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author | Rémi Flamary <remi.flamary@gmail.com> | 2017-03-21 09:32:06 +0100 |
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committer | Rémi Flamary <remi.flamary@gmail.com> | 2017-03-21 09:32:06 +0100 |
commit | 0bbd36c0b569e58c3d47177e816b3541fac4b916 (patch) | |
tree | 2cba51d5447afa3356470371adb216b587832678 /ot/lp/emd_wrap.pyx | |
parent | a84f2c3e23edd1fa89975bd77b08672f518d5ca4 (diff) |
cleanupt cpp wrapper name
Diffstat (limited to 'ot/lp/emd_wrap.pyx')
-rw-r--r-- | ot/lp/emd_wrap.pyx | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/ot/lp/emd_wrap.pyx b/ot/lp/emd_wrap.pyx new file mode 100644 index 0000000..46794ab --- /dev/null +++ b/ot/lp/emd_wrap.pyx @@ -0,0 +1,131 @@ +# -*- 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_c( 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 + + gamm=emd(a,b,M) + + .. math:: + \gamma = arg\min_\gamma <\gamma,M>_F + + s.t. \gamma 1 = a + + \gamma^T 1= b + + \gamma\geq 0 + where : + + - M is the metric cost matrix + - a and b are the sample weights + + Parameters + ---------- + a : (ns,) ndarray, float64 + source histogram + b : (nt,) ndarray, float64 + target histogram + M : (ns,nt) ndarray, float64 + loss matrix + + + Returns + ------- + gamma: (ns x nt) ndarray + Optimal transportation matrix for the given parameters + + """ + 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]) + + if not len(a): + a=np.ones((n1,))/n1 + + if not len(b): + b=np.ones((n2,))/n2 + + # calling the function + EMD_wrap(n1,n2,<double*> a.data,<double*> b.data,<double*> M.data,<double*> G.data,<double*> &cost) + + return G + +@cython.boundscheck(False) +@cython.wraparound(False) +def emd2_c( 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 loss + + gamm=emd(a,b,M) + + .. math:: + \gamma = arg\min_\gamma <\gamma,M>_F + + s.t. \gamma 1 = a + + \gamma^T 1= b + + \gamma\geq 0 + where : + + - M is the metric cost matrix + - a and b are the sample weights + + Parameters + ---------- + a : (ns,) ndarray, float64 + source histogram + b : (nt,) ndarray, float64 + target histogram + M : (ns,nt) ndarray, float64 + loss matrix + + + Returns + ------- + gamma: (ns x nt) ndarray + Optimal transportation matrix for the given parameters + + """ + 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]) + + if not len(a): + a=np.ones((n1,))/n1 + + if not len(b): + b=np.ones((n2,))/n2 + + # calling the function + EMD_wrap(n1,n2,<double*> a.data,<double*> b.data,<double*> M.data,<double*> G.data,<double*> &cost) + + cost=0 + for i in range(n1): + for j in range(n2): + cost+=G[i,j]*M[i,j] + + return cost + |