Merge pull request #25567 from Abdurrahheem:ash/01D-einsum-test

0/1D Einsum Layer Test #25567

This PR introduces 0/1D test cases for Einsum layer.

TODO:
- Add support for 0D tensors to Einsum layer

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/dnn/src/layers/einsum_layer.cpp

@@ -65,12 +65,12 @@ static Mat Transpose(
 
 
 bool IsTransposeRequired(size_t input_rank, const std::vector<size_t>& permutation) {
-    CV_Assert(input_rank == permutation.size());
 
     // No transpose required for scalars
-    if (input_rank == 0){
+    if (input_rank == 0 || permutation.size() == 0){
         return false;
     }
+    CV_Assert(input_rank == permutation.size());
 
     // Weeds out cases where permutation is something like [0, 1, 2] for a 3D input and so on
     bool transpose_required = false;
@@ -616,6 +616,10 @@ void LayerEinsumImpl::preProcessInputs(InputArrayOfArrays& inputs_arr)
         // variable to hold processed version of the original input
         MatShape input_dims = shape(input);
 
+        if (inputSubscriptIndices.empty()){
+            homogenizedInputDims.emplace_back(MatShape(numLetterIndices, 1));
+            continue;
+        }
         const auto& currSubscriptIndices = inputSubscriptIndices[inputIter];
 
         // There should be subscript index (subscript label) for each dim of the input
@@ -870,6 +874,9 @@ void LayerEinsumImpl::processEquation(const std::vector<MatShape>& inputs)
     // Check if number of tokens in equal to number of inputs.
     // For install "ij, jk -> ik" needs to have 2 inputs tensors
     int num_input_tensors = inputs.size();
+    if (lhs_eq_tokens.empty() || (lhs_eq_tokens.size() == 1 && lhs_eq_tokens[0].empty() && lhs_eq == ",") ) {
+        return;
+    }
     CV_CheckEQ(static_cast<int>(lhs_eq_tokens.size()), num_input_tensors,
         "Number of input tensors does not match the number of subscripts in the input equation");
 
@@ -1363,7 +1370,12 @@ Mat LayerEinsumImpl::batchwiseMatMul(
         }
 
         output = Mat(M, N, reshapedInput1.type());
-        fastGemm(false, false, 1.0, reshapedInput1, reshapedInput2, 0.0, output, opt);
+        if (shape(reshapedInput1).empty() && shape(reshapedInput2).empty())
+        {
+            output = reshapedInput1.mul(reshapedInput2); // fastGemm does not support 0D * 0D multiplication
+        } else {
+            fastGemm(false, false, 1.0, reshapedInput1, reshapedInput2, 0.0, output, opt);
+        }
 
         output = output.reshape(1, {1, M, N});
     }

modules/dnn/test/test_layers_1d.cpp

@@ -682,4 +682,79 @@ INSTANTIATE_TEST_CASE_P(/*nothing*/, Layer_Const_Test, testing::Values(
     std::vector<int>({4, 1})
     ));
 
+typedef testing::TestWithParam<tuple<std::vector<int>, std::string>> Layer_Einsum_Test;
+TEST_P(Layer_Einsum_Test, Accuracy_01D)
+{
+    auto tup = GetParam();
+    std::vector<int> input_shape = std::get<0>(tup);
+    std::string equation = std::get<1>(tup);
+
+    LayerParams lp;
+    lp.type = "Einsum";
+    lp.name = "EinsumLayer";
+    lp.set("equation", equation);
+    lp.set("inputSize", 2);
+    lp.set("outputSize", 1);
+    lp.set("inputShapes0", DictValue::arrayInt(&input_shape[0], input_shape.size()));
+    lp.set("inputShapes1", DictValue::arrayInt(&input_shape[0], input_shape.size()));
+
+    Ptr<Layer> layer = EinsumLayer::create(lp);
+
+    cv::Mat input1(input_shape.size(), input_shape.data(), CV_32F);
+    cv::Mat input2(input_shape.size(), input_shape.data(), CV_32F);
+    cv::randn(input1, 0.0, 1.0); cv::randn(input2, 0.0, 1.0);
+
+    std::vector<Mat> inputs = {input1, input2};
+    std::vector<Mat> outputs;
+    runLayer(layer, inputs, outputs);
+    ASSERT_EQ(1, outputs.size());
+
+    // create output_ref to compare with outputs
+    cv::Mat output_ref;
+    int size[] = {1};
+    if (equation == ",->"){
+        output_ref = input1.mul(input2);
+    }else if (equation == "i, i->i"){
+        output_ref = input1.mul(input2);
+    } else if (equation == "i, i->"){
+        output_ref = input1.mul(input2);
+        cv::Scalar sum = cv::sum(output_ref);
+        output_ref = cv::Mat(0, nullptr, CV_32F, sum[0]);
+    } else if (equation == "ij, ij->ij"){
+        output_ref = input1.mul(input2);
+    } else if (equation == "ij, ij->i"){
+        output_ref = input1.mul(input2);
+        if (input_shape[0] == 1){
+            cv::Scalar sum = cv::sum(output_ref);
+            output_ref = cv::Mat(1, size, CV_32F, sum[0]);
+        } else if (input_shape[1] == 1){
+            size[0] = input_shape[0];
+            output_ref = output_ref.reshape(1, 1, size);
+        } else {
+            cv::reduce(output_ref, output_ref, 1, cv::REDUCE_SUM, CV_32F);
+            size[0] = input_shape[0];
+            output_ref = output_ref.reshape(1, 1, size);
+        }
+    } else {
+        output_ref = cv::Mat();
+    }
+
+    ASSERT_EQ(shape(output_ref), shape(outputs[0]));
+    normAssert(output_ref, outputs[0]);
+}
+
+INSTANTIATE_TEST_CASE_P(/*nothing*/, Layer_Einsum_Test, testing::Values(
+    std::make_tuple(std::vector<int>({}), std::string(",->")),
+    std::make_tuple(std::vector<int>({1}), std::string("i, i->i")),
+    std::make_tuple(std::vector<int>({1}), std::string("i, i->")),
+    std::make_tuple(std::vector<int>({4}), std::string("i, i->i")),
+    std::make_tuple(std::vector<int>({4}), std::string("i, i->")),
+    std::make_tuple(std::vector<int>({1, 4}), std::string("ij, ij->ij")),
+    std::make_tuple(std::vector<int>({4, 1}), std::string("ij, ij->ij")),
+    std::make_tuple(std::vector<int>({1, 4}), std::string("ij, ij->i")),
+    std::make_tuple(std::vector<int>({4, 1}), std::string("ij, ij->i")),
+    std::make_tuple(std::vector<int>({4, 4}), std::string("ij, ij->i"))
+    ));
+
+
 }}