62 lines
1.9 KiB
JavaScript
62 lines
1.9 KiB
JavaScript
/**
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* LogarithmPlotter - 2D plotter software to make BODE plots, sequences and distribution functions.
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* Copyright (C) 2023 Ad5001
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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.pragma library
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.import "../expr-eval.js" as ExprEval
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.import "../utils.js" as Utils
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.import "latex.js" as Latex
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const DERIVATION_PRECISION = 0.1
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var evalVariables = { // Variables not provided by expr-eval.js, needs to be provided manually
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"pi": Math.PI,
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"PI": Math.PI,
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"π": Math.PI,
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"inf": Infinity,
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"infinity": Infinity,
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"Infinity": Infinity,
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"∞": Infinity,
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"e": Math.E,
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"E": Math.E,
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"true": true,
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"false": false
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}
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var currentVars = {}
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var currentObjectsByName = {} // Mirror of currentObjectsByName in objects.js
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const parser = new ExprEval.Parser()
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parser.consts = Object.assign({}, parser.consts, evalVariables)
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// Function definition
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parser.functions.integral = function(a, b, f, variable) {
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// https://en.wikipedia.org/wiki/Simpson%27s_rule
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// Simpler, faster than tokenizing the expression
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f = parser.parse(f).toJSFunction(variable, currentVars)
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return (b-a)/6*(f(a)+4*f((a+b)/2)+f(b))
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}
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parser.functions.derivative = function(f, variable, x) {
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f = parser.parse(f).toJSFunction(variable, currentVars)
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return (f(x+DERIVATION_PRECISION/2)-f(x-DERIVATION_PRECISION/2))/DERIVATION_PRECISION
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}
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