COMPMID-1960: Implement DFT reference

Change-Id: I08d47ce2cf7fc833df94420bedd69cedf080fd34
Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Reviewed-on: https://review.mlplatform.org/c/822
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
diff --git a/tests/validation/reference/DFT.h b/tests/validation/reference/DFT.h
new file mode 100644
index 0000000..a3a10ab
--- /dev/null
+++ b/tests/validation/reference/DFT.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2019 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_FFT_H__
+#define __ARM_COMPUTE_TEST_FFT_H__
+
+#include "tests/SimpleTensor.h"
+#include "tests/validation/Helpers.h"
+
+namespace arm_compute
+{
+namespace test
+{
+namespace validation
+{
+namespace reference
+{
+enum class FFTDirection
+{
+    Forward,
+    Inverse
+};
+
+/** Performs an one dimensional DFT on a real input.
+ *
+ * @param[in] src Source tensor.
+ *
+ * @return Complex output of length n/2 + 1 due to symmetry.
+ */
+template <typename T>
+SimpleTensor<T> rdft_1d(const SimpleTensor<T> &src);
+
+/** Performs an one dimensional inverse DFT on a real input.
+ *
+ * @param[in] src    Source tensor.
+ * @param[in] is_odd (Optional) Specifies if the output has odd dimensions.
+ *                   Is used by the inverse variant to reconstruct odd sequences.
+ *
+ * @return Complex output of length n/2 + 1 due to symmetry.
+ */
+template <typename T>
+SimpleTensor<T> ridft_1d(const SimpleTensor<T> &src, bool is_odd = false);
+
+/**  Performs an one dimensional DFT on a complex input.
+ *
+ * @param[in] src       Source tensor.
+ * @param[in] direction Direction of the DFT.
+ *
+ * @return Complex output of same length as input.
+ */
+template <typename T>
+SimpleTensor<T> dft_1d(const SimpleTensor<T> &src, FFTDirection direction);
+
+/** Performs a two dimensional DFT on a real input.
+ *
+ * @param[in] src Source tensor.
+ *
+ * @return Complex output of length n/2 + 1 across width due to symmetry and height of same size as the input.
+ */
+template <typename T>
+SimpleTensor<T> rdft_2d(const SimpleTensor<T> &src);
+
+/** Performs a two dimensional inverse DFT on a real input.
+ *
+ * @param[in] src    Source tensor.
+ * @param[in] is_odd (Optional) Specifies if the output has odd dimensions across width.
+ *                   Is used by the inverse variant to reconstruct odd sequences.
+ *
+ * @return Complex output of length n/2 + 1 across width due to symmetry and height of same size as the input.
+ */
+template <typename T>
+SimpleTensor<T> ridft_2d(const SimpleTensor<T> &src, bool is_odd = false);
+
+/**  Performs a two dimensional DFT on a complex input.
+ *
+ * @param[in] src       Source tensor.
+ * @param[in] direction Direction of the DFT.
+ *
+ * @return Complex output of same length as input.
+ */
+template <typename T>
+SimpleTensor<T> dft_2d(const SimpleTensor<T> &src, FFTDirection direction);
+
+/** Performs and DFT based convolution on a real input.
+ *
+ * @param[in] src       Source tensor.
+ * @param[in] w         Weights tensor.
+ * @param[in] conv_info Convolution related metadata.
+ *
+ * @return The output tensor.
+ */
+template <typename T>
+SimpleTensor<T> conv2d_dft(const SimpleTensor<T> &src, const SimpleTensor<T> &w, const PadStrideInfo &conv_info);
+} // namespace reference
+} // namespace validation
+} // namespace test
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_TEST_FFT_H__ */