Ratio.quantize() shouldn't increase precision unnecessarily #9926
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The potential loss of precision is persuasive. E.g. quantizing 1/3 by 10.
Please update the no longer correct jsdoc:
Make an equivalant ratio with a new denominator
(had a typo too)
In the next push, please squash all commits into one. The test change is necessary for the feat commit alone to pass CI.
| @@ -352,6 +352,10 @@ export const ratiosSame = (left, right) => { | |||
| export const quantize = (ratio, newDen) => { | |||
| const oldDen = ratio.denominator.value; | |||
| const oldNum = ratio.numerator.value; | |||
| if (oldDen < newDen) { | |||
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ignorable nit: testing the param against the status quo reads more conventionally to me
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| if (oldDen < newDen) { | |
| if (newDen > oldDen) { |
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very correct.
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Description
Ratios are designed to hold fractions as ratios with arbitrary length denominators. A few operations (multiplication) can cause the denominators to grow rapidly. To allow holders of growing ratios to manage this, we provide a method
quantize(), which returns a ratio that approximates the original value, but with a smaller denominator.The current implementation uses the provided denominator even if it is larger. This doesn't gain anything, and can lose precision unnecessarily
Security Considerations
No security implications.
Scaling Considerations
The quantize() method is used to limit the size of very large BigInts. This improvement only makes that better.
Documentation Considerations
No need for changes. The current doc does say "Make an equivalant ratio with a new denominator", even though the result is only an approximation.
Testing Considerations
Added new tests.
Upgrade Considerations
No hurry to get this included in any particular contract upgrade.