sketches-js-hassy
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TypeScript implementation of DDSketch, a distributed quantile sketch algorithm
52 lines (51 loc) • 2.3 kB
JavaScript
;
/*
* Unless explicitly stated otherwise all files in this repository are licensed
* under the Apache 2.0 license (see LICENSE).
* This product includes software developed at Datadog (https://www.datadoghq.com/).
* Copyright 2020 Datadog, Inc.
*/
var __extends = (this && this.__extends) || (function () {
var extendStatics = function (d, b) {
extendStatics = Object.setPrototypeOf ||
({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
return extendStatics(d, b);
};
return function (d, b) {
if (typeof b !== "function" && b !== null)
throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
extendStatics(d, b);
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
exports.LogarithmicMapping = void 0;
var KeyMapping_1 = require("./KeyMapping");
var compiled_1 = require("../proto/compiled");
/**
* A memory-optimal KeyMapping, i.e., given a targeted relative accuracy, it
* requires the least number of keys to cover a given range of values. This is
* done by logarithmically mapping floating-point values to integers.
*/
var LogarithmicMapping = /** @class */ (function (_super) {
__extends(LogarithmicMapping, _super);
function LogarithmicMapping(relativeAccuracy, offset) {
if (offset === void 0) { offset = 0; }
var _this = _super.call(this, relativeAccuracy, offset) || this;
_this._multiplier *= Math.log(2);
return _this;
}
LogarithmicMapping.prototype._logGamma = function (value) {
return Math.log2(value) * this._multiplier;
};
LogarithmicMapping.prototype._powGamma = function (value) {
return Math.pow(2, value / this._multiplier);
};
LogarithmicMapping.prototype._protoInterpolation = function () {
return compiled_1.IndexMapping.Interpolation.NONE;
};
return LogarithmicMapping;
}(KeyMapping_1.KeyMapping));
exports.LogarithmicMapping = LogarithmicMapping;