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#ifndef _EM_UTILS_H_
#define _EM_UTILS_H_
#include "config.h"
#ifdef HAVE_BOOST_DIGAMMA
#include <boost/math/special_functions/digamma.hpp>
using boost::math::digamma;
#else
#warning Using Mark Johnsons digamma()
#include <cmath>
inline double digamma(double x) {
double result = 0, xx, xx2, xx4;
assert(x > 0);
for ( ; x < 7; ++x)
result -= 1/x;
x -= 1.0/2.0;
xx = 1.0/x;
xx2 = xx*xx;
xx4 = xx2*xx2;
result += log(x)+(1./24.)*xx2-(7.0/960.0)*xx4+(31.0/8064.0)*xx4*xx2-(127.0/30720.0)*xx4*xx4;
return result;
}
#endif
#endif
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