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25 lines
372 B
C
25 lines
372 B
C
/* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */
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#include <math.h>
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#ifdef _MSC_VER
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#pragma function(tanh)
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#endif
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/*
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* @implemented
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*/
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double tanh(double x)
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{
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if (x > 50)
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return 1;
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else if (x < -50)
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return -1;
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else
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{
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const double ebig = exp(x);
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const double esmall = 1.0/ebig;
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return (ebig - esmall) / (ebig + esmall);
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}
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}
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