Added RT as a contributor + "optimized" Cython math operations

Author: rtavenar

README.md

@@ -167,6 +167,7 @@ The contributors to this library are:
 * [Alain Rakotomamonjy](https://sites.google.com/site/alainrakotomamonjy/home)
 * [Vayer Titouan](https://tvayer.github.io/)
 * [Hicham Janati](https://hichamjanati.github.io/) (Unbalanced OT)
+* [Romain Tavenard](https://rtavenar.github.io/) (1d Wasserstein)
 
 This toolbox benefit a lot from open source research and we would like to thank the following persons for providing some code (in various languages):
 

ot/lp/emd_wrap.pyx

@@ -156,11 +156,11 @@ def emd_1d_sorted(np.ndarray[double, ndim=1, mode="c"] u_weights,
     cdef int cur_idx = 0
     while i < n and j < m:
         if metric == 'sqeuclidean':
-            m_ij = (u[i] - v[j]) ** 2
+            m_ij = (u[i] - v[j]) * (u[i] - v[j])
         elif metric == 'cityblock' or metric == 'euclidean':
-            m_ij = abs(u[i] - v[j])
+            m_ij = math.fabs(u[i] - v[j])
         elif metric == 'minkowski':
-            m_ij = math.pow(abs(u[i] - v[j]), p)
+            m_ij = math.pow(math.fabs(u[i] - v[j]), p)
         else:
             m_ij = dist(u[i].reshape((1, 1)), v[j].reshape((1, 1)),
                         metric=metric)[0, 0]