Generator

What each Newton step asked of its linear solve, and what the solve cost, under the adaptive policy

One function in the sequence library, called 3 times across 1 essay. Below: what it draws at its defaults, what it draws at every value an essay asks for, the 7 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 what each newton step asked of its linear solve, and what the solve cost, under the adaptive policy. The lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 0.9 and costs 1 iteration, and the last asks for 0.0042 and costs 271. The whole solve costs 1009 inner iterations across 10 Newton steps and ends at a relative residual of 3.37·10⁻¹¹.

forcing-trail is one function in lib/figures/sequence.js — sequences — a solve inside an outer loop, and the accuracy the loop throws away. 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.

What each Newton step asked of its linear solve, and what the solve cost, under the adaptive policyThe lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 0.9 and costs 1 iteration, and the last asks for 0.0042 and costs 271. The whole solve costs 1009 inner iterations across 10 Newton steps and ends at a relative residual of 3.37·10⁻¹¹.0123456789101110⁻¹⁵10⁻¹²10⁻⁹10⁻⁶10⁻³110³Newton steptolerance asked for, and iterations paiditerations paidtolerance asked forouter residualthe adaptive policy, step by stepNewton steps10inner iterations, total1009first step's cost1last step's cost271final outer residual3.4·10⁻¹¹the rule reads the last two residualsand asks for nothing it cannot use

The lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 0.9 and costs 1 iteration, and the last asks for 0.0042 and costs 271. The whole solve costs 1009 inner iterations across 10 Newton steps and ends at a relative residual of 3.37·10⁻¹¹.

which: "adaptive"

The arguments are the ones A tolerance that reads its own residual passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

What each Newton step asked of its linear solve, and what the solve cost, under the adaptive policyThe lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 0.9 and costs 1 iteration, and the last asks for 0.0042 and costs 271. The whole solve costs 1009 inner iterations across 10 Newton steps and ends at a relative residual of 3.37·10⁻¹¹.0123456789101110⁻¹⁵10⁻¹²10⁻⁹10⁻⁶10⁻³110³Newton steptolerance asked for, and iterations paiditerations paidtolerance asked forouter residualthe adaptive policy, step by stepNewton steps10inner iterations, total1009first step's cost1last step's cost271final outer residual3.4·10⁻¹¹the rule reads the last two residualsand asks for nothing it cannot use

The lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 0.9 and costs 1 iteration, and the last asks for 0.0042 and costs 271. The whole solve costs 1009 inner iterations across 10 Newton steps and ends at a relative residual of 3.37·10⁻¹¹.

which: "tight"

The arguments are the ones A tolerance that reads its own residual passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

What each Newton step asked of its linear solve, and what the solve cost, under the tight policyThe lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 10⁻¹⁴ and costs 1775 iterations, and the last asks for 10⁻¹⁴ and costs 1128. The whole solve costs 9358 inner iterations across 9 Newton steps and ends at a relative residual of 1.43·10⁻¹³.01234567891010⁻¹⁵10⁻¹²10⁻⁹10⁻⁶10⁻³110³Newton steptolerance asked for, and iterations paiditerations paidtolerance asked forouter residualthe tight policy, step by stepNewton steps9inner iterations, total9358first step's cost1775last step's cost1128final outer residual1.4·10⁻¹³the rule reads the last two residualsand asks for nothing it cannot use

The lower series is the tolerance handed to the inner solve at each step and the upper one is the number of conjugate gradient iterations it took. Under the adaptive rule the first step asks for 10⁻¹⁴ and costs 1775 iterations, and the last asks for 10⁻¹⁴ and costs 1128. The whole solve costs 9358 inner iterations across 9 Newton steps and ends at a relative residual of 1.43·10⁻¹³.

What it checked while drawing

Every figure above checked its own claims on the way to being drawn, and a claim that failed would have stopped the picture rather than shipped a wrong one. Those checks 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.

7 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.

a conditioning the SPD construction can hold

a forcing policy the trail is drawn for

a size the dense factorisations are affordable at

an outer tolerance that is a relative residual

matmul shapes agree

one tolerance and one cost for every step

the run reaches the outer tolerance

Against the rule

It draws a decomposition and prints its residual. It calls orderSweep, orderSweep, and every figure above carries the badge — which residualcheck verifies by looking for it in the emitted SVG rather than by finding the call that builds one. A badge that is constructed and then left out of the body is the failure that check exists for.

Across the library: the rule bites on 217 of 397 generators — 199 print a residual and 18 are exempt with a published reason; 180 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