Generator

update-inherits

One function in the update library, called 4 times across 2 essays. Below: what it draws at its defaults, what it draws at every value an essay asks for, the 13 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 sherman–morrison against a direct solve, on 20×20 systems whose answer is the identity. A is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.1·10⁻¹⁶. The update formula, which is exact algebra, returns 2.5·10⁻⁴ — a slope of 1.00 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.

update-inherits is one function in lib/figures/update.js — rank-one — the correction that is cheaper than the problem, and what it charges. 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.

Sherman–Morrison against a direct solve, on 20×20 systems whose answer is the identityA is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.1·10⁻¹⁶. The update formula, which is exact algebra, returns 2.5·10⁻⁴ — a slope of 1.00 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.10¹10³10⁵10⁷10⁹10¹¹10¹³10¹⁵10⁻¹⁸10⁻¹⁵10⁻¹²10⁻⁹10⁻⁶10⁻³1κ₂(A), the matrix that was updatedrelative forward errorSherman–Morrisondirect solve of A + uvᵀone answer, two routesκ of the answer's matrix1κ of the matrix replaced10·10¹³update formula's error2.5·10⁻⁴direct solve's error1.1·10⁻¹⁶the question's condition number is 1at every point on this axis

A is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.1·10⁻¹⁶. The update formula, which is exact algebra, returns 2.5·10⁻⁴ — a slope of 1.00 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.

n: 20

The arguments are the ones A correction cheaper than the problem 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.

Sherman–Morrison against a direct solve, on 20×20 systems whose answer is the identityA is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.1·10⁻¹⁶. The update formula, which is exact algebra, returns 2.5·10⁻⁴ — a slope of 1.00 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.10¹10³10⁵10⁷10⁹10¹¹10¹³10¹⁵10⁻¹⁸10⁻¹⁵10⁻¹²10⁻⁹10⁻⁶10⁻³1κ₂(A), the matrix that was updatedrelative forward errorSherman–Morrisondirect solve of A + uvᵀone answer, two routesκ of the answer's matrix1κ of the matrix replaced10·10¹³update formula's error2.5·10⁻⁴direct solve's error1.1·10⁻¹⁶the question's condition number is 1at every point on this axis

A is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.1·10⁻¹⁶. The update formula, which is exact algebra, returns 2.5·10⁻⁴ — a slope of 1.00 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.

n: 40

The arguments are the ones A correction cheaper than the problem 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.

Sherman–Morrison against a direct solve, on 40×40 systems whose answer is the identityA is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.9·10⁻¹⁶. The update formula, which is exact algebra, returns 0.0031 — a slope of 1.04 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.10¹10³10⁵10⁷10⁹10¹¹10¹³10¹⁵10⁻¹⁸10⁻¹⁵10⁻¹²10⁻⁹10⁻⁶10⁻³1κ₂(A), the matrix that was updatedrelative forward errorSherman–Morrisondirect solve of A + uvᵀone answer, two routesκ of the answer's matrix1κ of the matrix replaced10·10¹³update formula's error0.0031direct solve's error1.9·10⁻¹⁶the question's condition number is 1at every point on this axis

A is QΛQᵀ with Λ = (1, …, 1, ε) and the rank-one update takes ε back to 1, so A + uvᵀ is the identity and κ of the problem being solved is 1.000000 at every point on the axis. A direct solve returns 1.9·10⁻¹⁶. The update formula, which is exact algebra, returns 0.0031 — a slope of 1.04 against κ(A), the matrix that was replaced. Its arithmetic is three solves against that matrix and there is nowhere else the error could have come from.

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.

13 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 direct solve of it is exact at every ε

a size the repeated orthogonal assemblies can afford

and the update formula is not

LU is for square matrices

matmul shapes agree

the updated matrix is the identity at ε = 0.01

the updated matrix is the identity at ε = 10⁻¹⁰

the updated matrix is the identity at ε = 10⁻¹²

the updated matrix is the identity at ε = 10⁻¹⁴

the updated matrix is the identity at ε = 10⁻⁴

the updated matrix is the identity at ε = 10⁻⁶

the updated matrix is the identity at ε = 10⁻⁸

with a slope of one against the OLD matrix's condition number

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 92 of 198 generators — 77 print a residual and 15 are exempt with a published reason; 106 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.

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