89 lines
1.2 KiB
C++
89 lines
1.2 KiB
C++
//-----------------------------------------------------------------------------
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//
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// Author : philippe.billet@noos.fr
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//
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// erfc(x)
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//
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// GW Added erfc() from Numerical Recipes in C
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//
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//-----------------------------------------------------------------------------
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#include "stdafx.h"
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#include "defs.h"
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static void yyerfc(void);
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void
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eval_erfc(void)
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{
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push(cadr(p1));
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eval();
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yerfc();
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}
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void
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yerfc(void)
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{
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save();
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yyerfc();
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restore();
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}
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static void
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yyerfc(void)
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{
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double d;
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p1 = pop();
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if (isdouble(p1)) {
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d = erfc(p1->u.d);
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push_double(d);
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return;
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}
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push_symbol(ERFC);
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push(p1);
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list(2);
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return;
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}
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// from Numerical Recipes in C
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#ifndef LINUX
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double
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erfc(double x)
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{
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double t, z, ans;
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z = fabs(x);
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t = 1.0 / (1.0 + 0.5 * z);
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ans=t*exp(-z*z-1.26551223+t*(1.00002368+t*(0.37409196+t*(0.09678418+
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t*(-0.18628806+t*(0.27886807+t*(-1.13520398+t*(1.48851587+
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t*(-0.82215223+t*0.17087277)))))))));
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return x >= 0.0 ? ans : 2.0-ans;
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}
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#endif
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static char *s[] = {
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"erfc(a)",
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"erfc(a)",
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"erfc(0.0)",
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"1",
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"float(erfc(0))",
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"1",
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#if 0
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"float(erfc(1))",
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"0.157299",
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#endif
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};
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void
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test_erfc(void)
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{
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test(__FILE__, s, sizeof s / sizeof (char *));
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}
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