einsum: don't inplace modify arguments (fixes: #7763) (#7765)

t-vi · ezyang · commit 42a68749bf3e · 2018-05-29T11:26:39.000+01:00
Thank you, Pierce Freeman, for the report and minimal example!
diff --git a/aten/src/ATen/native/Linear.cpp b/aten/src/ATen/native/Linear.cpp
@@ -299,7 +299,7 @@ Tensor einsum(std::string eqn, TensorList tensors) {
     // finally, we insert dimensions for idxes not in the operand 
     for (size_t dim = 0; dim < idx_to_dim.size(); dim++) {
       if (idx_to_dim[dim] == -1) {
-        preprocessed_op.unsqueeze_(dim);
+        preprocessed_op = preprocessed_op.unsqueeze(dim);
       }
     }
     preprocessed_operands.push_back(preprocessed_op);
diff --git a/test/test_torch.py b/test/test_torch.py
@@ -1508,6 +1508,7 @@ def test_einsum(self):
             def do_einsum(*args):
                 return torch.einsum(test[0], args)
             self.assertTrue(torch.autograd.gradcheck(do_einsum, test[1:]))
+            self.assertTrue(A._version == 0)  # check that we do not use inplace ops
 
     def test_sum_all(self):
         def check_sum_all(tensor):

Original file line number	Diff line number	Diff line change
`@@ -299,7 +299,7 @@ Tensor einsum(std::string eqn, TensorList tensors) {`
`299`	`299`	`// finally, we insert dimensions for idxes not in the operand`
`300`	`300`	`for (size_t dim = 0; dim < idx_to_dim.size(); dim++) {`
`301`	`301`	`if (idx_to_dim[dim] == -1) {`
`302`		`- preprocessed_op.unsqueeze_(dim);`
	`302`	`+ preprocessed_op = preprocessed_op.unsqueeze(dim);`
`303`	`303`	`}`
`304`	`304`	`}`
`305`	`305`	`preprocessed_operands.push_back(preprocessed_op);`