Four prices for one set of marked rows

Four prices for one set of marked rows

The same 513 marked rows out of 16,385, held four ways, at a sampling rate of one in 32. The plain vector spends one bit a row and is 19,475 bits. Elias-Fano splits each position into a 4-bit low part and a high part written in unary, and is 3,905 — 20.1% of the plain vector. Compressed blocks reach 4,557, which at this density is close but not equal. The fourth row is not a structure: it is the accounting this collection has charged for Elias-Fano since the repetition strand, and it is 314 bits under the built object because it omits the directory a select needs.

Drawn at 700 × 226, wide on the page. Everything above is what sparse-marks returns with no arguments; the caption is the generator's own, computed from the numbers in the drawing rather than written beside it.

8 essays call sparse-marks. 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.