whylogs.core.statistics.thetasketch

ThetaSketch Objects#

class ThetaSketch()

A sketch for approximate cardinality tracking.

A wrapper class for datasketches.update_theta_sketch which implements merging for updatable theta sketches.

Currently, datasketches only implements merging for compact (read-only) theta sketches.

 | update(value)

Update the statistics tracking

value : object Value to follow

 | merge(other)

Merge another ThetaSketch with this one, returning a new object

other : ThetaSketch Other theta sketch

new : ThetaSketch New theta sketch with merged statistics

 | get_result()

Generate a theta sketch

compact_sketch : datasketches.compact_theta_sketch Read-only compact theta sketch with full statistics.

 | serialize()

Serialize this object.

Note that serialization only preserves the object approximately.

msg : bytes Serialized to bytes

 | @staticmethod
 | deserialize(msg: bytes)

Deserialize from a serialized message.

msg

msg : bytes Serialized object. can be a serialized version of:

    * ThetaSketch
    * datasketches.update_theta_sketch,
    * datasketches.compact_theta_sketch

sketch : ThetaSketch ThetaSketch object

 | to_summary(num_std_devs=1)

Generate a summary protobuf message

num_std_devs : float For estimating bounds

summary : UniqueCountSummary Summary protobuf message

numbers_summary(sketch: ThetaSketch, num_std_devs=1)

Generate a summary protobuf message from a thetasketch based on numeric values

sketch

num_std_devs : float For estimating bounds

summary : UniqueCountSummary Summary protobuf message