183 lines
5.0 KiB
Python
183 lines
5.0 KiB
Python
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"""Duration module."""
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import operator
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class Duration(object):
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"""Class Duration in development.
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"""
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allowed = ["ET", "UTC"]
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def __init__(self, frame, seconds):
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"""Create a new Duration object.
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= ERROR CONDITIONS
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- If the input frame is not in the allowed list, an error is thrown.
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= INPUT VARIABLES
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- frame The frame of the duration. Must be 'ET' or 'UTC'
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- seconds The number of seconds in the Duration.
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"""
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if frame not in self.allowed:
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msg = "Input frame '%s' is not one of the supported frames of %s" \
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% (frame, str(self.allowed))
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raise ValueError(msg)
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self._frame = frame
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self._seconds = seconds
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def frame(self):
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"""Return the frame the duration is in."""
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return self._frame
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def __abs__(self):
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"""Return the absolute value of the duration."""
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return Duration(self._frame, abs(self._seconds))
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def __neg__(self):
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"""Return the negative value of this Duration."""
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return Duration(self._frame, -self._seconds)
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def seconds(self):
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"""Return the number of seconds in the Duration."""
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return self._seconds
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def __bool__(self):
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return self._seconds != 0
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def __eq__(self, rhs):
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return self._cmp(rhs, operator.eq)
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def __ne__(self, rhs):
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return self._cmp(rhs, operator.ne)
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def __lt__(self, rhs):
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return self._cmp(rhs, operator.lt)
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def __le__(self, rhs):
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return self._cmp(rhs, operator.le)
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def __gt__(self, rhs):
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return self._cmp(rhs, operator.gt)
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def __ge__(self, rhs):
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return self._cmp(rhs, operator.ge)
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def _cmp(self, rhs, op):
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"""Compare two Durations.
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= INPUT VARIABLES
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- rhs The Duration to compare against.
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- op The function to do the comparison
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= RETURN VALUE
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- Returns op(self, rhs)
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"""
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self.checkSameFrame(rhs, "compare")
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return op(self._seconds, rhs._seconds)
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def __add__(self, rhs):
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"""Add two Durations.
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= ERROR CONDITIONS
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- If the input rhs is not in the same frame, an error is thrown.
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= INPUT VARIABLES
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- rhs The Duration to add.
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= RETURN VALUE
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- Returns the sum of ourselves and the input Duration.
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"""
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# Delay-load due to circular dependencies.
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import matplotlib.testing.jpl_units as U
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if isinstance(rhs, U.Epoch):
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return rhs + self
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self.checkSameFrame(rhs, "add")
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return Duration(self._frame, self._seconds + rhs._seconds)
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def __sub__(self, rhs):
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"""Subtract two Durations.
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= ERROR CONDITIONS
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- If the input rhs is not in the same frame, an error is thrown.
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= INPUT VARIABLES
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- rhs The Duration to subtract.
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= RETURN VALUE
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- Returns the difference of ourselves and the input Duration.
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"""
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self.checkSameFrame(rhs, "sub")
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return Duration(self._frame, self._seconds - rhs._seconds)
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def __mul__(self, rhs):
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"""Scale a UnitDbl by a value.
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= INPUT VARIABLES
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- rhs The scalar to multiply by.
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= RETURN VALUE
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- Returns the scaled Duration.
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"""
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return Duration(self._frame, self._seconds * float(rhs))
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def __rmul__(self, lhs):
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"""Scale a Duration by a value.
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= INPUT VARIABLES
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- lhs The scalar to multiply by.
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= RETURN VALUE
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- Returns the scaled Duration.
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"""
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return Duration(self._frame, self._seconds * float(lhs))
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def __div__(self, rhs):
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"""Divide a Duration by a value.
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= INPUT VARIABLES
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- rhs The scalar to divide by.
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= RETURN VALUE
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- Returns the scaled Duration.
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"""
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return Duration(self._frame, self._seconds / rhs)
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def __rdiv__(self, rhs):
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"""Divide a Duration by a value.
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= INPUT VARIABLES
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- rhs The scalar to divide by.
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= RETURN VALUE
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- Returns the scaled Duration.
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"""
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return Duration(self._frame, rhs / self._seconds)
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def __str__(self):
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"""Print the Duration."""
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return "%g %s" % (self._seconds, self._frame)
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def __repr__(self):
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"""Print the Duration."""
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return "Duration('%s', %g)" % (self._frame, self._seconds)
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def checkSameFrame(self, rhs, func):
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"""Check to see if frames are the same.
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= ERROR CONDITIONS
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- If the frame of the rhs Duration is not the same as our frame,
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an error is thrown.
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= INPUT VARIABLES
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- rhs The Duration to check for the same frame
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- func The name of the function doing the check.
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"""
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if self._frame != rhs._frame:
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msg = "Cannot %s Duration's with different frames.\n" \
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"LHS: %s\n" \
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"RHS: %s" % (func, self._frame, rhs._frame)
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raise ValueError(msg)
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