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86d333ee94
* chore: Switch to Node 20 + Vitest * chore: migrate to vitest mock functions * chore: code style (switch to prettier) * test: re-enable long-running test Seems the switch to Node 20 and Vitest has vastly improved the code's and / or the test's runtime! see #1193 * chore: code style * chore: fix failing tests * Updated Documentation in README.md * Update contribution guidelines to state usage of Prettier * fix: set prettier printWidth back to 80 * chore: apply updated code style automatically * fix: set prettier line endings to lf again * chore: apply updated code style automatically --------- Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> Co-authored-by: Lars Müller <34514239+appgurueu@users.noreply.github.com>
29 lines
1.3 KiB
JavaScript
29 lines
1.3 KiB
JavaScript
/**
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* @function agm
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* @description This finds the Arithmetic-Geometric Mean between any 2 numbers.
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* @param {Number} a - 1st number, also used to store Arithmetic Mean.
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* @param {Number} g - 2nd number, also used to store Geometric Mean.
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* @return {Number} - AGM of both numbers.
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* @see [AGM](https://en.wikipedia.org/wiki/Arithmetic%E2%80%93geometric_mean)
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*/
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export const agm = (a, g) => {
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if (a === Infinity && g === 0) return NaN
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if (Object.is(a, -0) && !Object.is(g, -0)) return 0
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if (a === g) return a // avoid rounding errors, and increase efficiency
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let x // temp var
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do {
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;[a, g, x] = [(a + g) / 2, Math.sqrt(a * g), a]
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} while (a !== x && !isNaN(a))
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/*
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`x !== a` ensures the return value has full precision,
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and prevents infinite loops caused by rounding differences between `div` and `sqrt` (no need for "epsilon").
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If we were to compare `a` with `g`, some input combinations (not all) can cause an infinite loop,
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because the rounding mode never changes at runtime.
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Precision is not the same as accuracy, but they're related.
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This function isn't always 100% accurate (round-errors), but at least is more than 95% accurate.
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`!isNaN(x)` prevents infinite loops caused by invalid inputs like: negatives, NaNs and Infinities.
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*/
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return a
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}
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