Function binom

python/include/unsupported/test/matrix_exponential.cpp:12–18

#include "matrix_functions.h"

double binom(int n, int k)
{
  double res = 1;
  for (int i=0; i<k; i++)
    res = res * (n-k+i+1) / (i+1);
  return res;
}

template <typename T>
T expfn(T x, int)