Module differential_dataflow::dynamic::pointstamp

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A timestamp type as in Naiad, where a vector of timestamps of different lengths are comparable.

This type compares using “standard” tuple logic as if each timestamp were extended indefinitely with minimal elements.

The path summary for this type allows run-time rather than type-driven iterative scopes. Each summary represents some journey within and out of some number of scopes, followed by entry into and iteration within some other number of scopes.

As a result, summaries describe some number of trailing coordinates to truncate, and some increments to the resulting vector. Structurally, the increments can only be to one non-truncated coordinate (as iteration within a scope requires leaving contained scopes), and then to any number of appended default coordinates (which is effectively just setting the coordinate).


  • A sequence of timestamps, partially ordered by the product order.
  • Stack for PointStamp. Part of Columnation implementation.
  • Describes an action on a PointStamp: truncation to length followed by actions.