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#include <pybind11/pybind11.h>
#include <pybind11/numpy.h>
#include <boost/range/iterator_range.hpp>
#include <wasserstein.h>
#include <array>
namespace py = pybind11;
typedef py::array_t<double, py::array::c_style | py::array::forcecast> Dgm;
namespace hera {
template <> struct DiagramTraits<Dgm>{
using PointType = std::array<double,2>;
using RealType = double;
static RealType get_x(const PointType& p) { return std::get<0>(p); }
static RealType get_y(const PointType& p) { return std::get<1>(p); }
};
}
double wasserstein_distance(
Dgm d1, Dgm d2,
double wasserstein_power, double internal_p,
double delta)
{
py::buffer_info buf1 = d1.request();
py::buffer_info buf2 = d2.request();
// shape (n,2) or (0) for empty
if((buf1.ndim!=2 || buf1.shape[1]!=2) && (buf1.ndim!=1 || buf1.shape[0]!=0))
throw std::runtime_error("Diagram 1 must be an array of size n x 2");
if((buf2.ndim!=2 || buf2.shape[1]!=2) && (buf2.ndim!=1 || buf2.shape[0]!=0))
throw std::runtime_error("Diagram 2 must be an array of size n x 2");
typedef hera::DiagramTraits<Dgm>::PointType Point;
auto p1 = (Point*)buf1.ptr;
auto p2 = (Point*)buf2.ptr;
auto diag1 = boost::make_iterator_range(p1, p1+buf1.shape[0]);
auto diag2 = boost::make_iterator_range(p2, p2+buf2.shape[0]);
hera::AuctionParams<double> params;
params.wasserstein_power = wasserstein_power;
// hera encodes infinity as -1...
if(std::isinf(internal_p)) internal_p = hera::get_infinity<double>();
params.internal_p = internal_p;
params.delta = delta;
// The extra parameters are purposedly not exposed for now.
return hera::wasserstein_dist(diag1, diag2, params);
}
PYBIND11_MODULE(hera, m) {
m.def("wasserstein_distance", &wasserstein_distance,
py::arg("X"), py::arg("Y"),
// Should we name those q, p and d instead?
py::arg("wasserstein_power") = 1,
py::arg("internal_p") = std::numeric_limits<double>::infinity(),
py::arg("delta") = .01,
R"pbdoc(
Compute the Wasserstein distance between two diagrams. Points at infinity are supported.
Parameters:
X (n x 2 numpy array): First diagram
Y (n x 2 numpy array): Second diagram
wasserstein_power (float): Wasserstein degree W_q
internal_p (float): Internal Minkowski norm L^p in R^2
delta (float): Relative error 1+delta
Returns:
float: Approximate Wasserstein distance W_q(X,Y)
)pbdoc");
}
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