COMPMID-583 - Implemented reference implementation and validation tests (NEON and CL) for Histogram

Change-Id: Iccf6b4483cb8394dab2f861a737583126f9bed81
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/91601
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>

8 files changed, 484 insertions, 13 deletions

diff --git a/src/core/CL/kernels/CLHistogramKernel.cpp b/src/core/CL/kernels/CLHistogramKernel.cpp
index 87ee5fb74e..7b715abb36 100644
--- a/src/core/CL/kernels/CLHistogramKernel.cpp
+++ b/src/core/CL/kernels/CLHistogramKernel.cpp
@@ -115,18 +115,20 @@ void CLHistogramKernel::run(const Window &window, cl::CommandQueue &queue)
     ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
     ARM_COMPUTE_ERROR_ON_MISMATCHING_WINDOWS(ICLKernel::window(), window);
 
-    if(_input->info()->dimension(0) < pixels_per_item)
-    {
-        return;
-    }
-
+    // TODO (COMPMID-679): Add CLMemFill
     _output->map(queue, true);
     ARM_COMPUTE_ERROR_ON(_output->buffer() == nullptr);
     memset(_output->buffer(), 0, _output->size());
     _output->unmap(queue);
 
-    Window      slice = window.first_slice_window_2D();
-    cl::NDRange lws   = cl::NDRange(local_x_size, 1);
+    if(_input->info()->dimension(0) < pixels_per_item)
+    {
+        return;
+    }
+
+    Window             slice = window.first_slice_window_2D();
+    const unsigned int gws_x = (window.x().end() - window.x().start()) / window.x().step();
+    cl::NDRange        lws   = (local_x_size < gws_x) ? cl::NDRange(local_x_size, 1) : cl::NDRange(1, 1);
 
     do
     {
diff --git a/src/core/NEON/kernels/NEHistogramKernel.cpp b/src/core/NEON/kernels/NEHistogramKernel.cpp
index 6e402ae604..02de566f6a 100644
--- a/src/core/NEON/kernels/NEHistogramKernel.cpp
+++ b/src/core/NEON/kernels/NEHistogramKernel.cpp
@@ -87,8 +87,8 @@ void NEHistogramKernel::histogram_U8(Window win, const ThreadInfo &info)
         }
     };
 
-    const unsigned int x_start = win.x().start();
-    const unsigned int x_end   = win.x().end();
+    const int x_start = win.x().start();
+    const int x_end   = win.x().end();
 
     // Handle X dimension manually to split into two loops
     // First one will use vector operations, second one processes the left over
@@ -100,7 +100,7 @@ void NEHistogramKernel::histogram_U8(Window win, const ThreadInfo &info)
     // Calculate local histogram
     execute_window_loop(win, [&](const Coordinates &)
     {
-        unsigned int x = x_start;
+        int x = x_start;
 
         // Vector loop
         for(; x <= x_end - 8; x += 8)
@@ -136,8 +136,8 @@ void NEHistogramKernel::histogram_fixed_U8(Window win, const ThreadInfo &info)
 
     std::array<uint32_t, _max_range_size> local_hist{ { 0 } };
 
-    const unsigned int x_start = win.x().start();
-    const unsigned int x_end   = win.x().end();
+    const int x_start = win.x().start();
+    const int x_end   = win.x().end();
 
     // Handle X dimension manually to split into two loops
     // First one will use vector operations, second one processes the left over
@@ -149,7 +149,7 @@ void NEHistogramKernel::histogram_fixed_U8(Window win, const ThreadInfo &info)
     // Calculate local histogram
     execute_window_loop(win, [&](const Coordinates &)
     {
-        unsigned int x = x_start;
+        int x = x_start;
 
         // Vector loop
         for(; x <= x_end - 8; x += 8)
diff --git a/tests/validation/CL/Histogram.cpp b/tests/validation/CL/Histogram.cpp
new file mode 100644
index 0000000000..318bc1e3ab
--- /dev/null
+++ b/tests/validation/CL/Histogram.cpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2017 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/core/Types.h"
+#include "arm_compute/runtime/CL/CLDistribution1D.h"
+#include "arm_compute/runtime/CL/functions/CLHistogram.h"
+#include "arm_compute/runtime/Tensor.h"
+#include "arm_compute/runtime/TensorAllocator.h"
+#include "tests/CL/CLAccessor.h"
+#include "tests/PaddingCalculator.h"
+#include "tests/datasets/BorderModeDataset.h"
+#include "tests/datasets/ShapeDatasets.h"
+#include "tests/framework/Asserts.h"
+#include "tests/framework/Macros.h"
+#include "tests/framework/datasets/Datasets.h"
+#include "tests/validation/Validation.h"
+#include "tests/validation/fixtures/HistogramFixture.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+TEST_SUITE(CL)
+TEST_SUITE(Histogram)
+
+DATA_TEST_CASE(Configuration, framework::DatasetMode::ALL, combine(concat(datasets::Small2DShapes(), datasets::Large2DShapes()),
+                                                                   framework::dataset::make("DataType", DataType::U8)),
+               shape, data_type)
+{
+    // Setup Distribution
+    std::mt19937                            gen(library->seed());
+    std::uniform_int_distribution<size_t>   distribution_size_t(1, 30);
+    const size_t                            num_bins = distribution_size_t(gen);
+    std::uniform_int_distribution<int32_t>  distribution_int32_t(0, 125);
+    const size_t                            offset = distribution_int32_t(gen);
+    std::uniform_int_distribution<uint32_t> distribution_uint32_t(1, 255 - offset);
+    const size_t                            range = distribution_uint32_t(gen);
+    CLDistribution1D                        distribution_dst(num_bins, offset, range);
+
+    // Create tensors
+    CLTensor    src = create_tensor<CLTensor>(shape, data_type);
+    TensorShape dst_shape(num_bins);
+    CLTensor    dst = create_tensor<CLTensor>(dst_shape, DataType::U32);
+
+    ARM_COMPUTE_EXPECT(src.info()->is_resizable(), framework::LogLevel::ERRORS);
+    ARM_COMPUTE_EXPECT(dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+    // Create and configure function
+    CLHistogram histogram;
+    histogram.configure(&src, &distribution_dst);
+
+    // Validate valid region
+    const ValidRegion valid_region = shape_to_valid_region(shape);
+    validate(src.info()->valid_region(), valid_region);
+    const ValidRegion valid_region_dst = shape_to_valid_region(dst_shape);
+    validate(dst.info()->valid_region(), valid_region_dst);
+
+    // Validate padding
+    const PaddingSize padding;
+    validate(src.info()->padding(), padding);
+    validate(dst.info()->padding(), padding);
+}
+
+template <typename T>
+using CLHistogramFixture = HistogramValidationFixture<CLTensor, CLAccessor, CLHistogram, T, CLDistribution1D>;
+
+FIXTURE_DATA_TEST_CASE(RunSmall, CLHistogramFixture<uint8_t>, framework::DatasetMode::PRECOMMIT, combine(datasets::Small2DShapes(), framework::dataset::make("DataType",
+                                                                                                         DataType::U8)))
+{
+    // Validate output
+    validate(CLAccessor(_target), _reference);
+}
+FIXTURE_DATA_TEST_CASE(RunLarge, CLHistogramFixture<uint8_t>, framework::DatasetMode::NIGHTLY, combine(datasets::Large2DShapes(), framework::dataset::make("DataType",
+                                                                                                       DataType::U8)))
+{
+    // Validate output
+    validate(CLAccessor(_target), _reference);
+}
+
+TEST_SUITE_END()
+TEST_SUITE_END()
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/CPP/Histogram.cpp b/tests/validation/CPP/Histogram.cpp
new file mode 100644
index 0000000000..594c4fb81f
--- /dev/null
+++ b/tests/validation/CPP/Histogram.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2017 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 "Histogram.h"
+
+#include "Utils.h"
+#include "arm_compute/core/Helpers.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T>
+SimpleTensor<uint32_t> histogram(const SimpleTensor<T> &src, size_t num_bins, int32_t offset, uint32_t range)
+{
+    SimpleTensor<uint32_t> dst(TensorShape(num_bins), DataType::U32);
+
+    // Clear the distribution
+    for(size_t element_idx = 0; element_idx < num_bins; ++element_idx)
+    {
+        dst[element_idx] = 0;
+    }
+
+    // Create the histogram
+    for(int element_idx = 0; element_idx < src.num_elements(); ++element_idx)
+    {
+        if((offset <= src[element_idx]) && (src[element_idx] < (offset + range)))
+        {
+            const int index = (src[element_idx] - offset) * num_bins / range;
+            dst[index]++;
+        }
+    }
+
+    return dst;
+}
+
+template SimpleTensor<uint32_t> histogram(const SimpleTensor<uint8_t> &src, size_t num_bins, int32_t offset, uint32_t range);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/CPP/Histogram.h b/tests/validation/CPP/Histogram.h
new file mode 100644
index 0000000000..7ec16693aa
--- /dev/null
+++ b/tests/validation/CPP/Histogram.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2017 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 __ARM_COMPUTE_TEST_HISTOGRAM_H__
+#define __ARM_COMPUTE_TEST_HISTOGRAM_H__
+
+#include "tests/SimpleTensor.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+template <typename T>
+SimpleTensor<uint32_t> histogram(const SimpleTensor<T> &src, size_t num_bins, int32_t offset, uint32_t range);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_TEST_HISTOGRAM_H__ */
diff --git a/tests/validation/NEON/Histogram.cpp b/tests/validation/NEON/Histogram.cpp
new file mode 100644
index 0000000000..d2b53b790c
--- /dev/null
+++ b/tests/validation/NEON/Histogram.cpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2017 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/core/Types.h"
+#include "arm_compute/runtime/Distribution1D.h"
+#include "arm_compute/runtime/NEON/functions/NEHistogram.h"
+#include "arm_compute/runtime/Tensor.h"
+#include "arm_compute/runtime/TensorAllocator.h"
+#include "tests/NEON/Accessor.h"
+#include "tests/PaddingCalculator.h"
+#include "tests/datasets/BorderModeDataset.h"
+#include "tests/datasets/ShapeDatasets.h"
+#include "tests/framework/Asserts.h"
+#include "tests/framework/Macros.h"
+#include "tests/framework/datasets/Datasets.h"
+#include "tests/validation/Validation.h"
+#include "tests/validation/fixtures/HistogramFixture.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+TEST_SUITE(NEON)
+TEST_SUITE(Histogram)
+
+DATA_TEST_CASE(Configuration, framework::DatasetMode::ALL, combine(concat(datasets::Small2DShapes(), datasets::Large2DShapes()),
+                                                                   framework::dataset::make("DataType", DataType::U8)),
+               shape, data_type)
+{
+    // Setup Distribution
+    std::mt19937                            gen(library->seed());
+    std::uniform_int_distribution<size_t>   distribution_size_t(1, 30);
+    const size_t                            num_bins = distribution_size_t(gen);
+    std::uniform_int_distribution<int32_t>  distribution_int32_t(0, 125);
+    const size_t                            offset = distribution_int32_t(gen);
+    std::uniform_int_distribution<uint32_t> distribution_uint32_t(1, 255 - offset);
+    const size_t                            range = distribution_uint32_t(gen);
+    Distribution1D                          distribution_dst(num_bins, offset, range);
+
+    // Create tensors
+    Tensor      src = create_tensor<Tensor>(shape, data_type);
+    TensorShape dst_shape(num_bins);
+    Tensor      dst = create_tensor<Tensor>(dst_shape, DataType::U32);
+
+    ARM_COMPUTE_EXPECT(src.info()->is_resizable(), framework::LogLevel::ERRORS);
+    ARM_COMPUTE_EXPECT(dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+    // Create and configure function
+    NEHistogram histogram;
+    histogram.configure(&src, &distribution_dst);
+
+    // Validate valid region
+    const ValidRegion valid_region = shape_to_valid_region(shape);
+    validate(src.info()->valid_region(), valid_region);
+    const ValidRegion valid_region_dst = shape_to_valid_region(dst_shape);
+    validate(dst.info()->valid_region(), valid_region_dst);
+
+    // Validate padding
+    const PaddingSize padding;
+    validate(src.info()->padding(), padding);
+    validate(dst.info()->padding(), padding);
+}
+
+template <typename T>
+using NEHistogramFixture = HistogramValidationFixture<Tensor, Accessor, NEHistogram, T, Distribution1D>;
+
+FIXTURE_DATA_TEST_CASE(RunSmall, NEHistogramFixture<uint8_t>, framework::DatasetMode::PRECOMMIT, combine(datasets::Small2DShapes(), framework::dataset::make("DataType",
+                                                                                                         DataType::U8)))
+{
+    // Validate output
+    validate(Accessor(_target), _reference);
+}
+FIXTURE_DATA_TEST_CASE(RunLarge, NEHistogramFixture<uint8_t>, framework::DatasetMode::NIGHTLY, combine(datasets::Large2DShapes(), framework::dataset::make("DataType",
+                                                                                                       DataType::U8)))
+{
+    // Validate output
+    validate(Accessor(_target), _reference);
+}
+
+TEST_SUITE_END()
+TEST_SUITE_END()
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
diff --git a/tests/validation/fixtures/HistogramFixture.h b/tests/validation/fixtures/HistogramFixture.h
new file mode 100644
index 0000000000..943b2cdde3
--- /dev/null
+++ b/tests/validation/fixtures/HistogramFixture.h
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2017 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 ARM_COMPUTE_TEST_HISTOGRAM_FIXTURE
+#define ARM_COMPUTE_TEST_HISTOGRAM_FIXTURE
+
+#include "arm_compute/core/TensorShape.h"
+#include "arm_compute/core/Types.h"
+#include "tests/AssetsLibrary.h"
+#include "tests/Globals.h"
+#include "tests/IAccessor.h"
+#include "tests/framework/Asserts.h"
+#include "tests/framework/Fixture.h"
+#include "tests/validation/CPP/Histogram.h"
+#include "utils/Utils.h"
+
+#include <random>
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+template <typename TensorType, typename AccessorType, typename FunctionType, typename T, typename DistributionType>
+class HistogramValidationFixture : public framework::Fixture
+{
+public:
+    template <typename...>
+    void setup(TensorShape shape, DataType data_type)
+    {
+        std::mt19937                            gen(library->seed());
+        std::uniform_int_distribution<size_t>   distribution_size_t(1, 30);
+        const size_t                            num_bins = distribution_size_t(gen);
+        std::uniform_int_distribution<int32_t>  distribution_int32_t(0, 125);
+        const size_t                            offset = distribution_int32_t(gen);
+        std::uniform_int_distribution<uint32_t> distribution_uint32_t(1, 255 - offset);
+        const size_t                            range = distribution_uint32_t(gen);
+
+        _target    = compute_target(shape, data_type, num_bins, offset, range);
+        _reference = compute_reference(shape, data_type, num_bins, offset, range);
+    }
+
+protected:
+    template <typename U>
+    void fill(U &&tensor)
+    {
+        library->fill_tensor_uniform(tensor, 0);
+    }
+
+    TensorType compute_target(const TensorShape &shape, DataType data_type, size_t num_bins, int32_t offset, uint32_t range)
+    {
+        // Create tensors
+        TensorType       src = create_tensor<TensorType>(shape, data_type);
+        TensorType       dst = create_tensor<TensorType>(TensorShape(num_bins), DataType::U32);
+        DistributionType distribution_dst(num_bins, offset, range);
+
+        // Create and configure function
+        FunctionType histogram;
+        histogram.configure(&src, &distribution_dst);
+        ARM_COMPUTE_EXPECT(src.info()->is_resizable(), framework::LogLevel::ERRORS);
+        ARM_COMPUTE_EXPECT(dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+        // Allocate tensors
+        src.allocator()->allocate();
+        dst.allocator()->allocate();
+
+        ARM_COMPUTE_EXPECT(!src.info()->is_resizable(), framework::LogLevel::ERRORS);
+        ARM_COMPUTE_EXPECT(!dst.info()->is_resizable(), framework::LogLevel::ERRORS);
+
+        // Fill tensors
+        fill(AccessorType(src));
+
+        // Compute function
+        histogram.run();
+
+        // Copy the distribution in a tensor
+        arm_compute::utils::map(distribution_dst, true);
+        AccessorType accessor_dst = AccessorType(dst);
+        uint32_t    *dst_data     = static_cast<uint32_t *>(accessor_dst.data());
+
+        ARM_COMPUTE_EXPECT(accessor_dst.size() <= dst.info()->total_size(), framework::LogLevel::ERRORS);
+
+        std::copy_n(distribution_dst.buffer(), num_bins, dst_data);
+        arm_compute::utils::unmap(distribution_dst);
+        return dst;
+    }
+
+    SimpleTensor<uint32_t> compute_reference(const TensorShape &shape, DataType data_type, size_t num_bins, int32_t offset, uint32_t range)
+    {
+        ARM_COMPUTE_ERROR_ON(data_type != DataType::U8);
+
+        // Create reference
+        SimpleTensor<T> src{ shape, data_type };
+
+        // Fill reference
+        fill(src);
+
+        // Compute reference
+        return reference::histogram<T>(src, num_bins, offset, range);
+    }
+
+    TensorType             _target{};
+    SimpleTensor<uint32_t> _reference{};
+};
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif /* ARM_COMPUTE_TEST_HISTOGRAM_FIXTURE */
diff --git a/utils/Utils.h b/utils/Utils.h
index 4e5bc815ab..9d2b517708 100644
--- a/utils/Utils.h
+++ b/utils/Utils.h
@@ -35,6 +35,7 @@
 
 #ifdef ARM_COMPUTE_CL
 #include "arm_compute/core/CL/OpenCL.h"
+#include "arm_compute/runtime/CL/CLDistribution1D.h"
 #include "arm_compute/runtime/CL/CLTensor.h"
 #endif /* ARM_COMPUTE_CL */
 #ifdef ARM_COMPUTE_GC
@@ -189,6 +190,25 @@ inline void unmap(CLTensor &tensor)
 {
     tensor.unmap();
 }
+
+/** Maps a distribution if needed
+ *
+ * @param[in] distribution Distribution to be mapped
+ * @param[in] blocking     Specified if map is blocking or not
+ */
+inline void map(CLDistribution1D &distribution, bool blocking)
+{
+    distribution.map(blocking);
+}
+
+/** Unmaps a distribution if needed
+ *
+ * @param distribution  Distribution to be unmapped
+ */
+inline void unmap(CLDistribution1D &distribution)
+{
+    distribution.unmap();
+}
 #endif /* ARM_COMPUTE_CL */
 
 #ifdef ARM_COMPUTE_GC