<?php
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/**
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*
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* Function code for the complex atanh() function
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*
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* @copyright Copyright (c) 2013-2018 Mark Baker (https://github.com/MarkBaker/PHPComplex)
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* @license https://opensource.org/licenses/MIT MIT
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*/
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namespace Complex;
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/**
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* Returns the inverse hyperbolic tangent of a complex number.
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*
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* @param Complex|mixed $complex Complex number or a numeric value.
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* @return Complex The inverse hyperbolic tangent of the complex argument.
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* @throws Exception If argument isn't a valid real or complex number.
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*/
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function atanh($complex)
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{
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$complex = Complex::validateComplexArgument($complex);
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if ($complex->isReal()) {
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$real = $complex->getReal();
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if ($real >= -1.0 && $real <= 1.0) {
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return new Complex(\atanh($real));
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} else {
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return new Complex(\atanh(1 / $real), (($real < 0.0) ? M_PI_2 : -1 * M_PI_2));
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}
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}
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$iComplex = clone $complex;
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$iComplex = $iComplex->invertImaginary()
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->reverse();
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return atan($iComplex)
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->invertReal()
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->reverse();
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}
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