15 lines
337 B
Plaintext
15 lines
337 B
Plaintext
"use strict";
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var log = Math.log;
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module.exports = function (value) {
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if (isNaN(value)) return NaN;
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value = Number(value);
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if (value < -1) return NaN;
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if (value > 1) return NaN;
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if (value === -1) return -Infinity;
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if (value === 1) return Infinity;
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if (value === 0) return value;
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return 0.5 * log((1 + value) / (1 - value));
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};
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