add common infrastructure config files (#1)

.eslintignore

@@ -0,0 +1 @@
+node_modules/**

.eslintrc.json

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+{
+	"extends": "dvpnt"
+}

.gitignore

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+*.tgz
+node_modules/
+.nyc_output/

.npmignore

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+*.tgz
+.eslintignore
+.eslintrc.json
+.gitignore
+.npmignore
+.travis.yml
+test.js
+.nyc_output/

.npmrc

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+save-exact=true
+package-lock=false
+
+@dvpnt:registry=https://registry.npmjs.org

.nvmrc

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+12.13.1

.travis.yml

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+language: node_js
+
+sudo: false
+
+node_js:
+  - 12
+  - stable
+
+script:
+  - npm run lint
+  - npm run test -- --coverage-report=text-lcov --color

LICENSE

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+MIT License
+
+Copyright (c) 2020 dvpnt
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -1 +1,15 @@
-# math
+# @dvpnt/math
+[![Build Status](https://travis-ci.org/dvpnt/math.svg?branch=master)](https://travis-ci.org/dvpnt/math)
+[![Coverage Status](https://coveralls.io/repos/github/dvpnt/math/badge.svg?branch=master)](https://coveralls.io/github/dvpnt/math?branch=master)
+[![NPM Version](https://img.shields.io/npm/v/@dvpnt/math.svg)](https://www.npmjs.com/package/@dvpnt/math)
+
+Mathware of dvpnt
+
+## Installation
+
+    $ npm install @dvpnt/math
+
+
+## License
+
+[The MIT License (MIT)](/LICENSE)

lib/LsmInterpolator/Interpolator.js

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+const _ = require('underscore');
+
+class Interpolator {
+	constructor(coeffs) {
+		this._coeffs = coeffs;
+	}
+
+	of(x) {
+		return _(this._coeffs).reduce((sum, coeff, i) => sum + coeff * x ** i, 0);
+	}
+
+	error(xs, ys) {
+		return _(xs).reduce((error, x, i) => error + Math.abs(this.of(x) - ys[i]), 0);
+	}
+}
+
+module.exports = Interpolator;

lib/LsmInterpolator/index.js

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+const _ = require('underscore');
+const math = require('mathjs');
+const Interpolator = require('./Interpolator');
+
+function createLsmInterpolator({xs, ys, coeffsCount}) {
+	const coeffsRange = _(coeffsCount).isObject() ?
+		_.range(coeffsCount.min, coeffsCount.max + 1) :
+		_.range(coeffsCount, coeffsCount + 1);
+
+	const interpolators = _(coeffsRange)
+		.chain()
+		.map((coeffsCount) => {
+			const line = _.range(0, coeffsCount);
+
+			const lsmMatrix = _(line).map(
+				(i) => _(line).map(
+					(j) => _(xs).reduce((sum, x) => sum + x ** (i + j), 0)
+				)
+			);
+
+			if (Math.abs(math.det(lsmMatrix)) < 1e-5) return;
+
+			const lsmVector = _(line).map(
+				(i) => _(xs).reduce((sum, x, j) => sum + x ** i * ys[j], 0)
+			);
+
+			return new Interpolator(math.lusolve(lsmMatrix, lsmVector));
+		})
+		.compact()
+		.value();
+
+	if (_(interpolators).isEmpty()) {
+		throw new Error('Failed to fit interpolator');
+	}
+
+	return _(interpolators).min((interpolator) => interpolator.error(xs, ys));
+}
+
+module.exports = createLsmInterpolator;

lib/__tests__/LsmInterpolator.js

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+const _ = require('underscore');
+const t = require('tap');
+const {createLsmInterpolator} = require('..');
+
+function interpolate(interpolator, xs) {
+	return _(xs).map((x) => Number(interpolator.of(x).toFixed(3)));
+}
+
+t.test('LsmInterpolator', (t) => {
+	const xs = [0.5, 1, 1.5, 2, 2.5, 3];
+	const ys = [0.35, 0.8, 1.7, 1.85, 3.51, 1.02];
+
+	t.test('with specific coeffs count', (t) => {
+		const interpolator = createLsmInterpolator({xs, ys, coeffsCount: 2});
+
+		t.strictSame(
+			interpolate(interpolator, [0.5, 1.75, 3]),
+			[0.708, 1.538, 2.369],
+			'check interpolation'
+		);
+
+		t.end();
+	});
+
+	t.test('with autofit coeffs count', (t) => {
+		const interpolator =
+			createLsmInterpolator({xs, ys, coeffsCount: {min: 2, max: 10}});
+
+		t.strictSame(
+			interpolate(interpolator, [0.5, 1.75, 3]),
+			[0.35, 1.675, 1.02],
+			'check interpolation'
+		);
+
+		t.end();
+	});
+
+	t.end();
+});

lib/index.js

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+exports.createLsmInterpolator = require('./LsmInterpolator');

package.json

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+{
+  "name": "@dvpnt/math",
+  "version": "0.0.0",
+  "description": "mathematical achievements of dvpnt",
+  "main": "lib/index.js",
+  "scripts": {
+    "lint": "eslint --ext js,jsx --cache ./lib/",
+    "test": "tap lib/**/__tests__/*.js"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/dvpnt/math.git"
+  },
+  "keywords": [
+    "dvpnt",
+    "math"
+  ],
+  "author": "dvpnt",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/dvpnt/math/issues"
+  },
+  "homepage": "https://github.com/dvpnt/math#readme",
+  "dependencies": {
+    "mathjs": "6.5.0",
+    "nrun": "1.0.0",
+    "underscore": "1.9.1"
+  },
+  "devDependencies": {
+    "eslint": "6.8.0",
+    "eslint-config-dvpnt": "4.0.8",
+    "eslint-plugin-import": "2.22.0",
+    "tap": "14.6.1"
+  }
+}