`whylogs.core.statistics.thetasketch`¶

Module Contents¶

Classes¶

ThetaSketch

A sketch for approximate cardinality tracking.

Functions¶

`_copy_union`(union)
`numbers_summary`(sketch: ThetaSketch, num_std_devs=1)	Generate a summary protobuf message from a thetasketch based on numeric

whylogs.core.statistics.thetasketch._copy_union(union)¶

class whylogs.core.statistics.thetasketch.ThetaSketch(theta_sketch=None, union=None, compact_theta=None)¶

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(self, value)¶

Update the statistics tracking

Parameters: value (object) – Value to follow

merge(self, other)¶

Merge another ThetaSketch with this one, returning a new object

Parameters: other (ThetaSketch) – Other theta sketch
Returns: new – New theta sketch with merged statistics
Return type: ThetaSketch

get_result(self)¶

Generate a theta sketch

Returns: compact_sketch – Read-only compact theta sketch with full statistics.
Return type: datasketches.compact_theta_sketch

serialize(self)¶

Serialize this object.

Note that serialization only preserves the object approximately.

Returns: msg – Serialized to bytes
Return type: bytes

static deserialize(msg: bytes)¶

Deserialize from a serialized message.

msg

Parameters

msg (bytes) –

Serialized object. can be a serialized version of:

ThetaSketch
datasketches.update_theta_sketch,
datasketches.compact_theta_sketch

Returns

sketch – ThetaSketch object

Return type

ThetaSketch

to_summary(self, num_std_devs=1)¶

Generate a summary protobuf message

Parameters: num_std_devs (float) – For estimating bounds
Returns: summary – Summary protobuf message
Return type: UniqueCountSummary

whylogs.core.statistics.thetasketch.numbers_summary(sketch: ThetaSketch, num_std_devs=1)¶

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