COMPMID-1958: Implements 1D FFT in OpenCL.

Forward complex FFT implementation.

Change-Id: Ia0ba8740072e5adb06f8ead462a47abc8b5dd125
Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Reviewed-on: https://review.mlplatform.org/c/904
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/arm_compute/core/utils/helpers/fft.h b/arm_compute/core/utils/helpers/fft.h
new file mode 100644
index 0000000000..bd84a5c63d
--- /dev/null
+++ b/arm_compute/core/utils/helpers/fft.h
@@ -0,0 +1,55 @@
+/*
+ * 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_UTILS_HELPERS_FFT_H__
+#define __ARM_COMPUTE_UTILS_HELPERS_FFT_H__
+
+#include <set>
+#include <vector>
+
+namespace arm_compute
+{
+namespace helpers
+{
+namespace fft
+{
+/** Decompose a given 1D input size using the provided supported factors.
+ *
+ * @param[in] N                 Input size to be decomposed.
+ * @param[in] supported_factors Supported factors that can be used for decomposition.
+ *
+ * @return A vector with the stages of the decomposition. Will be empty if decomposition failed.
+ */
+std::vector<unsigned int> decompose_stages(unsigned int N, const std::set<unsigned int> &supported_factors);
+/** Calculate digit reverse index vector given fft size and the decomposed stages
+ *
+ * @param N          Input size to calculate digit reverse for
+ * @param fft_stages A vector with the FFT decomposed stages
+ *
+ * @return A vector with the digit reverse indices. Will be empty if it failed.
+ */
+std::vector<unsigned int> digit_reverse_indices(unsigned int N, const std::vector<unsigned int> &fft_stages);
+} // namespace fft
+} // namespace helpers
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_UTILS_HELPERS_FFT_H__ */