Generator

szego-approach

One function in the structure library, called 6 times across 3 essays. Below: what it draws at its defaults, what it draws at every value an essay asks for, the 14 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 κ of the ρ = 0.8 toeplitz family, against the limit it never reaches. The condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.8, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 81 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 98.9% of it at n = 128.

szego-approach is one function in lib/figures/structure.js — structure — the matrix that is one row, and the solver that cannot see it. 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.

κ of the ρ = 0.8 Toeplitz family, against the limit it never reachesThe condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.8, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 81 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 98.9% of it at n = 128.10¹10²10²size ncondition numberlimit 81measureda limit, as a fraction of itselfreached at n = 1280.99still to go0.011κ at n = 8, as a fraction0.52every point is below the line and none of them is on itthe limit is not a value

The condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.8, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 81 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 98.9% of it at n = 128.

rho: 0.8

The arguments are the ones A limit the matrix never reaches 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.

κ of the ρ = 0.8 Toeplitz family, against the limit it never reachesThe condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.8, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 81 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 98.9% of it at n = 128.10¹10²10²size ncondition numberlimit 81measureda limit, as a fraction of itselfreached at n = 1280.99still to go0.011κ at n = 8, as a fraction0.52every point is below the line and none of them is on itthe limit is not a value

The condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.8, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 81 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 98.9% of it at n = 128.

rho: 0.95

The arguments are the ones A limit the matrix never reaches 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.

κ of the ρ = 0.95 Toeplitz family, against the limit it never reachesThe condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.95, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 1521 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 87.9% of it at n = 128.10¹10²10²10³size ncondition numberlimit 1521measureda limit, as a fraction of itselfreached at n = 1280.88still to go0.12κ at n = 8, as a fraction0.17every point is below the line and none of them is on itthe limit is not a value

The condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.95, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 1521 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 87.9% of it at n = 128.

rho: 0.5

The arguments are the ones A preconditioner that changes sign 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.

κ of the ρ = 0.5 Toeplitz family, against the limit it never reachesThe condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.5, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 9 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 99.9% of it at n = 128.10¹10²10¹size ncondition numberlimit 9measureda limit, as a fraction of itselfreached at n = 1281still to go0.0013κ at n = 8, as a fraction0.83every point is below the line and none of them is on itthe limit is not a value

The condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.5, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 9 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 99.9% of it at n = 128.

rho: 0.9

The arguments are the ones A preconditioner that changes sign 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.

κ of the ρ = 0.9 Toeplitz family, against the limit it never reachesThe condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.9, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 361 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 96.0% of it at n = 128.10¹10²10²size ncondition numberlimit 361measureda limit, as a fraction of itselfreached at n = 1280.96still to go0.04κ at n = 8, as a fraction0.31every point is below the line and none of them is on itthe limit is not a value

The condition number of the n×n section of the Kac–Murdock–Szegő matrix ρ^|i−j| at ρ = 0.9, plotted against the size on logarithmic axes, with Szegő's asymptotic value ((1+ρ)/(1−ρ))² = 361 drawn as a horizontal line. The measured curve climbs towards it from below and reaches 96.0% of it at n = 128.

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.

14 distinct claims across 5 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.

and climbs towards it at n = 4 — asserted 6 times

κ at n = 4 is under Szegő's limit — asserted 6 times

a correlation inside the range the limit is finite over

and never arrives

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