Generator

bound-tightness

One function in the interval library, called 4 times across 3 essays. Below: what it draws at its defaults, what it draws at every value an essay asks for, the 10 claims it put to the test while drawing them, and where it stands against the rule this site is named for.

At its defaults it draws the proved bound against the error it bounds, at 24 significand bits. Two curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 9.949 to 23.12 times. Past n = 5 the method refuses to return a bound at all.

bound-tightness is one function in lib/figures/interval.js — intervals — a bound that is proved rather than measured, and what proving it costs. Everything below came out of it during this build, at arguments taken from the essays rather than invented for this page. A figure here is the figure a reader meets in an essay, and if the generator changes, this page changes with it.

At its defaults

Drawn even though every essay passes arguments — which on this site is every essay, at 100% of placements since the standard pass. A default nothing exercises is a trap for the next essay to call this with none, and this is the page where a default that has drifted from the figures around it becomes visible.

The proved bound against the error it bounds, at 24 significand bitsTwo curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 9.949 to 23.12 times. Past n = 5 the method refuses to return a bound at all.345678910111210⁻⁵10⁻³10⁻¹Hilbert size nerrorrefusedrefusedrefusedrefusedrefusedthe proved boundthe actual errorbound ÷ errorslack at n = 313slack at n = 423slack at n = 59.9the error is known, not estimatedthe exact answer is the integers 1 … n

Two curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 9.949 to 23.12 times. Past n = 5 the method refuses to return a bound at all.

bits: 24

The arguments are the ones A bound that is proved passes. A value drawn at the generator's defaults instead would be a picture no essay asked for and no assertion has been run against.

The proved bound against the error it bounds, at 24 significand bitsTwo curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 9.949 to 23.12 times. Past n = 5 the method refuses to return a bound at all.345678910111210⁻⁵10⁻³10⁻¹Hilbert size nerrorrefusedrefusedrefusedrefusedrefusedthe proved boundthe actual errorbound ÷ errorslack at n = 313slack at n = 423slack at n = 59.9the error is known, not estimatedthe exact answer is the integers 1 … n

Two curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 9.949 to 23.12 times. Past n = 5 the method refuses to return a bound at all.

bits: 32

The arguments are the ones A bound that is proved passes. A value drawn at the generator's defaults instead would be a picture no essay asked for and no assertion has been run against.

The proved bound against the error it bounds, at 32 significand bitsTwo curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 8.174 to 2822 times. Past n = 7 the method refuses to return a bound at all.345678910111210⁻⁷10⁻⁵10⁻³10⁻¹Hilbert size nerrorrefusedrefusedrefusedthe proved boundthe actual errorbound ÷ errorslack at n = 38.2slack at n = 419slack at n = 520slack at n = 616slack at n = 72822the error is known, not estimatedthe exact answer is the integers 1 … n

Two curves against the Hilbert size on a logarithmic vertical axis: the error the computation actually made, which is known because the exact answer is the integers by construction, and the bound proved for it in interval arithmetic. The bound is above the error at every size, by 8.174 to 2822 times. Past n = 7 the method refuses to return a bound at all.

What it checked while drawing

Every figure above asserted its own claims on the way to being drawn, and a claim that failed would have failed the build rather than drawn a wrong picture. Those assertions used to leave no trace at all: a passing one returned true and the only evidence the figure had checked anything was that nothing crashed. The list below is what they actually said, collected by running this generator with an observer installed — not a description of what it is believed to check.

10 distinct claims across 3 sets of arguments, grouped below by shape — because most of them are one sentence with a different number in it, and how many separate times that sentence was put to the test is the informative part.

the bound holds at n = 3 — asserted 5 times

a precision the boundary is inside the drawn sizes at

and refuses at least one

and the bound it returns is not uselessly loose

LU is for square matrices

the method verifies at least two of these

Against the rule

The rule does not apply to it. It factorises nothing, so there is no residual it could be withholding. That is worth stating rather than leaving blank: a site that reported the rule as satisfied by every generator would be counting mostly generators the rule never reached.

Across the library: the rule bites on 52 of 99 generators — 37 print a residual and 15 are exempt with a published reason; 47 factorise nothing. Read from lib/residual-rule.js, which is the same body the gate enforces from, and the gate's last check fails the build if this page and it disagree about any generator.

Where it is called

Changing this generator changes every figure on this list. That is what makes the list worth publishing rather than keeping in a check script.

The whole library · All essays · What must fail