t = evaluate(sum, 2500)
k = evaluate(kahansum, 1500)
f = evaluate(fsum, 500)
evaluate(fsum_1, 3500)
t.s - k.s
t.t / k.t
t.t / f.t
numbers = Float64Array.from({ length: 1e7 }, (_,i ) => Math.random()-.5)
evaluate = async (fun, delay) => {
await Promises.delay(delay);
const t = performance.now();
const s = +fun(numbers);
const v = +fun([14, 1, 2, 3], (d, i) => i === 0 ? -d : d * d); // valueof accessor
return { s, t: performance.now() - t,
v: v ? "🧨" : "👍",
r0: +fun([.3, .3, .3, .3, .3, .3, .3, .3, .3, .3, -.3, -.3, -.3, -.3, -.3, -.3, -.3, -.3, -.3, -.3])
? "🧨" : "👍",
r1: +fun([.1, .1, .1, .1, .1, .1, .1, .1, .1, .1, -1.]) // "🧨" or "👍"? fsum is probably correct
};
}
function kahansum(values, valueof) {
let sum0 = 0,
sum1,
error = 0;
if (valueof === undefined) {
for (let value of values) {
if ((value = +value)) {
sum1 = sum0 + (value -= error);
error = sum1 - sum0 - value;
sum0 = sum1;
}
}
} else {
let index = -1;
for (let value of values) {
if ((value = +valueof(value, ++index, values))) {
sum1 = sum0 + (value -= error);
error = sum1 - sum0 - value;
sum0 = sum1;
}
}
}
return sum0;
}
{
const A = [1, 2, 3];
A.length = 1;
A.push(5);
return A;
}
+fsum_1([.1, .1])
.add([.1, .1, .1, .1])
.add(.1)
.add([-.1, -.1, -.1])
.add(-.1)
.add([-.1, -.1, -.1])
import {fsum} from "727130e216dc8cd4"
// adapted from https://github.com/python/cpython/blob/master/Modules/mathmodule.c#L1444
function fsum_1(iterable, valueof) {
const partials = [];
const isIterable = object =>
object != null && typeof object[Symbol.iterator] === 'function';
const Adder = {
partials,
add: function(t) {
const p = partials;
let n = p.length, i, j, tmp, y, hi, lo, index = -1;
const values = isIterable(t) ? t : [t];
if (valueof) for (let x of values) {
x = valueof(x, ++index, values)
for (i = j = 0; j < n && j < 32; j++) {
if (Math.abs(x) < Math.abs((y = p[j]))) (tmp = x), (x = y), (y = tmp);
hi = x + y;
lo = y - (hi - x);
if (lo) p[i++] = lo;
x = hi;
}
n = i;
p[n++] = x;
}
else for (let x of values) {
for (i = j = 0; j < n && j < 32; j++) {
if (Math.abs(x) < Math.abs((y = p[j]))) (tmp = x), (x = y), (y = tmp);
hi = x + y;
lo = y - (hi - x);
if (lo) p[i++] = lo;
x = hi;
}
n = i;
p[n++] = x;
}
p.splice(n, 32);
return Adder;
},
valueOf: function() {
let n = partials.length,
x,
y,
hi = 0,
lo;
if (n > 0) {
hi = partials[--n];
while (n > 0) {
x = hi;
y = partials[--n];
hi = x + y;
lo = y - (hi - x);
if (lo) break;
}
if (
n > 0 &&
((lo < 0 && partials[n - 1] < 0) || (lo > 0 && partials[n - 1] > 0))
) {
y = lo * 2.0;
x = hi + y;
if (y == x - hi) hi = x;
}
}
return hi;
},
reset: function() {
partials.length = 0;
}
};
if (iterable) Adder.add(iterable);
return Adder;
}
// adapted from https://github.com/python/cpython/blob/master/Modules/mathmodule.c#L1444
function fsum_direct(iterable) {
const p = new Float64Array(32);
let i,
j,
x,
y,
yr,
tmp,
hi,
lo,
n = 0;
for (x of iterable) {
for (i = j = 0; j < n && j < 32; j++) {
if (Math.abs(x) < Math.abs((y = p[j]))) (tmp = x), (x = y), (y = tmp);
hi = x + y;
yr = hi - x;
lo = y - yr;
if (lo) p[i++] = lo;
x = hi;
}
n = i;
p[n++] = x;
}
hi = 0;
if (n > 0) {
hi = p[--n];
while (n > 0) {
x = hi;
y = p[--n];
hi = x + y;
yr = hi - x;
lo = y - yr;
if (lo) break;
}
if (n > 0 && ((lo < 0 && p[n - 1] < 0) || (lo > 0 && p[n - 1] > 0))) {
y = lo * 2.0;
x = hi + y;
yr = x - hi;
if (y == yr) hi = x;
}
}
return hi;
}
function sum(values, valueof) {
let sum = 0;
if (valueof === undefined) {
for (let value of values) {
if ((value = +value)) {
sum += value;
}
}
} else {
let index = -1;
for (let value of values) {
if ((value = +valueof(value, ++index, values))) {
sum += value;
}
}
}
return sum;
}
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