1 |
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2 |
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3 | const deepMap = require('../../utils/collection/deepMap')
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4 |
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5 | function factory (type, config, load, typed) {
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6 | /**
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7 | * Calculate the 10-base logarithm of a value. This is the same as calculating `log(x, 10)`.
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8 | *
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9 | * For matrices, the function is evaluated element wise.
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10 | *
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11 | * Syntax:
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12 | *
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13 | * math.log10(x)
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14 | *
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15 | * Examples:
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16 | *
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17 | * math.log10(0.00001) // returns -5
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18 | * math.log10(10000) // returns 4
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19 | * math.log(10000) / math.log(10) // returns 4
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20 | * math.pow(10, 4) // returns 10000
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21 | *
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22 | * See also:
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23 | *
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24 | * exp, log, log1p, log2
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25 | *
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26 | * @param {number | BigNumber | Complex | Array | Matrix} x
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27 | * Value for which to calculate the logarithm.
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28 | * @return {number | BigNumber | Complex | Array | Matrix}
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29 | * Returns the 10-base logarithm of `x`
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30 | */
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31 | const log10 = typed('log10', {
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32 | 'number': function (x) {
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33 | if (x >= 0 || config.predictable) {
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34 | return _log10(x)
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35 | } else {
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36 | // negative value -> complex value computation
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37 | return new type.Complex(x, 0).log().div(Math.LN10)
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38 | }
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39 | },
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40 |
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41 | 'Complex': function (x) {
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42 | return new type.Complex(x).log().div(Math.LN10)
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43 | },
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44 |
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45 | 'BigNumber': function (x) {
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46 | if (!x.isNegative() || config.predictable) {
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47 | return x.log()
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48 | } else {
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49 | // downgrade to number, return Complex valued result
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50 | return new type.Complex(x.toNumber(), 0).log().div(Math.LN10)
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51 | }
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52 | },
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53 |
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54 | 'Array | Matrix': function (x) {
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55 | return deepMap(x, log10)
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56 | }
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57 | })
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58 |
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59 | log10.toTex = { 1: `\\log_{10}\\left(\${args[0]}\\right)` }
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60 |
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61 | return log10
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62 | }
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63 |
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64 | /**
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65 | * Calculate the 10-base logarithm of a number
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66 | * @param {number} x
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67 | * @return {number}
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68 | * @private
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69 | */
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70 | const _log10 = Math.log10 || function (x) {
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71 | return Math.log(x) / Math.LN10
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72 | }
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73 |
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74 | exports.name = 'log10'
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75 | exports.factory = factory
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