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Fix bug in tensor contraction. The code assumes that contraction axis indices for the LHS (after possibly swapping to ColMajor!) is increasing. Explicitly sort the contraction axis pairs to make it so.

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This commit is contained in:
Benoit Steiner 2016-03-17 15:08:02 -07:00
parent 46aa9772fc
commit f7329619da
2 changed files with 33 additions and 0 deletions
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13
unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
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@ -193,6 +193,19 @@ struct TensorContractionEvaluatorBase
}
}
// Check for duplicate axes and make sure the first index in eval_op_indices
// is increasing. Using O(n^2) sorting is OK since ContractDims is small
for (int i = 0; i < ContractDims; i++) {
for (int j = i + 1; j < ContractDims; j++) {
eigen_assert(eval_op_indices[j].first != eval_op_indices[i].first &&
eval_op_indices[j].second != eval_op_indices[i].second &&
"contraction axes should be unique");
if (eval_op_indices[j].first < eval_op_indices[i].first) {
numext::swap(eval_op_indices[j], eval_op_indices[i]);
}
}
}
array<Index, LDims> lhs_strides;
lhs_strides[0] = 1;
for (int i = 0; i < LDims-1; ++i) {

20
unsupported/test/cxx11_tensor_contraction.cpp
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@ -138,6 +138,26 @@ static void test_multidims()
mat1(1,0,1)*mat2(1,0,0,1) + mat1(1,1,1)*mat2(1,0,1,1));
VERIFY_IS_APPROX(mat3(1,1,1), mat1(1,0,0)*mat2(1,1,0,0) + mat1(1,1,0)*mat2(1,1,1,0) +
mat1(1,0,1)*mat2(1,1,0,1) + mat1(1,1,1)*mat2(1,1,1,1));
Tensor<float, 2, DataLayout> mat4(2, 2);
Tensor<float, 3, DataLayout> mat5(2, 2, 2);
mat4.setRandom();
mat5.setRandom();
Tensor<float, 1, DataLayout> mat6(2);
mat6.setZero();
Eigen::array<DimPair, 2> dims2({{DimPair(0, 1), DimPair(1, 0)}});
typedef TensorEvaluator<decltype(mat4.contract(mat5, dims2)), DefaultDevice> Evaluator2;
Evaluator2 eval2(mat4.contract(mat5, dims2), DefaultDevice());
eval2.evalTo(mat6.data());
EIGEN_STATIC_ASSERT(Evaluator2::NumDims==1ul, YOU_MADE_A_PROGRAMMING_MISTAKE);
VERIFY_IS_EQUAL(eval2.dimensions()[0], 2);
VERIFY_IS_APPROX(mat6(0), mat4(0,0)*mat5(0,0,0) + mat4(1,0)*mat5(0,1,0) +
mat4(0,1)*mat5(1,0,0) + mat4(1,1)*mat5(1,1,0));
VERIFY_IS_APPROX(mat6(1), mat4(0,0)*mat5(0,0,1) + mat4(1,0)*mat5(0,1,1) +
mat4(0,1)*mat5(1,0,1) + mat4(1,1)*mat5(1,1,1));
}
template<int DataLayout>