Class Segment

source code

         object --+    
                  |    
table.Table.RowType --+
                      |
                     Segment

Known Subclasses:

• SegmentSum

Example:

>>> x = Segment()
>>> x.start = LIGOTimeGPS(0)
>>> x.end = LIGOTimeGPS(10)
>>> x.segment
segment(LIGOTimeGPS(0, 0), LIGOTimeGPS(10, 0))
>>> x.segment = None
>>> print(x.segment)
None
>>> print(x.start)
None
>>> # non-LIGOTimeGPS times are converted to LIGOTimeGPS
>>> x.segment = (20, 30.125)
>>> x.end
LIGOTimeGPS(30, 125000000)
>>> # initialization from a tuple or with arguments
>>> Segment((20, 30)).segment
segment(LIGOTimeGPS(20, 0), LIGOTimeGPS(30, 0))
>>> Segment(20, 30).segment
segment(LIGOTimeGPS(20, 0), LIGOTimeGPS(30, 0))
>>> # use as a segment object in segmentlist operations
>>> from glue import segments
>>> x = segments.segmentlist([Segment(0, 10), Segment(20, 30)])
>>> abs(x)
LIGOTimeGPS(20, 0)
>>> y = segments.segmentlist([Segment(5, 15), Segment(25, 35)])
>>> abs(x & y)
LIGOTimeGPS(10, 0)
>>> abs(x | y)
LIGOTimeGPS(30, 0)
>>> 8.0 in x
True
>>> 12 in x
False
>>> Segment(2, 3) in x
True
>>> Segment(2, 12) in x
False
>>> segments.segment(2, 3) in x
True
>>> segments.segment(2, 12) in x
False
>>> # make sure results are segment table row objects
>>> segments.segmentlist(map(Segment, x & y))   # doctest: +ELLIPSIS
[<glue.ligolw.lsctables.Segment object at 0x...>, <glue.ligolw.lsctables.Segment object at 0x...>]

This implementation uses a non-standard extension to encode infinite values for boundaries: the second and nanosecond components are both set to 0x7FFFFFFF or 0xFFFFFFFF to indicate positive resp. negative infinity. For this reason, "denormalized" LIGOTimeGPS objects (objects whose nanoseconds fields contain values exceeding +/-999999999) are disallowed for use with this class.

Example:

>>> x = Segment()
>>> # OK
>>> x.start = -segments.infinity()
>>> # also OK
>>> x.start = float("-inf")
>>> # infinite boundaries always returned as segments.infinity
>>> # instances
>>> x.start
-infinity
>>> x.end = float("+inf")
>>> x.segment
segment(-infinity, infinity)