1 | import { factory } from '../../utils/factory.js';
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2 | import { deepMap } from '../../utils/collection.js';
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3 | import { log1p as _log1p } from '../../utils/number.js';
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4 | var name = 'log1p';
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5 | var dependencies = ['typed', 'config', 'divideScalar', 'log', 'Complex'];
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6 | export var createLog1p = /* #__PURE__ */factory(name, dependencies, (_ref) => {
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7 | var {
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8 | typed,
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9 | config,
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10 | divideScalar,
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11 | log,
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12 | Complex
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13 | } = _ref;
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14 |
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15 | /**
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16 | * Calculate the logarithm of a `value+1`.
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17 | *
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18 | * For matrices, the function is evaluated element wise.
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19 | *
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20 | * Syntax:
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21 | *
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22 | * math.log1p(x)
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23 | * math.log1p(x, base)
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24 | *
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25 | * Examples:
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26 | *
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27 | * math.log1p(2.5) // returns 1.252762968495368
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28 | * math.exp(math.log1p(1.4)) // returns 2.4
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29 | *
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30 | * math.pow(10, 4) // returns 10000
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31 | * math.log1p(9999, 10) // returns 4
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32 | * math.log1p(9999) / math.log(10) // returns 4
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33 | *
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34 | * See also:
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35 | *
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36 | * exp, log, log2, log10
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37 | *
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38 | * @param {number | BigNumber | Complex | Array | Matrix} x
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39 | * Value for which to calculate the logarithm of `x+1`.
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40 | * @param {number | BigNumber | Complex} [base=e]
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41 | * Optional base for the logarithm. If not provided, the natural
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42 | * logarithm of `x+1` is calculated.
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43 | * @return {number | BigNumber | Complex | Array | Matrix}
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44 | * Returns the logarithm of `x+1`
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45 | */
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46 | return typed(name, {
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47 | number: function number(x) {
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48 | if (x >= -1 || config.predictable) {
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49 | return _log1p(x);
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50 | } else {
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51 | // negative value -> complex value computation
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52 | return _log1pComplex(new Complex(x, 0));
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53 | }
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54 | },
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55 | Complex: _log1pComplex,
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56 | BigNumber: function BigNumber(x) {
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57 | var y = x.plus(1);
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58 |
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59 | if (!y.isNegative() || config.predictable) {
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60 | return y.ln();
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61 | } else {
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62 | // downgrade to number, return Complex valued result
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63 | return _log1pComplex(new Complex(x.toNumber(), 0));
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64 | }
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65 | },
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66 | 'Array | Matrix': function ArrayMatrix(x) {
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67 | return deepMap(x, this);
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68 | },
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69 | 'any, any': function anyAny(x, base) {
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70 | // calculate logarithm for a specified base, log1p(x, base)
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71 | return divideScalar(this(x), log(base));
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72 | }
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73 | });
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74 | /**
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75 | * Calculate the natural logarithm of a complex number + 1
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76 | * @param {Complex} x
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77 | * @returns {Complex}
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78 | * @private
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79 | */
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80 |
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81 | function _log1pComplex(x) {
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82 | var xRe1p = x.re + 1;
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83 | return new Complex(Math.log(Math.sqrt(xRe1p * xRe1p + x.im * x.im)), Math.atan2(x.im, xRe1p));
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84 | }
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85 | }); |
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