[MRG] Cupy backend (#315)

* Cupy backend

* pep8 + bug

* working even if cupy not installed

* attempt to force codecov to ignore cupy because no gpu can be used for testing on github

* docstring

* readme

1 files changed, 18 insertions, 3 deletions

diff --git a/test/test_backend.py b/test/test_backend.py
index 1832b91..2e7eecc 100644
--- a/test/test_backend.py
+++ b/test/test_backend.py
@@ -7,7 +7,7 @@
 
 import ot
 import ot.backend
-from ot.backend import torch, jax
+from ot.backend import torch, jax, cp
 
 import pytest
 
@@ -87,6 +87,20 @@ def test_get_backend():
         with pytest.raises(ValueError):
             get_backend(A, B2)
 
+    if cp:
+        A2 = cp.asarray(A)
+        B2 = cp.asarray(B)
+
+        nx = get_backend(A2)
+        assert nx.__name__ == 'cupy'
+
+        nx = get_backend(A2, B2)
+        assert nx.__name__ == 'cupy'
+
+        # test not unique types in input
+        with pytest.raises(ValueError):
+            get_backend(A, B2)
+
 
 def test_convert_between_backends(nx):
 
@@ -240,7 +254,7 @@ def test_func_backends(nx):
     # Sparse tensors test
     sp_row = np.array([0, 3, 1, 0, 3])
     sp_col = np.array([0, 3, 1, 2, 2])
-    sp_data = np.array([4, 5, 7, 9, 0])
+    sp_data = np.array([4, 5, 7, 9, 0], dtype=np.float64)
 
     lst_tot = []
 
@@ -393,7 +407,8 @@ def test_func_backends(nx):
         lst_b.append(nx.to_numpy(A))
         lst_name.append('argsort')
 
-        A = nx.searchsorted(Mb, Mb, 'right')
+        tmp = nx.sort(Mb)
+        A = nx.searchsorted(tmp, tmp, 'right')
         lst_b.append(nx.to_numpy(A))
         lst_name.append('searchsorted')