///
/// \file
/// This file contains the declaration of the Faddeeva package, which is used
/// only in the Voigtian class in the ComPWA framework.
///

/* Copyright (c) 2012 Massachusetts Institute of Technology
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 * The above copyright notice and this permission notice shall be
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/* Available at: http://ab-initio.mit.edu/Faddeeva

   Header file for Faddeeva.cc; see that file for more information. */

#ifndef FADDEEVA_HH
#define FADDEEVA_HH 1

#include <complex>

namespace Faddeeva {

// compute w(z) = exp(-z^2) erfc(-iz) [ Faddeeva / scaled complex error func ]
extern std::complex<double> w(std::complex<double> z, double relerr = 0);
extern double w_im(double x); // special-case code for Im[w(x)] of real x

// Various functions that we can compute with the help of w(z)

// compute erfcx(z) = exp(z^2) erfc(z)
extern std::complex<double> erfcx(std::complex<double> z, double relerr = 0);
extern double erfcx(double x); // special case for real x

// compute erf(z), the error function of complex arguments
extern std::complex<double> erf(std::complex<double> z, double relerr = 0);
extern double erf(double x); // special case for real x

// compute erfi(z) = -i erf(iz), the imaginary error function
extern std::complex<double> erfi(std::complex<double> z, double relerr = 0);
extern double erfi(double x); // special case for real x

// compute erfc(z) = 1 - erf(z), the complementary error function
extern std::complex<double> erfc(std::complex<double> z, double relerr = 0);
extern double erfc(double x); // special case for real x

// compute Dawson(z) = sqrt(pi)/2  *  exp(-z^2) * erfi(z)
extern std::complex<double> Dawson(std::complex<double> z, double relerr = 0);
extern double Dawson(double x); // special case for real x

} // namespace Faddeeva

#endif // FADDEEVA_HH
