op-agg-set-intersection - Pulse Documentation

name: op-agg-set-intersection
description: Bitwise-AND a set field across rows; returns labels for every bit set in every contributing row.
kind: operator
category: AGG
operator: AGG_SET_INTERSECTION
type: reference
applies_to: process, compose, predict
examples_tags: [cardinality-analysis, cohort-analysis]

Use when

For a multi-select field, the options chosen by every row, over all rows or per group.

Questions it answers:

Which brands did every respondent in this segment recognise?
Which features does every customer on a plan use?

Use something else:

AGG_SET_UNION when you want every option chosen by anyone.
AGG_SET_FREQUENCY when you want how many rows chose each option.

Params

None.

Inputs

Param	Accepted field types
`Field`	any set rung — `set_u8`, `set_u16`, `set_u32`, `set_u64`, `set_u128`, `set_u256`

Output

Rich []string — resolved dictionary labels. Scalar fallback = popcount of the intersection mask.

Components

Universal floor {n, n_null} plus operator-specific:

Key	Type	Notes
`mask_intersection`	`[]uint64`	Bitwise AND across contributing rows; 4 little-endian words, `words[0]` = bits 0-63
`popcount`	int	Bits set in `mask_intersection`
`labels`	`[]string`	Resolved dictionary labels

Mergeability: Mergeable per-chunk
Margin reducibility: NOT margin-reducible — crosstab margins recompute from raw rows

Gotchas

AND across all rows ≠ AND across cells; do NOT pool margins.
One row with all-zero bits → empty intersection for the group.

See

pulse_examples_search tags=[cardinality-analysis]
Skills: aggregation-design, cohort-schema-design, response-components

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