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Own sqrt

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This commit is contained in:
Jaco Greeff 2020-03-23 21:06:18 +01:00
parent 2957aa572d
commit 3ba4d5bdbf
1 changed files with 28 additions and 5 deletions
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33
packages/page-democracy/src/Overview/useIsPassing.ts
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@ -3,7 +3,7 @@
// of the Apache-2.0 license. See the LICENSE file for details.
import { DerivedReferendum } from '@polkadot/api-derive/types';
import { ReferendumStatus } from '@polkadot/types/interfaces';
import { Balance, ReferendumStatus } from '@polkadot/types/interfaces';
import BN from 'bn.js';
import { useState, useEffect } from 'react';
@ -36,9 +36,32 @@ function compareRationals (n1: BN, d1: BN, n2: BN, d2: BN): boolean {
}
}
function newtonIteration (n: BN, x0: BN): BN {
const x1 = n.div(x0).add(x0).shrn(1);
if (x0.eq(x1) || x0.eq(x1.subn(1))) {
return x0;
}
return newtonIteration(n, x1);
}
// https://golb.hplar.ch/2018/09/javascript-bigint.html
function sqrt (value: BN): BN {
if (value.ltn(0)) {
throw new Error('square root of negative numbers is not supported');
}
if (value.ltn(2)) {
return value;
}
return newtonIteration(value, new BN(1));
}
export default function useIsPassing (referendum: DerivedReferendum): boolean | undefined {
const { api } = useApi();
const totalIssuance = useCall<BN>(api.query.balances.totalIssuance, []);
const totalIssuance = useCall<Balance>(api.query.balances.totalIssuance, []);
const [isPassing, setIsPassing] = useState<boolean | undefined>(undefined);
useEffect((): void => {
@ -46,9 +69,9 @@ export default function useIsPassing (referendum: DerivedReferendum): boolean |
// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
const { tally, threshold } = (referendum.status as ReferendumStatus);
if (totalIssuance?.gtn(0) && tally?.turnout.gtn(0)) {
const sqrtVoters = tally.turnout.toRed(BN.red('k256')).redSqrt().fromRed();
const sqrtElectorate = totalIssuance.toRed(BN.red('k256')).redSqrt().fromRed();
if (totalIssuance && tally) {
const sqrtVoters = sqrt(tally.turnout);
const sqrtElectorate = sqrt(totalIssuance);
setIsPassing(
sqrtVoters.isZero()