feat(//py): Allow example tensors from torch to set shape

Signed-off-by: Naren Dasan <naren@narendasan.com>
Signed-off-by: Naren Dasan <narens@nvidia.com>

py/trtorch/Input.py

@@ -196,3 +196,10 @@ def _parse_format(format: Any) -> _types.TensorFormat:
         else:
             raise TypeError(
                 "Tensor format needs to be specified with either torch.memory_format or trtorch.TensorFormat")
+
+    @classmethod
+    def _from_tensor(cls, t: torch.Tensor):
+        if not any([t.is_contiguous(memory_format=torch.contiguous_format), t.is_contiguous(memory_format=torch.channels_last)]):
+            raise ValueError("Tensor does not have a supported contiguous memory format, supported formats are contiguous or channel_last")
+        frmt = torch.contiguous_format if t.is_contiguous(memory_format=torch.contiguous_format) else torch.channels_last
+        return cls(shape=t.shape, dtype=t.dtype, format=frmt)

py/trtorch/_compile_spec.py

@@ -174,7 +174,11 @@ def _parse_compile_spec(compile_spec: Dict[str, Any]) -> trtorch._C.CompileSpec:
         info.inputs = _parse_input_ranges(compile_spec["input_shapes"])
 
     if "inputs" in compile_spec:
-        info.inputs = [i._to_internal() for i in compile_spec["inputs"]]
+        if not all([isinstance(i, torch.Tensor) or isinstance(i, trtorch.Input) for i in compile_spec["inputs"]]):
+            raise KeyError("Input specs should be either trtorch.Input or torch.Tensor, found types: {}".format([typeof(i) for i in compile_spec["inputs"]]))
+
+        inputs = [trtorch.Input._from_tensor(i) if isinstance(i, torch.Tensor) else i for i in compile_spec["inputs"]]
+        info.inputs = [i._to_internal() for i in inputs]
 
     if "op_precision" in compile_spec and "enabled_precisions" in compile_spec:
         raise KeyError(

tests/py/test_api.py

@@ -73,6 +73,30 @@ def test_compile_script(self):
         same = (trt_mod(self.input) - self.scripted_model(self.input)).abs().max()
         self.assertTrue(same < 2e-2)
 
+    def test_from_torch_tensor(self):
+        compile_spec = {
+            "inputs": [self.input],
+            "device": {
+                "device_type": trtorch.DeviceType.GPU,
+                "gpu_id": 0,
+            },
+            "enabled_precisions": {torch.float}
+        }
+
+        trt_mod = trtorch.compile(self.scripted_model, compile_spec)
+        same = (trt_mod(self.input) - self.scripted_model(self.input)).abs().max()
+        self.assertTrue(same < 2e-2)
+
+    def test_device(self):
+        compile_spec = {
+            "inputs": [self.input],
+            "device": trtorch.Device("gpu:0"),
+            "enabled_precisions": {torch.float}
+        }
+
+        trt_mod = trtorch.compile(self.scripted_model, compile_spec)
+        same = (trt_mod(self.input) - self.scripted_model(self.input)).abs().max()
+        self.assertTrue(same < 2e-2)
 
 class TestCompileHalf(ModelTestCase):