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# -*- coding: utf-8 -*-
"""
Created on Thu Sep 11 08:42:08 2014
@author: rflamary
"""
import numpy as np
cimport numpy as np
cimport cython
cdef extern from "EMD.h":
void EMD_wrap(int n1,int n2, double *X, double *Y,double *D, double *G, double *cost)
@cython.boundscheck(False)
@cython.wraparound(False)
def emd( np.ndarray[double, ndim=1, mode="c"] a,np.ndarray[double, ndim=1, mode="c"] b,np.ndarray[double, ndim=2, mode="c"] M):
"""
Solves the Earth Movers distance problem and returns the optimal transport matrix
:param a: m weights of the source distribution (must sum to one)
:param b: n weights of the target distribution (must sum to one)
:param M: m x n cost matrix
:type a: np.ndarray
:type b: np.ndarray
:type M: np.ndarray
:return: Optimal transport matrix
:rtype: np.ndarray
"""
cdef int n1= M.shape[0]
cdef int n2= M.shape[1]
cdef float cost=0
cdef np.ndarray[double, ndim=2, mode="c"] G=np.zeros([n1, n2])
# calling the function
EMD_wrap(n1,n2,<double*> a.data,<double*> b.data,<double*> M.data,<double*> G.data,<double*> &cost)
return G
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