Add test for #17271 (torch.exp incorrect for 2**31 size tensor) (#18292)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18292
ghimport-source-id: a3e96584db0eef7b6202a1211808f9f6e59dd529

Stack from [ghstack](https://github.com/ezyang/ghstack):
* **#18292 Add test for #17271 (torch.exp incorrect for 2**31 size tensor)**
* #18291 Correctly call superclass setUp in TestCase subclasses.

Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Differential Revision: D14567642

fbshipit-source-id: c60ee7597a86f5d2c5c0b72cb106f17815950427

diff --git a/test/test_torch.py b/test/test_torch.py
index 20563a6..5cc1ee8 100644 (file)
--- a/test/test_torch.py
+++ b/test/test_torch.py
@@ -766,6 +766,15 @@ class _TestTorchMixin(object):
                 return inf
         self._test_math(torch.exp, exp)
 
+    @slowTest
+    def test_exp_slow(self):
+        # Test for https://github.com/pytorch/pytorch/issues/17271
+        # This is pretty slow on my Macbook but it only takes a few
+        # seconds on a beefy Xeon server
+        a = torch.exp(torch.ones(2 ** 31, dtype=torch.float32))
+        b = torch.exp(torch.ones(1, dtype=torch.float32))
+        self.assertEqual(a, b.expand(2 ** 31))
+
     def test_expm1(self):
         def expm1(x):
             try: