From 9e40820bee3570354ffdd35a69e18bd16703719a Mon Sep 17 00:00:00 2001
From: Rémi Flamary <remi.flamary@gmail.com>
Date: Mon, 31 Oct 2016 13:43:48 +0100
Subject: firt DA class

---
 ot/da.py | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 54 insertions(+), 9 deletions(-)

(limited to 'ot/da.py')

diff --git a/ot/da.py b/ot/da.py
index 19d41bc..11e420b 100644
--- a/ot/da.py
+++ b/ot/da.py
@@ -9,7 +9,6 @@ from .lp import emd
 from .utils import unif,dist
 
 
-
 def indices(a, func):
     return [i for (i, val) in enumerate(a) if func(val)]
 
@@ -124,15 +123,20 @@ def sinkhorn_lpl1_mm(a,labels_a, b, M, reg, eta=0.1,numItermax = 10,numInnerIter
 
 
 class OTDA():
-    """Class for optimal transport with domain adaptation"""
+    """Class for domain adaptation with optimal transport"""
     
-    def __init__(self):
+    def __init__(self,metric='sqeuclidean'):
+        """ Class initialization"""
         self.xs=0
         self.xt=0
         self.G=0
+        self.metric=metric
+        self.computed=False
         
     
     def fit(self,xs,xt,ws=None,wt=None):
+        """ Fit domain adaptation between samples is xs and xt (with optional 
+            weights)"""
         self.xs=xs
         self.xt=xt
         
@@ -144,17 +148,58 @@ class OTDA():
         self.ws=ws
         self.wt=wt
             
-        self.M=dist(xs,xt)
+        self.M=dist(xs,xt,metric=self.metric)
         self.G=emd(ws,wt,self.M)
+        self.computed=True
         
     def interp(self,direction=1):
-        """Barycentric interpolation for the source (1) or target (-1)"""
+        """Barycentric interpolation for the source (1) or target (-1)
+        
+        This Barycentric interpolation solves for each source (resp target) 
+        sample xs (resp xt) the following optimization problem:
+        
+        .. math::
+            arg\min_x \sum_i \gamma_{k,i} c(x,x_i^t)
+            
+        where k is the index of the sample in xs
+        
+        For the moment only squared euclidean distance is provided but more 
+        metric c can be used in teh future.            
+        
+        """
+        if direction>0: # >0 then source to target 
+            G=self.G
+            w=self.ws.reshape((self.xs.shape[0],1))
+            x=self.xt
+        else:
+            G=self.G.T
+            w=self.wt.reshape((self.xt.shape[0],1))
+            x=self.xs
+        
+        if self.computed:
+            if self.metric=='sqeuclidean':
+                return np.dot(G/w,x) # weighted mean
+            else:
+                print("Warning, metric not handled yet, using weighted average")
+                return np.dot(G/w,x) # weighted mean              
+                return None                
+        else:
+            print("Warning, model not fitted yet, returning None")
+            return None
+        
         
-        if self.G and direction>0:
-            return (self.G/self.ws).dot(self.xt) 
-        elif self.G and direction<0:
-            return (self.G.T/self.wt).dot(self.xs)
+    def predict(x,direction=1):
+        """ Out of sample mapping using the formulation from Ferradans 
         
+        """
+        if direction>0: # >0 then source to target 
+            G=self.G
+            w=self.ws.reshape((self.xs.shape[0],1))
+            x=self.xt
+        else:
+            G=self.G.T
+            w=self.wt.reshape((self.xt.shape[0],1))
+            x=self.xs        
         
         
         
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