Generator

Adding 0.1 to 256, a thousand times, at 8 significand bits

One function in the rounding library, called 8 times across 1 essay. Below: what it draws at its defaults, what it draws at every value an essay asks for, the 5 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 adding 0.1 to 256, a thousand times, at 8 significand bits. Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

stagnation is one function in lib/figures/rounding.js — rounding — the mode, not the precision, that decides the exponent of the error. 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.

Adding 0.1 to 256, a thousand times, at 8 significand bitsThree lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.02505007501000250275300325350375additionsrunning totalround to nearest: nothing arrivesexactstochasticnearesta thousand additionshalf an ulp at 2561moves, round to nearest0moves, stochastic46relative error, nearest0.28relative error, stochastic0.0228 significand bits, unbounded exponenta flat line is not a small error

Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

addend: 0.1

The arguments are the ones A coin flip that fixes the average passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

Adding 0.1 to 256, a thousand times, at 8 significand bitsThree lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.02505007501000250275300325350375additionsrunning totalround to nearest: nothing arrivesexactstochasticnearesta thousand additionshalf an ulp at 2561moves, round to nearest0moves, stochastic46relative error, nearest0.28relative error, stochastic0.0228 significand bits, unbounded exponenta flat line is not a small error

Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

addend: 0.05

The arguments are the ones A coin flip that fixes the average passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

Adding 0.05 to 256, a thousand times, at 8 significand bitsThree lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.02505007501000240260280300320additionsrunning totalround to nearest: nothing arrivesexactstochasticnearesta thousand additionshalf an ulp at 2561moves, round to nearest0moves, stochastic22relative error, nearest0.16relative error, stochastic0.028 significand bits, unbounded exponenta flat line is not a small error

Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

addend: 0.9

The arguments are the ones A coin flip that fixes the average passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

Adding 0.9 to 256, a thousand times, at 8 significand bitsThree lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.0250500750100020040060080010001200additionsrunning totalround to nearest: nothing arrivesexactstochasticnearesta thousand additionshalf an ulp at 2561moves, round to nearest0moves, stochastic257relative error, nearest0.78relative error, stochastic0.118 significand bits, unbounded exponenta flat line is not a small error

Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

addend: 1.1

The arguments are the ones A coin flip that fixes the average passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

Adding 1.1 to 256, a thousand times, at 8 significand bitsThree lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.02505007501000250500750100012501500additionsrunning totalexactstochasticnearesta thousand additionshalf an ulp at 2561moves, round to nearest128moves, stochastic280relative error, nearest0.62relative error, stochastic0.18 significand bits, unbounded exponenta flat line is not a small error

Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

addend: 2

The arguments are the ones A coin flip that fixes the average passes. A value nobody placed would be a picture no essay asked for and no claim was ever checked against.

Adding 2 to 256, a thousand times, at 8 significand bitsThree lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.0250500750100005001000150020002500additionsrunning totalexactstochasticnearesta thousand additionshalf an ulp at 2561moves, round to nearest128moves, stochastic386relative error, nearest0.77relative error, stochastic0.0788 significand bits, unbounded exponenta flat line is not a small error

Three lines against the number of additions: the exact total rising steadily, a staircase following it, and a flat line at the starting value.

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.

5 distinct claims across 6 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 positive addend inside the range drawn

above half an ulp the addend arrives

and stochastic rounding moves it anyway

below half an ulp the total never moves

stochastic rounding is never the worse of the two here

Against the rule

It draws a decomposition and prints its residual. It calls accumulate, 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.

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