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erfQ.cc
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// -*- C++ -*-
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//
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// -----------------------------------------------------------------------
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// HEP Random
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// --- erfQ ---
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// method implementation file
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// -----------------------------------------------------------------------
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// Contains methods that do not depend on large tables.
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//
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// erfQ (double x)
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// =======================================================================
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// M Fischler - Created 1/26/00.
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//
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// =======================================================================
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#include "
CLHEP/Random/Stat.h
"
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#include <cmath>
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namespace
CLHEP {
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double
HepStat::erfQ
(
double
x
) {
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//
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// erfQ is accurate to 7 places.
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// See Numerical Recipes P 221
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//
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double
t
,
z
, erfc;
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z =
std::abs
(x);
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t = 1.0/(1.0+.5*
z
);
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erfc= t*std::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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// (The derivation of this formula should be obvious.)
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if
( x < 0 ) erfc = 2.0 - erfc;
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return
1 - erfc;
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}
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}
// namespace CLHEP
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geant4-10.6-release
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erfQ.cc
Built by
Jin Huang
. updated:
Wed Jun 29 2022 17:25:14
using
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