Add skeleton for CLScatter op, reference and tests

- Adds dataset for tests
- Adds skeleton for function, operator, reference and tests

Resolves: [COMPMID-6889]
Signed-off-by: Mohammed Suhail Munshi <MohammedSuhail.Munshi@arm.com>
Change-Id: I7e57e8b4577fef6aa7421e672894c249cad6c5fa
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/11234
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gunes Bayir <gunes.bayir@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3f22235..20a010f 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2023 Arm Limited.
+# Copyright (c) 2023-2024 Arm Limited.
 #
 # SPDX-License-Identifier: MIT
 #
@@ -100,6 +100,7 @@
           validation/reference/Floor.cpp
           validation/reference/PriorBoxLayer.cpp
           validation/reference/Scale.cpp
+          validation/reference/ScatterLayer.cpp
           validation/reference/ReorgLayer.cpp
           validation/reference/Range.cpp
           validation/reference/ArithmeticDivision.cpp
diff --git a/tests/datasets/ScatterDataset.h b/tests/datasets/ScatterDataset.h
new file mode 100644
index 0000000..09f6338
--- /dev/null
+++ b/tests/datasets/ScatterDataset.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2024 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef ACL_TESTS_DATASETS_SCATTERDATASET_H
+#define ACL_TESTS_DATASETS_SCATTERDATASET_H
+
+#include "arm_compute/core/TensorShape.h"
+#include "utils/TypePrinter.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace datasets
+{
+
+class ScatterDataset
+{
+public:
+    using type = std::tuple<TensorShape, TensorShape, TensorShape, TensorShape>;
+
+    struct iterator
+    {
+        iterator(std::vector<TensorShape>::const_iterator src_it,
+                 std::vector<TensorShape>::const_iterator updates_it,
+                 std::vector<TensorShape>::const_iterator indices_it,
+                 std::vector<TensorShape>::const_iterator dst_it)
+            : _src_it{ std::move(src_it) },
+              _updates_it{ std::move(updates_it) },
+              _indices_it{std::move(indices_it)},
+              _dst_it{ std::move(dst_it) }
+        {
+        }
+
+        std::string description() const
+        {
+            std::stringstream description;
+            description << "A=" << *_src_it << ":";
+            description << "B=" << *_updates_it << ":";
+            description << "C=" << *_indices_it << ":";
+            description << "Out=" << *_dst_it << ":";
+            return description.str();
+        }
+
+        ScatterDataset::type operator*() const
+        {
+            return std::make_tuple(*_src_it, *_updates_it, *_indices_it, *_dst_it);
+        }
+
+        iterator &operator++()
+        {
+            ++_src_it;
+            ++_updates_it;
+            ++_indices_it;
+            ++_dst_it;
+
+            return *this;
+        }
+
+    private:
+        std::vector<TensorShape>::const_iterator _src_it;
+        std::vector<TensorShape>::const_iterator _updates_it;
+        std::vector<TensorShape>::const_iterator _indices_it;
+        std::vector<TensorShape>::const_iterator _dst_it;
+    };
+
+    iterator begin() const
+    {
+        return iterator(_src_shapes.begin(), _update_shapes.begin(), _indices_shapes.begin(), _dst_shapes.begin());
+    }
+
+    int size() const
+    {
+        return std::min(_src_shapes.size(), std::min(_indices_shapes.size(), std::min(_update_shapes.size(), _dst_shapes.size())));
+    }
+
+    void add_config(TensorShape a, TensorShape b, TensorShape c, TensorShape dst)
+    {
+        _src_shapes.emplace_back(std::move(a));
+        _update_shapes.emplace_back(std::move(b));
+        _indices_shapes.emplace_back(std::move(c));
+        _dst_shapes.emplace_back(std::move(dst));
+    }
+
+protected:
+    ScatterDataset()                 = default;
+    ScatterDataset(ScatterDataset &&) = default;
+
+private:
+    std::vector<TensorShape> _src_shapes{};
+    std::vector<TensorShape> _update_shapes{};
+    std::vector<TensorShape> _indices_shapes{};
+    std::vector<TensorShape> _dst_shapes{};
+};
+
+class SmallScatterDataset final : public ScatterDataset
+{
+public:
+    SmallScatterDataset()
+    {
+        add_config(TensorShape(6U), TensorShape(6U), TensorShape(6U), TensorShape(6U));
+    }
+};
+} // namespace datasets
+} // namespace test
+} // namespace arm_compute
+#endif // ACL_TESTS_DATASETS_SCATTERDATASET_H
diff --git a/tests/validation/CL/ScatterLayer.cpp b/tests/validation/CL/ScatterLayer.cpp
new file mode 100644
index 0000000..040ca41
--- /dev/null
+++ b/tests/validation/CL/ScatterLayer.cpp
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2024 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "arm_compute/runtime/CL/CLTensor.h"
+#include "arm_compute/runtime/CL/functions/CLScatter.h"
+#include "tests/validation/fixtures/ScatterLayerFixture.h"
+#include "tests/CL/CLAccessor.h"
+#include "tests/framework/Macros.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace
+{
+constexpr AbsoluteTolerance<float>   tolerance_f32(0.001f);  /**< Tolerance value for comparing reference's output against implementation's output for 32-bit floating-point type */
+constexpr AbsoluteTolerance<float>   tolerance_f16(0.01f);   /**< Tolerance value for comparing reference's output against implementation's output for 16-bit floating-point type */
+constexpr AbsoluteTolerance<uint8_t> tolerance_qasymm8(1);   /**< Tolerance value for comparing reference's output against implementation's output for 8-bit asymmetric type */
+constexpr AbsoluteTolerance<int8_t>  tolerance_qasymm8_s(1); /**< Tolerance value for comparing reference's output against implementation's output for 8-bit signed asymmetric type */
+} // namespace
+
+template <typename T>
+using CLScatterLayerFixture = ScatterValidationFixture<CLTensor, CLAccessor, CLScatter, T>;
+
+TEST_SUITE(CL)
+TEST_SUITE(ScatterLayer)
+TEST_SUITE(Float)
+TEST_SUITE(FP32)
+TEST_SUITE_END() // FP32
+TEST_SUITE_END() // Float
+TEST_SUITE_END() // ScatterLayer
+TEST_SUITE_END() // CL
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/fixtures/ScatterLayerFixture.h b/tests/validation/fixtures/ScatterLayerFixture.h
new file mode 100644
index 0000000..750e272
--- /dev/null
+++ b/tests/validation/fixtures/ScatterLayerFixture.h
@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2024 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef ACL_TESTS_VALIDATION_FIXTURES_SCATTERLAYERFIXTURE_H
+#define ACL_TESTS_VALIDATION_FIXTURES_SCATTERLAYERFIXTURE_H
+
+#include "arm_compute/core/Utils.h"
+#include "tests/Globals.h"
+#include "tests/framework/Asserts.h" // Required for ARM_COMPUTE_ASSERT
+#include "tests/framework/Fixture.h"
+#include "tests/validation/Validation.h"
+#include "tests/validation/reference/ScatterLayer.h"
+#include "tests/SimpleTensor.h"
+#include <random>
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+template <typename TensorType, typename AccessorType, typename FunctionType, typename T>
+class ScatterGenericValidationFixture : public framework::Fixture
+{
+public:
+    void setup(TensorShape src_shape, TensorShape updates_shape, TensorShape indices_shape, TensorShape out_shape, DataType data_type, ScatterInfo scatter_info, QuantizationInfo src_qinfo = QuantizationInfo(), QuantizationInfo o_qinfo = QuantizationInfo())
+    {
+        _target    = compute_target(src_shape, updates_shape, indices_shape,  out_shape, data_type, scatter_info, src_qinfo, o_qinfo);
+        _reference = compute_reference(src_shape, updates_shape, indices_shape,  out_shape, data_type,scatter_info, src_qinfo , o_qinfo);
+    }
+
+protected:
+    template <typename U>
+    void fill(U &&tensor, int i, float lo = -1.f, float hi = 1.f)
+    {
+        switch(tensor.data_type())
+        {
+            case DataType::F32:
+            {
+                std::uniform_real_distribution<float> distribution(lo, hi);
+                library->fill(tensor, distribution, i);
+                break;
+            }
+            default:
+            {
+                ARM_COMPUTE_ERROR("Unsupported data type.");
+            }
+        }
+    }
+
+    TensorType compute_target(const TensorShape &shape_a, const TensorShape &shape_b, const TensorShape &shape_c, const TensorShape &out_shape, DataType data_type, const ScatterInfo info, QuantizationInfo a_qinfo, QuantizationInfo o_qinfo)
+    {
+        // 1. Create relevant tensors using ScatterInfo data structure.
+        // ----------------------------------------------------
+        // In order - src, updates, indices, output.
+        TensorType src   = create_tensor<TensorType>(shape_a, data_type, 1, a_qinfo);
+        TensorType updates   = create_tensor<TensorType>(shape_b, data_type, 1, a_qinfo);
+        TensorType indices   = create_tensor<TensorType>(shape_c, DataType::U32, 1, QuantizationInfo());
+        TensorType dst = create_tensor<TensorType>(out_shape, data_type, 1, o_qinfo);
+
+        FunctionType scatter;
+
+        // Configure operator
+        scatter.configure(&src, &updates, &indices, &dst, info);
+
+        // Assertions
+        ARM_COMPUTE_ASSERT(src.info()->is_resizable());
+        ARM_COMPUTE_ASSERT(updates.info()->is_resizable());
+        ARM_COMPUTE_ASSERT(indices.info()->is_resizable());
+        ARM_COMPUTE_ASSERT(dst.info()->is_resizable());
+
+        // Allocate tensors
+        src.allocator()->allocate();
+        updates.allocator()->allocate();
+        indices.allocator()->allocate();
+        dst.allocator()->allocate();
+
+        ARM_COMPUTE_ASSERT(!src.info()->is_resizable());
+        ARM_COMPUTE_ASSERT(!updates.info()->is_resizable());
+        ARM_COMPUTE_ASSERT(!indices.info()->is_resizable());
+        ARM_COMPUTE_ASSERT(!dst.info()->is_resizable());
+
+        // Fill update (a) and indices (b) tensors.
+        fill(AccessorType(src), 0);
+        fill(AccessorType(updates), 1);
+        fill(AccessorType(indices), 2);
+
+        scatter.run();
+
+        return dst;
+    }
+
+    SimpleTensor<T> compute_reference(const TensorShape &a_shape, const TensorShape &b_shape, const TensorShape &c_shape, const TensorShape &out_shape, DataType data_type,
+                                      ScatterInfo info, QuantizationInfo a_qinfo, QuantizationInfo o_qinfo)
+    {
+        // Output Quantization not currently in use - fixture should be extended to support this.
+        ARM_COMPUTE_UNUSED(o_qinfo);
+
+        // Create reference tensors
+        SimpleTensor<T> src{ a_shape, data_type, 1, a_qinfo };
+        SimpleTensor<T> updates{b_shape, data_type, 1, QuantizationInfo() };
+        SimpleTensor<uint32_t> indices{ c_shape, DataType::U32, 1, QuantizationInfo() };
+
+        // Fill reference
+        fill(src, 0);
+        fill(updates, 1);
+        fill(indices, 2);
+
+        // Calculate individual reference.
+        auto result = reference::scatter_layer<T>(src, updates, indices, out_shape, info);
+
+        return result;
+    }
+
+    TensorType      _target{};
+    SimpleTensor<T> _reference{};
+};
+
+// This fixture will use the same shape for updates as indices.
+template <typename TensorType, typename AccessorType, typename FunctionType, typename T>
+class ScatterValidationFixture : public ScatterGenericValidationFixture<TensorType, AccessorType, FunctionType, T>
+{
+public:
+    void setup(TensorShape src_shape, TensorShape indices_shape,  TensorShape out_shape, DataType data_type, ScatterFunction func, bool zero_init)
+    {
+        ScatterGenericValidationFixture<TensorType, AccessorType, FunctionType, T>::setup(src_shape, indices_shape, indices_shape, out_shape, data_type, ScatterInfo(func, zero_init), QuantizationInfo(), QuantizationInfo());
+    }
+};
+
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif // ACL_TESTS_VALIDATION_FIXTURES_SCATTERLAYERFIXTURE_H
diff --git a/tests/validation/reference/ScatterLayer.cpp b/tests/validation/reference/ScatterLayer.cpp
new file mode 100644
index 0000000..188cce1
--- /dev/null
+++ b/tests/validation/reference/ScatterLayer.cpp
@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2024 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include "ScatterLayer.h"
+#include "tests/validation/Helpers.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+
+template <typename T>
+SimpleTensor<T> scatter_layer_internal(const SimpleTensor<T> &src, const SimpleTensor<T> &updates, const SimpleTensor<uint32_t> &indices, const TensorShape &out_shape, const ScatterInfo &info)
+{
+    ARM_COMPUTE_UNUSED(src);
+    ARM_COMPUTE_UNUSED(updates);
+    ARM_COMPUTE_UNUSED(indices);
+    ARM_COMPUTE_UNUSED(info);
+    // Unimplemented reference.
+    SimpleTensor<T> dst{ out_shape, src.data_type(), 1 };
+    return dst;
+}
+
+template <typename T>
+SimpleTensor<T> scatter_layer(const SimpleTensor<T> &src, const SimpleTensor<T> &updates, const SimpleTensor<uint32_t> &indices, const TensorShape &out_shape, const ScatterInfo &info)
+{
+    return scatter_layer_internal<T>(src, updates, indices, out_shape, info);
+}
+
+template SimpleTensor<float> scatter_layer(const SimpleTensor<float> &src, const SimpleTensor<float> &updates, const SimpleTensor<uint32_t> &indices, const TensorShape &out_shape, const ScatterInfo &info);
+
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/reference/ScatterLayer.h b/tests/validation/reference/ScatterLayer.h
new file mode 100644
index 0000000..dc441a8
--- /dev/null
+++ b/tests/validation/reference/ScatterLayer.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2024 Arm Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef ACL_TESTS_VALIDATION_REFERENCE_SCATTERLAYER_H
+#define ACL_TESTS_VALIDATION_REFERENCE_SCATTERLAYER_H
+
+#include "Utils.h"
+#include "arm_compute/function_info/ScatterInfo.h"
+#include "tests/SimpleTensor.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T>
+SimpleTensor<T> scatter_layer_internal(const SimpleTensor<T> &src, const SimpleTensor<T> &update, const SimpleTensor<uint32_t> &indices, const TensorShape &shape, const ScatterInfo &info);
+
+template <typename T>
+SimpleTensor<T> scatter_layer(const SimpleTensor<T> &src, const SimpleTensor<T> &update, const SimpleTensor<uint32_t> &indices, const TensorShape &shape, const ScatterInfo &info);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif // ACL_TESTS_VALIDATION_REFERENCE_SCATTERLAYER_H