Merge pull request #127 from Quansight-Labs/fix-stuff

Add register_backend docs and fix a bunch of bugs.

uarray/backend.py

@@ -383,12 +383,12 @@ def try_backend(self, method: MultiMethod, args: Tuple, kwargs: Dict, coerce: bo
 
 def _backend_order() -> Iterable[BackendCoerceType]:
     only = _only_backend.get()
+    skip = _skipped_backend.get()
 
-    if only is not None:
+    if only is not None and only not in skip:
         return (only,)
 
     pref = _preferred_backend.get()
-    skip = _skipped_backend.get()
 
     return filter(lambda x: x[0] not in skip, itertools.chain(pref, itertools.product(_backends, (False,))))
 
@@ -493,6 +493,16 @@ def inner(method, args, kwargs, dispatchable_args):
 
 
 def register_backend(backend: Backend):
+    """
+    This utility method registers the backend for permanent use. It
+    will be tried in the list of backends automatically, unless the
+    ``only`` flag is set on a backend.
+
+    Parameters
+    ----------
+    backend : Backend
+        The backend to register.
+    """
     _backends.add(backend)
 
 

unumpy/torch_backend.py

@@ -76,7 +76,7 @@ def reduce(self, a, axis=0, dtype=None, out=None, keepdims=False):
 @register_torch(multimethods.asarray)
 def asarray(a, dtype=None, order=None):
     if torch.is_tensor(a):
-        if a.dtype != dtype:
+        if dtype is None or a.dtype != dtype:
             ret = torch.tensor(a, dtype=dtype)
             if a.requires_grad:
                 ret.requires_grad_()