commit 69e343f2cc26f7a090fa0a4c4f8cf5064d4df1c9
author vishwakftw <vishwaks@cs.cmu.edu> Fri Nov 15 11:15:02 2019 -0800
committer Facebook Github Bot <facebook-github-bot@users.noreply.github.com> Fri Nov 15 11:16:45 2019 -0800
tree ae7b5923fcaa79b085f723374ee400bf770c5332
parent 23fcc409d533cb8b5b6b2696be976e2eaf875eda

Expose is_signed for dtype (#29511)

Summary:
Changelog:
- Expose is_signed for torch.dtype by modifying torch/csrc/Dtype.cpp
- Allow half, bfloat16 and bool to also been "known" by the isSignedType function
Pull Request resolved: https://github.com/pytorch/pytorch/pull/29511

Test Plan:
- Add tests in test/test_torch.py

Closes https://github.com/pytorch/pytorch/issues/29475

Differential Revision: D18439030

Pulled By: albanD

fbshipit-source-id: 4b1f9da70c1c8dfd0a5bc028b6936acd1c64af47

c10/core/ScalarType.h

diff --git a/c10/core/ScalarType.h b/c10/core/ScalarType.h
index b9be182..4dfffc8 100644
--- a/c10/core/ScalarType.h
+++ b/c10/core/ScalarType.h
@@ -316,11 +316,11 @@
     case ScalarType::name:                       \
       return std::numeric_limits<ctype>::is_signed;
 
-    switch (t) {
-      AT_FORALL_SCALAR_TYPES_AND(Half, CASE_SIGNED)
-      default:
-        AT_ERROR("Unknown ScalarType");
-    }
+  switch (toUnderlying(t)) {
+    AT_FORALL_SCALAR_TYPES_AND3(Half, Bool, BFloat16, CASE_SIGNED)
+    default:
+      AT_ERROR("Unknown ScalarType");
+  }
   #undef CASE_SIGNED
 }
 

test/test_torch.py

diff --git a/test/test_torch.py b/test/test_torch.py
index e5c35a4..716519e 100644
--- a/test/test_torch.py
+++ b/test/test_torch.py
@@ -2427,6 +2427,14 @@
         x = torch.Tensor([1, nan, 2])
         self.assertEqual(torch.isnan(x), torch.ByteTensor([0, 1, 0]))
 
+    def test_dtype_is_signed(self):
+        for dtype in torch.testing.get_all_dtypes():
+            self.assertEqual(dtype.is_signed, torch.is_signed(torch.tensor(0, dtype=dtype)))
+
+        self.assertFalse(torch.quint8.is_signed)
+        self.assertTrue(torch.qint8.is_signed)
+        self.assertTrue(torch.qint32.is_signed)
+
     def test_RNGState(self):
         state = torch.get_rng_state()
         stateCloned = state.clone()

torch/csrc/Dtype.cpp

diff --git a/torch/csrc/Dtype.cpp b/torch/csrc/Dtype.cpp
index c0a0847..a33f783 100644
--- a/torch/csrc/Dtype.cpp
+++ b/torch/csrc/Dtype.cpp
@@ -29,6 +29,15 @@
   }
 }
 
+PyObject *THPDtype_is_signed(THPDtype *self, PyObject *noargs)
+{
+  if (at::isSignedType(self->scalar_type)) {
+    Py_RETURN_TRUE;
+  } else {
+    Py_RETURN_FALSE;
+  }
+}
+
 PyObject *THPDtype_reduce(THPDtype *self, PyObject *noargs)
 {
   /*
@@ -42,6 +51,7 @@
 
 static struct PyGetSetDef THPDtype_properties[] = {
   {"is_floating_point", (getter)THPDtype_is_floating_point, nullptr, nullptr, nullptr},
+  {"is_signed", (getter)THPDtype_is_signed, nullptr, nullptr, nullptr},
   {nullptr}
 };