From 0bbd36c0b569e58c3d47177e816b3541fac4b916 Mon Sep 17 00:00:00 2001
From: Rémi Flamary <remi.flamary@gmail.com>
Date: Tue, 21 Mar 2017 09:32:06 +0100
Subject: cleanupt cpp wrapper name

---
 ot/lp/emd_wrap.pyx | 131 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 ot/lp/emd_wrap.pyx

(limited to 'ot/lp/emd_wrap.pyx')

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
+
-- 
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