Column Rule

What it does

Answers one rule per coin: at least or at most a fixed level, or a place among the other coins at that instant — the top or bottom N, or N percent. The answer is 1 or 0, and nothing at all for a coin with no value.

What happens

Used only inside a Universe. It runs at the universe's refresh or pick instants over every allowed coin, using only data that had closed by then, and its wires carry coin sets, per-coin columns or selections rather than one value per bar.

When to use

Whenever a number measure is used to keep coins out rather than to order them. Wiring a number straight onto a filter's mask means "not exactly zero", so a momentum of -0.3 would pass.

Gotchas

• A count rule takes a whole number of coins; a percent rule takes a value in (0, 100].
• A tie at the cut passes together, so a top-20 rule can keep 22 coins when three are level at twentieth — it never splits equal coins by an arbitrary order.
• The percent is of the coins that have a value, not of the whole coin set.