Bits per symbol on words from a fixed vocabulary, 16,384 symbols

Bits per symbol on words from a fixed vocabulary, 16,384 symbols

The dashed line is the zeroth-order entropy of this stream, 3.892 bits per symbol: the floor for any coder that gives each symbol a code and looks at nothing else. Huffman and arithmetic coding are both such coders and neither is under it. The dictionary coders are not, and LZSS (window 4096) and LZ78 finish below it — which is not a violation of anything, because the line is the floor for a different model than the one they use.

Drawn at 700 × 302, wide on the page. Everything above is what coder-gap returns with no arguments; the caption is the generator's own, computed from the numbers in the drawing rather than written beside it.

3 essays call coder-gap. 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.