How many q-grams an occurrence must still share, m = 24

How many q-grams an occurrence must still share, m = 24

Each cell is t = m + 1 − q(k+1): the number of q-grams a window must share with the pattern before it is worth verifying. The shaded cells are where t has reached zero or below, which is a demand of nothing — the filter proposes every window and has stopped being a filter. Nothing here is measured: the collapse is arithmetic, it is known before a text is read, and it happens at q(k+1) = m + 1.

Drawn at 700 × 318, wide on the page. Everything above is what qgram-filter returns with no arguments; the caption is the generator's own, computed from the numbers in the drawing rather than written beside it.

4 essays call qgram-filter. The drawing above is what it returns with no arguments at all; every call below passes it something, because a placement that passes nothing draws whichever member of the family the generator happens to default to rather than the one its essay argues about — which is what optcheck and figfill exist to catch.