50 lines
1.4 KiB
JavaScript
50 lines
1.4 KiB
JavaScript
// SERVER-5044 Standard deviation expression operators
|
|
|
|
const t = db[jsTestName()];
|
|
|
|
function test(data, popExpected, sampExpected) {
|
|
t.drop();
|
|
assert.commandWorked(t.insert({})); // need one document to ensure we get output
|
|
|
|
for (let i = 0; i < data.length; i++) assert.commandWorked(t.insert({num: data[i]}));
|
|
|
|
let res = t
|
|
.aggregate({
|
|
$group: {
|
|
_id: 1,
|
|
pop: {$stdDevPop: "$num"},
|
|
samp: {$stdDevSamp: "$num"},
|
|
},
|
|
})
|
|
.next();
|
|
|
|
if (popExpected === null) {
|
|
assert.isnull(res.pop);
|
|
} else {
|
|
assert.close(res.pop, popExpected, "", 10 /*decimal places*/);
|
|
}
|
|
|
|
if (sampExpected === null) {
|
|
assert.isnull(res.samp);
|
|
} else {
|
|
assert.close(res.samp, sampExpected, "", 10 /*decimal places*/);
|
|
}
|
|
}
|
|
|
|
test([], null, null);
|
|
test([1], 0, null);
|
|
test([1, 1], 0, 0);
|
|
|
|
test(["a"], null, null);
|
|
test([1, "a"], 0, null);
|
|
test([1, "a", 1], 0, 0);
|
|
|
|
test([1, 2], 0.5, Math.sqrt(0.5));
|
|
test([1, 2, 3], Math.sqrt(2 / 3), 1);
|
|
|
|
// test from http://en.wikipedia.org/wiki/Algorithms_for_calculating_variance#Example
|
|
test([4, 7, 13, 16], Math.sqrt(22.5), Math.sqrt(30));
|
|
test([1e8 + 4, 1e8 + 7, 1e8 + 13, 1e8 + 16], Math.sqrt(22.5), Math.sqrt(30));
|
|
test([1e9 + 4, 1e9 + 7, 1e9 + 13, 1e9 + 16], Math.sqrt(22.5), Math.sqrt(30));
|
|
test([1e10 + 4, 1e10 + 7, 1e10 + 13, 1e10 + 16], Math.sqrt(22.5), Math.sqrt(30));
|