[MRG] Add factored coupling (#358)

* add gfactored ot

* pep8 and add doc

* add exmaple for factotred OT

* final number of PR

* correct test on backends

* remove useless loss

* better tests

1 files changed, 6 insertions, 1 deletions

diff --git a/ot/plot.py b/ot/plot.py
index 2208c90..8ade2eb 100644
--- a/ot/plot.py
+++ b/ot/plot.py
@@ -85,8 +85,13 @@ def plot2D_samples_mat(xs, xt, G, thr=1e-8, **kwargs):
     if ('color' not in kwargs) and ('c' not in kwargs):
         kwargs['color'] = 'k'
     mx = G.max()
+    if 'alpha' in kwargs:
+        scale = kwargs['alpha']
+        del kwargs['alpha']
+    else:
+        scale = 1
     for i in range(xs.shape[0]):
         for j in range(xt.shape[0]):
             if G[i, j] / mx > thr:
                 pl.plot([xs[i, 0], xt[j, 0]], [xs[i, 1], xt[j, 1]],
-                        alpha=G[i, j] / mx, **kwargs)
+                        alpha=G[i, j] / mx * scale, **kwargs)