| 1 | const CayleyDickson = require('cayley-dickson')
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| 2 | const createScalar = require('./createScalar')
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| 3 | const no = require('not-defined')
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| 4 |
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| 5 | /**
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| 6 | * A composition algebra is one of ℝ, ℂ, ℍ, O:
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| 7 | * Real, Complex, Quaternion, Octonion.
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| 8 | *
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| 9 | * https://en.wikipedia.org/wiki/Composition_algebra
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| 10 | *
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| 11 | * @param {Object} field
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| 12 | * @param {Number} [num] of CayleyDickson construction iterations. Can be 1, 2, 4 or 8.
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| 13 | *
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| 14 | * @returns {Object} Scalar
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| 15 | */
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| 16 |
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| 17 | function CompositionAlgebra (field, num) {
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| 18 | if (no(num)) num = 1
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| 19 |
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| 20 | const logBase2 = [1, 2, 4, 8].indexOf(num)
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| 21 |
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| 22 | if (logBase2 === -1) {
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| 23 | throw new TypeError('Argument n must be 1, 2, 4 or 8')
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| 24 | }
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| 25 |
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| 26 | return createScalar(CayleyDickson(field, logBase2))
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| 27 | }
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| 28 |
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| 29 | module.exports = CompositionAlgebra
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