
"""Calculate days and fractional days since 1958-01-01T12:00
This is basically a Julian Date but baselined from the start of TAI.
Since it is calculated from TAI, using this as day 0 maximizes the
resolution of the resulting values.
Parameters
==========
tai : sequence of float
TAI seconds (i.e. continuous SI seconds relative to 1958-01-01T00:00)
leaps : str, optional
How to treat days with leapseconds. Since the Julian Date runs
noon (inclusive) to noon (exclusive), this affects the back
half of the date with the leapsecond, and the first half of the
next. Accepted values are:
rubber
Consider these days to be 86401 seconds long and thus treat
each second as a slightly smaller fraction of the day,
so that all times are represented and evently spaced within
the day. I.e. the day is "stretched" across more seconds, by
analogy with the "rubber second" of 1960-1972. (default)
drop
Treate time as a flow of SI seconds that is suspended during
leapseconds, i.e. leapsecond time does not exist. Time during
leap seconds is pinned to the last microsecond of the
previous second.
continuous
Treat time as a continuous flow of SI seconds with days always
86400 seconds long. This is the proper handling for true
Julian Dates, i.e. JD(TAI), as recommended by IAU General Assembly
XXIII, resolution B1.
Returns
=======
sequence of float
Days, including fraction, relative to 1958-01-01T12:00
Other parameters
================
midnight : bool, optional
Start the day at midnight instead of noon. This affects the allocation
of leap seconds, and of course days are relative to 1958-01-01T00:00
"""
off = 0. if midnight else 43200. # Offset from midnight
# Shift to time-since-noon, if desired (also makes copy), call delta-TAI
dtai = np.require(tai, dtype=np.float64) - off
leap_dtai, taiutc = _changed_leaps()
leap_dtai -= off # delta-TAI of start of leap second
if leaps in ('rubber', 'drop'):
# Index of leapsecond equal to or before each time record
lidx = np.searchsorted(leap_dtai, dtai, side='right') - 1
elif leaps != 'continuous':
raise ValueError('leaps handling {} not recognized.'.format(leaps))
if leaps == 'rubber':
# d-TAI of start-of-day (noon or midnight) before/after each leapsecond
# because leapseconds always start at 23:59:60 (43200s after noon).
if midnight:
daystart_before_leap = leap_dtai - 86400
daystart_after_leap = leap_dtai + 1
else:
daystart_before_leap = leap_dtai - 43200
daystart_after_leap = leap_dtai + 43201
# Closest leapsecond-day-start before record.
# May be greater than lidx, if near but before leapsecond
ldidx = np.searchsorted(daystart_before_leap, dtai, side='right') - 1
# All records that happen on leap second days.
leap_sec_day = (daystart_before_leap[ldidx] <= dtai) \
& (dtai < daystart_after_leap[ldidx])
# Save SSD on leap second days, about to be destroyed
if leap_sec_day.shape == (): # Scalar
ssd_leap_sec_day = dtai - daystart_before_leap[ldidx]
else:
ssd_leap_sec_day = dtai[leap_sec_day] \
- daystart_before_leap[ldidx[leap_sec_day]]
# Destroy leap seconds, so days always break at 86400s
dtai -= taiutc[lidx]
elif leaps == 'drop':
# Where in a leapsecond, pin to previous second
inleap = dtai - leap_dtai[lidx] < 1
if inleap.shape == (): # Scalar
if inleap:
dtai = np.floor(dtai) - .000001
lidx -= 1 # Associated with previous TAI - UTC
else:
dtai[inleap] = np.floor(dtai[inleap]) - .000001
# Already subtracted ~1sec, now associated with previous TAI - UTC
lidx[inleap] -= 1
# Remove all of the TAI seconds that "disappeared".
dtai -= taiutc[lidx]
day = np.floor(dtai / 86400)
ssd = dtai - day * 86400 # Mod does wrong thing if negative.
if leaps == 'rubber':
# Patch back in the SSD on leap-second days.
if leap_sec_day.shape == (): # Scalar
if leap_sec_day:
ssd = ssd_leap_sec_day
else:
ssd[leap_sec_day] = ssd_leap_sec_day
daylen = np.choose(leap_sec_day, (86400., 86401.))
else:
daylen = 86400
return day + ssd / daylen
def _days1958totai(days, leaps='rubber', midnight=False):
"""Calculate TAI from days and fractional days since 1958-01-01T12:00
Input is basically a Julian Date but baselined from the start of TAI.
Since it is calculated from TAI, using this as day 0 maximizes the
resolution of the resulting values.
Parameters
==========
days : sequence of float
Days, including fraction, relative to 1958-01-01T12:00
leaps : str, optional
How to treat days with leapseconds. Since the Julian Date runs
noon (inclusive) to noon (exclusive), this affects the back
half of the date with the leapsecond, and the first half of the
next. Accepted values are:
rubber
Consider these days to be 86401 seconds long and thus treat
each second as a slightly smaller fraction of the day,
so that all times are represented and evently spaced within
the day. I.e. the day is "stretched" across more seconds, by
analogy with the "rubber second" of 1960-1972. (default)
drop
Treate time as a flow of SI seconds that is suspended during
leapseconds, i.e. leapsecond time does not exist. Time during
leap seconds is not recovered (no output time during leaps.)
continuous
Treat time as a continuous flow of SI seconds with days always
86400 seconds long. This is the proper handling for true
Julian Dates, i.e. JD(TAI), as recommended by IAU General Assembly
XXIII, resolution B1.
Returns
=======
sequence of float
TAI seconds (i.e. continuous SI seconds relative to 1958-01-01T00:00)
Other parameters
================
midnight : bool, optional
Start the day at midnight instead of noon. This affects the allocation
of leap seconds, and of course `days` are relative to 1958-01-01T00:00
"""
days = np.require(days, dtype=np.float64)
off = 0. if midnight else 43200. # Offset from midnight
if leaps == 'continuous': # Very simple case.
return days * 86400 + off
elif leaps not in ('rubber', 'drop'):
raise ValueError('leaps handling {} not recognized.'.format(leaps))
leap_tai, taiutc = _changed_leaps()
leap_dtai = leap_tai - off # delta-TAI of start of leap second
# Days with leap second. Leap second is always late in day: end
# of day if doing midnight-to-midnight, halfway if noon-to-noon.
leap_day = np.floor((leap_dtai - taiutc) / 86400)
# Closest leapsecond-day before record.
ldidx = np.searchsorted(leap_day, days) - 1
# All records that happen on leap second days.
leap_sec_day = (ldidx > 0) \
& (leap_day[ldidx] <= days) \
& (days < leap_day[ldidx] + 1)
if leaps == 'rubber':
daylen = np.choose(leap_sec_day, (86400., 86401.))
else:
daylen = 86400.
# Naive TAI at start of day (no leapsecond corrections).
dayint = np.floor(days)
daystart = dayint * 86400
# Seconds from the start of naive day.
ssd = (days - dayint) * daylen # Mod does wrong thing if negative
# Index TAIUTC for every input. Start of day w/LS is still previous value.
taiutcidx = ldidx - np.require(leap_sec_day, dtype=np.intp)
# Keep small number adds together: ssd and leapseconds.
taiout = daystart + (ssd + off + taiutc[taiutcidx])
if leaps == 'drop':
# Any times after leap-second skip need an extra second.
taiutcidx += np.require(leap_sec_day & (taiout >= leap_tai[ldidx]),
dtype=np.intp)
# Recalculate to keep small-number addition together
taiout = daystart + (ssd + off + taiutc[taiutcidx])
return taiout
def _changed_leaps():
"""Find only those times where leap seconds actually changed
There are leap second records where there is no actual change
in leap seconds, and there isn't a record for TAI-UTC == 0; this
adds a record (where the TAI of the leap second time is -inf) and
eliminated those with no actual change.
Returns
=======
leap_tai : sequence of float
TAI of the start of every leap second.
taiutc : sequence of float
TAI - UTC at the end of the leap second.
"""
# Find only those leap seconds that are really changes
idx = np.nonzero(np.diff(np.concatenate(([0], secs))))[0]
leap_tai = TAIleaps[idx] # TAI of start of leap second
taiutc = secs[idx] # TAI - UTC after leap second (same index as leap_tai)
# Add fake TAI - UTC = 0 at the Big Bang
leap_tai = np.concatenate(([-np.inf], leap_tai))
taiutc = np.concatenate(([0], taiutc))
return leap_tai, taiutc
def _tai_naive_to_real(tai):
"""Convert naive TAI to real TAI
Convert a TAI on a continuous timescale that skips over leapseconds
and is unaware of calendar conversion to actual TAI, which includes
leapseconds and is continuous across the Gregorian conversion (naive
has a gap, i.e. dates it can represent that don't exist.)
Parameters
==========
tai : sequence of float
Naive TAI
Returns
=======
tai : sequence of float
TAI
"""
# This is the ACTUAL TAI and TAI-UTC at the end of that TAI
leap_tai, taiutc = _changed_leaps()
# Naive TAI and index that corresponds to TAI - UTC
naive_leap_tai = leap_tai - taiutc + 1
taiutcidx = np.searchsorted(naive_leap_tai, tai, side='right') - 1
realtai = tai + taiutc[taiutcidx]
# Anything before 1582-10-5 has TAI ten days later than the
# naive conversion, because naive has ten days that are not in TAI.
realtai[realtai < -11840601600.0] += 864000
return realtai
def _tai_real_to_naive(tai):
"""Convert naive TAI to actual TAI
Convert actual TAI, which includes leapseconds and is continuous
across the Gregorian calendar conversion, to naive TAI, which skips
over leapseconds and has times in the calendar conversion that
do not actually exist.
Parameters
==========
tai : sequence of float
TAI
Returns
=======
tai : sequence of float
Naive TAI
"""
# ACTUAL TAI and TAI-UTC at the end of that TAI
leap_tai, taiutc = _changed_leaps()
# Points to largest leap-TAI less-than input TAI, thus also TAI-UTC
lidx = np.searchsorted(leap_tai, tai, side='right') - 1
# Records in a leap second
inleap = tai < leap_tai[lidx] + np.diff(taiutc)[lidx - 1]
naive_tai = np.choose(inleap, (
tai - taiutc[lidx], # Just subtract off LS
np.floor(tai) + (.999 - taiutc[lidx]) # Peg to end of sec
))
# Anything before 1582-10-15 needs to skip 10 CDF days backward,
# since naive has ten days that are not in TAI
naive_tai[tai < -11839737600.0] -= 864000
return naive_tai
_read_leaps()
