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>

5 files changed, 1446 insertions, 4 deletions

diff --git a/src/core/CL/CLKernelLibrary.cpp b/src/core/CL/CLKernelLibrary.cpp
index 0c895ce5c6..818039c184 100644
--- a/src/core/CL/CLKernelLibrary.cpp
+++ b/src/core/CL/CLKernelLibrary.cpp
@@ -219,6 +219,7 @@ const std::map<std::string, std::string> CLKernelLibrary::_kernel_program_map =
     { "depthwise_convolution_3x3_f16", "depthwise_convolution.cl" },
     { "depthwise_convolution_3x3_nhwc", "depthwise_convolution.cl" },
     { "depthwise_convolution_3x3_nhwc_stride1", "depthwise_convolution.cl" },
+    { "digit_reverse", "fft.cl" },
     { "dwc_3x3_native_qasymm8_nchw", "depthwise_convolution_quantized.cl" },
     { "dwc_3x3_native_qasymm8_dot8_nchw", "depthwise_convolution_quantized.cl" },
     { "dwc_3x3_reshaped_qasymm8_nhwc", "depthwise_convolution_quantized.cl" },
@@ -260,12 +261,24 @@ const std::map<std::string, std::string> CLKernelLibrary::_kernel_program_map =
     { "elementwise_unary", "elementwise_unary.cl" },
     { "erode", "erode.cl" },
     { "fast_corners", "fast_corners.cl" },
-    { "flatten", "flatten.cl" },
+    { "fft_radix_2_first_stage_axis_0", "fft.cl" },
+    { "fft_radix_2_axis_0", "fft.cl" },
+    { "fft_radix_3_first_stage_axis_0", "fft.cl" },
+    { "fft_radix_3_axis_0", "fft.cl" },
+    { "fft_radix_4_first_stage_axis_0", "fft.cl" },
+    { "fft_radix_4_axis_0", "fft.cl" },
+    { "fft_radix_5_first_stage_axis_0", "fft.cl" },
+    { "fft_radix_5_axis_0", "fft.cl" },
+    { "fft_radix_7_first_stage_axis_0", "fft.cl" },
+    { "fft_radix_7_axis_0", "fft.cl" },
+    { "fft_radix_8_first_stage_axis_0", "fft.cl" },
+    { "fft_radix_8_axis_0", "fft.cl" },
     { "fill_image_borders_constant", "fill_border.cl" },
     { "fill_image_borders_replicate", "fill_border.cl" },
     { "finalize", "optical_flow_pyramid_lk.cl" },
-    { "fuse_batchnormalization_layer", "batchnormalization_layer.cl" },
+    { "flatten", "flatten.cl" },
     { "floor_layer", "floor.cl" },
+    { "fuse_batchnormalization_layer", "batchnormalization_layer.cl" },
     { "gather", "gather.cl" },
     { "gaussian1x5_sub_x", "gaussian_pyramid.cl" },
     { "gaussian5x1_sub_y", "gaussian_pyramid.cl" },
@@ -686,14 +699,18 @@ const std::map<std::string, std::string> CLKernelLibrary::_program_source_map =
 #include "./cl_kernels/fast_corners.clembed"
     },
     {
-        "flatten.cl",
-#include "./cl_kernels/flatten.clembed"
+        "fft.cl",
+#include "./cl_kernels/fft.clembed"
     },
     {
         "fill_border.cl",
 #include "./cl_kernels/fill_border.clembed"
     },
     {
+        "flatten.cl",
+#include "./cl_kernels/flatten.clembed"
+    },
+    {
         "floor.cl",
 #include "./cl_kernels/floor.clembed"
     },
diff --git a/src/core/CL/cl_kernels/fft.cl b/src/core/CL/cl_kernels/fft.cl
new file mode 100644
index 0000000000..5f1ef2483b
--- /dev/null
+++ b/src/core/CL/cl_kernels/fft.cl
@@ -0,0 +1,1014 @@
+/*
+ * 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.
+ */
+#include "helpers.h"
+
+/** Computes the digit reverse stage
+ *
+ * @param[in]  src_ptr                           Pointer to the source tensor. Supported data types: F32
+ * @param[in]  src_stride_x                      Stride of the source tensor in X dimension (in bytes)
+ * @param[in]  src_step_x                        src_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]  src_stride_y                      Stride of the source tensor in Y dimension (in bytes)
+ * @param[in]  src_step_y                        src_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]  src_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]  src_step_z                        src_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]  src_offset_first_element_in_bytes The offset of the first element in the source tensor
+ * @param[out] dst_ptr                           Pointer to the destination tensor. Supported data types: same as @p src_ptr
+ * @param[in]  dst_stride_x                      Stride of the destination tensor in X dimension (in bytes)
+ * @param[in]  dst_step_x                        dst_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]  dst_stride_y                      Stride of the destination tensor in Y dimension (in bytes)
+ * @param[in]  dst_step_y                        dst_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]  dst_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]  dst_step_z                        dst_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]  dst_offset_first_element_in_bytes The offset of the first element in the destination tensor
+ * @param[in]  idx_ptr                           Pointer to the index tensor. Supported data types: U32
+ * @param[in]  idx_stride_x                      Stride of the index tensor in X dimension (in bytes)
+ * @param[in]  idx_step_x                        idx_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]  idx_offset_first_element_in_bytes The offset of the first element in the index tensor
+ */
+__kernel void digit_reverse(
+    TENSOR3D_DECLARATION(src),
+    TENSOR3D_DECLARATION(dst),
+    VECTOR_DECLARATION(idx))
+{
+    // Get tensor pointers
+    Tensor3D src = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(src);
+    Tensor3D dst = CONVERT_TO_TENSOR3D_STRUCT(dst);
+    Vector   idx = CONVERT_TO_VECTOR_STRUCT(idx);
+
+    const unsigned int iidx = *((__global uint *)(idx.ptr));
+
+    // Load data
+    float2 data = vload2(0, (__global float *)tensor3D_offset(&src, iidx, get_global_id(1), get_global_id(2)));
+
+    // Store result
+    vstore2(data, 0, (__global float *)dst.ptr);
+}
+
+/** Calculates and applies the twiddle factor to a given input.
+ *
+ * @param[in]     phi   The angle.
+ * @param[in,out] input The input on which the factor should be applied.
+ */
+#define TWIDDLE_FACTOR_MULTIPLICATION(phi, input)  \
+    {                                              \
+        float2 w, tmp;                             \
+        w.x   = native_cos(phi);                   \
+        w.y   = native_sin(phi);                   \
+        tmp.x = (w.x * input.x) - (w.y * input.y); \
+        tmp.y = (w.x * input.y) + (w.y * input.x); \
+        input = tmp;                               \
+    }
+
+/** Computes radix-2 butterfly unit.
+ *
+ * @param[in,out] c0 Complex input 0.
+ * @param[in,out] c1 Complex input 1.
+ */
+#define DFT_2(c0, c1) \
+    {                 \
+        float2 v0;    \
+        v0 = c0;      \
+        c0 = v0 + c1; \
+        c1 = v0 - c1; \
+    }
+
+// radix-3 butterfly unit factors
+#define SQRT3DIV2 0.86602540378443f
+
+/** Computes radix-3 butterfly unit.
+ *
+ * @param[in,out] c0 Complex input 0.
+ * @param[in,out] c1 Complex input 1.
+ * @param[in,out] c2 Complex input 2.
+ */
+#define DFT_3(c0, c1, c2)                                  \
+    {                                                      \
+        float2 v0 = c1 + c2;                               \
+        float2 v1 = c1 - c2;                               \
+        c1.x      = c0.x - 0.5f * v0.x + v1.y * SQRT3DIV2; \
+        c1.y      = c0.y - 0.5f * v0.y - v1.x * SQRT3DIV2; \
+        c2.x      = c0.x - 0.5f * v0.x - v1.y * SQRT3DIV2; \
+        c2.y      = c0.y - 0.5f * v0.y + v1.x * SQRT3DIV2; \
+        c0        = c0 + v0;                               \
+    }
+
+/**Computes radix-4 butterfly unit.
+ *
+ * @param[in,out] c0 Complex input 0.
+ * @param[in,out] c1 Complex input 1.
+ * @param[in,out] c2 Complex input 2.
+ * @param[in,out] c3 Complex input 3.
+ */
+#define DFT_4(c0, c1, c2, c3)  \
+    {                          \
+        float2 v0, v1, v2, v3; \
+        v0   = c0 + c2;        \
+        v1   = c1 + c3;        \
+        v2   = c0 - c2;        \
+        v3.x = c1.y - c3.y;    \
+        v3.y = c3.x - c1.x;    \
+        c0   = v0 + v1;        \
+        c2   = v0 - v1;        \
+        c1   = v2 + v3;        \
+        c3   = v2 - v3;        \
+    }
+
+// radix-5 butterfly unit factors
+#define W5_A 0.30901699437494f
+#define W5_B 0.95105651629515f
+#define W5_C 0.80901699437494f
+#define W5_D 0.58778525229247f
+
+/** Computes radix-5 butterfly unit.
+ *
+ * @param[in,out] c0 Complex input 0.
+ * @param[in,out] c1 Complex input 1.
+ * @param[in,out] c2 Complex input 2.
+ * @param[in,out] c3 Complex input 3.
+ * @param[in,out] c4 Complex input 4.
+ */
+#define DFT_5(c0, c1, c2, c3, c4)                 \
+    {                                             \
+        float2 v0, v1, v2, v3, v4;                \
+        v0 = c0;                                  \
+        v1 = W5_A * (c1 + c4) - W5_C * (c2 + c3); \
+        v2 = W5_C * (c1 + c4) - W5_A * (c2 + c3); \
+        v3 = W5_D * (c1 - c4) - W5_B * (c2 - c3); \
+        v4 = W5_B * (c1 - c4) + W5_D * (c2 - c3); \
+        c0 = v0 + c1 + c2 + c3 + c4;              \
+        c1 = v0 + v1 + (float2)(v4.y, -v4.x);     \
+        c2 = v0 - v2 + (float2)(v3.y, -v3.x);     \
+        c3 = v0 - v2 + (float2)(-v3.y, v3.x);     \
+        c4 = v0 + v1 + (float2)(-v4.y, v4.x);     \
+    }
+
+// radix-7 butterfly unit factors
+#define W7_A 0.62348980185873f
+#define W7_B 0.78183148246802f
+#define W7_C 0.22252093395631f
+#define W7_D 0.97492791218182f
+#define W7_E 0.90096886790241f
+#define W7_F 0.43388373911755f
+
+/** Computes radix-7 butterfly unit.
+ *
+ * @param[in,out] c0 Complex input 0.
+ * @param[in,out] c1 Complex input 1.
+ * @param[in,out] c2 Complex input 2.
+ * @param[in,out] c3 Complex input 3.
+ * @param[in,out] c4 Complex input 4.
+ * @param[in,out] c5 Complex input 5.
+ * @param[in,out] c6 Complex input 6.
+ */
+#define DFT_7(c0, c1, c2, c3, c4, c5, c6)                            \
+    {                                                                \
+        float2 v0, v1, v2, v3, v4, v5, v6;                           \
+        v0 = c0;                                                     \
+        v1 = W7_A * (c1 + c6) - W7_C * (c2 + c5) - W7_E * (c3 + c4); \
+        v2 = W7_C * (c1 + c6) + W7_E * (c2 + c5) - W7_A * (c3 + c4); \
+        v3 = W7_E * (c1 + c6) - W7_A * (c2 + c5) + W7_C * (c3 + c4); \
+        v4 = W7_B * (c1 - c6) + W7_D * (c2 - c5) + W7_F * (c3 - c4); \
+        v5 = W7_D * (c1 - c6) - W7_F * (c2 - c5) - W7_B * (c3 - c4); \
+        v6 = W7_F * (c1 - c6) - W7_B * (c2 - c5) + W7_D * (c3 - c4); \
+        c0 = v0 + c1 + c2 + c3 + c4 + c5 + c6;                       \
+        c1 = v0 + v1 + (float2)(v4.y, -v4.x);                        \
+        c2 = v0 - v2 + (float2)(v5.y, -v5.x);                        \
+        c3 = v0 - v3 + (float2)(v6.y, -v6.x);                        \
+        c4 = v0 - v3 + (float2)(-v6.y, v6.x);                        \
+        c5 = v0 - v2 + (float2)(-v5.y, v5.x);                        \
+        c6 = v0 + v1 + (float2)(-v4.y, v4.x);                        \
+    }
+
+/** Computes radix-8 butterfly unit.
+ *
+ * @param[in,out] c0 Complex input 0.
+ * @param[in,out] c1 Complex input 1.
+ * @param[in,out] c2 Complex input 2.
+ * @param[in,out] c3 Complex input 3.
+ * @param[in,out] c4 Complex input 4.
+ * @param[in,out] c5 Complex input 5.
+ * @param[in,out] c6 Complex input 6.
+ * @param[in,out] c7 Complex input 7.
+ */
+#define DFT_8(c0, c1, c2, c3, c4, c5, c6, c7)  \
+    {                                          \
+        float2 v0, v1, v2, v3, v4, v5, v6, v7; \
+        float2 s0, s1, s2, s3, s4, s5, s6, s7; \
+        float2 t0, t1, t2;                     \
+        v0   = c0 + c4;                        \
+        v1   = c1 + c5;                        \
+        v2   = c2 + c6;                        \
+        v3   = c3 + c7;                        \
+        v4   = c0 - c4;                        \
+        v5   = c1 - c5;                        \
+        v6   = c2 - c6;                        \
+        v7   = c3 - c7;                        \
+        s0   = v0 + v2;                        \
+        s1   = v1 + v3;                        \
+        s2   = v0 - v2;                        \
+        s3   = v1 - v3;                        \
+        s4.x = v4.x - v6.y;                    \
+        s4.y = v4.y + v6.x;                    \
+        s5.x = v5.x - v7.y;                    \
+        s5.y = v5.y + v7.x;                    \
+        s6.x = v4.x + v6.y;                    \
+        s6.y = v4.y - v6.x;                    \
+        s7.x = v5.x + v7.y;                    \
+        s7.y = v5.y - v7.x;                    \
+        t0.x = -s3.y;                          \
+        t0.y = s3.x;                           \
+        t1.x = M_SQRT1_2_F * (s5.x - s5.y);    \
+        t1.y = M_SQRT1_2_F * (s5.x + s5.y);    \
+        t2.x = -M_SQRT1_2_F * (s7.x + s7.y);   \
+        t2.y = M_SQRT1_2_F * (s7.x - s7.y);    \
+        c0   = s0 + s1;                        \
+        c1   = s6 - t2;                        \
+        c2   = s2 - t0;                        \
+        c3   = s4 - t1;                        \
+        c4   = s0 - s1;                        \
+        c5   = s6 + t2;                        \
+        c6   = s2 + t0;                        \
+        c7   = s4 + t1;                        \
+    }
+
+/** Computes the first stage of a radix-2 DFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ */
+kernel void fft_radix_2_first_stage_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+)
+{
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT(input);
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT(output);
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float4 data = vload4(0, (__global float *)input.ptr);
+
+    // Compute DFT N = 2
+    DFT_2(data.s01, data.s23);
+
+    // Store eight complex output values
+    vstore4(data, 0, (__global float *)output.ptr);
+}
+
+/** Computes the first stage of a radix-3 DFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ */
+kernel void fft_radix_3_first_stage_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+)
+{
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT(input);
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT(output);
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float4 data0 = vload4(0, (__global float *)input.ptr);
+    float2 data1 = vload2(0, (__global float *)tensor3D_offset(&input, 2, 0, 0));
+
+    // Compute DFT N = 3
+    DFT_3(data0.s01, data0.s23, data1.s01);
+
+    // Store eight complex output values
+    vstore4(data0, 0, (__global float *)output.ptr);
+    vstore2(data1, 0, (__global float *)tensor3D_offset(&output, 2, 0, 0));
+}
+
+/** Computes the first stage of a radix-4 DFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ */
+kernel void fft_radix_4_first_stage_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+)
+{
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT(input);
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT(output);
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float8 data = vload8(0, (__global float *)input.ptr);
+
+    // Compute DFT N = 4
+    DFT_4(data.s01, data.s23, data.s45, data.s67);
+
+    // Store eight complex output values
+    vstore8(data, 0, (__global float *)output.ptr);
+}
+
+/** Computes the first stage of a radix-5 DFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ */
+kernel void fft_radix_5_first_stage_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+)
+{
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT(input);
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT(output);
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float8 data0 = vload8(0, (__global float *)input.ptr);
+    float2 data1 = vload2(0, (__global float *)tensor3D_offset(&input, 4, 0, 0));
+
+    // Compute DFT N = 5
+    DFT_5(data0.s01, data0.s23, data0.s45, data0.s67, data1.s01);
+
+    // Store eight complex output values
+    vstore8(data0, 0, (__global float *)output.ptr);
+    vstore2(data1, 0, (__global float *)tensor3D_offset(&output, 4, 0, 0));
+}
+
+/** Computes the first stage of a radix-7 DFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ */
+kernel void fft_radix_7_first_stage_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+)
+{
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT(input);
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT(output);
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float8 data0 = vload8(0, (__global float *)input.ptr);
+    float4 data1 = vload4(0, (__global float *)tensor3D_offset(&input, 4, 0, 0));
+    float2 data2 = vload2(0, (__global float *)tensor3D_offset(&input, 6, 0, 0));
+
+    // Compute DFT N = 7
+    DFT_7(data0.s01, data0.s23, data0.s45, data0.s67, data1.s01, data1.s23, data2.s01);
+
+    // Store eight complex output values
+    vstore8(data0, 0, (__global float *)output.ptr);
+    vstore4(data1, 0, (__global float *)tensor3D_offset(&output, 4, 0, 0));
+    vstore2(data2, 0, (__global float *)tensor3D_offset(&output, 6, 0, 0));
+}
+
+/** Computes the first stage of a radix-8 DFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ */
+kernel void fft_radix_8_first_stage_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+)
+{
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT(input);
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT(output);
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float16 data = vload16(0, (__global float *)input.ptr);
+
+    // Compute DFT N = 8
+    DFT_8(data.s01, data.s23, data.s45, data.s67, data.s89, data.sAB, data.sCD, data.sEF);
+
+    // Store eight complex output values
+    vstore16(data, 0, (__global float *)output.ptr);
+}
+
+/** Computes a stage of a radix-2 FFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ * @param[in]     Nx                                   The butterfly span. Products of radix order of previous radix's stage
+ * @param[in]     Ni                                   Nx * Ny.
+ * @param[in]     exp_const                            Exponent constant
+ */
+kernel void fft_radix_2_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+    ,
+    uint Nx, uint Ni, float exp_const)
+{
+    // Each work-item computes a single radix-2
+    uint kx = get_global_id(0);
+
+    // Compute nx
+    uint nx = kx % Nx;
+
+    // Compute n index
+    uint n = nx + (kx / Nx) * Ni;
+
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(input);
+    input.ptr += n * input.stride_x + get_global_id(1) * input.stride_y + get_global_id(2) * input.stride_z;
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(output);
+    output.ptr += n * output.stride_x + get_global_id(1) * output.stride_y + get_global_id(2) * output.stride_z;
+#endif /* IN_PLACE */
+
+    // Load two complex input values
+    float2 c0 = vload2(0, (__global float *)input.ptr);
+    float2 c1 = vload2(0, (__global float *)tensor3D_offset(&input, Nx, 0, 0));
+
+    // Compute phi
+    float phi = (float)nx * exp_const;
+
+    // Multiply by twiddle factor
+    TWIDDLE_FACTOR_MULTIPLICATION(phi, c1);
+
+    // Compute DFT N = 2
+    DFT_2(c0, c1);
+
+    // Store two complex output values
+    vstore2(c0, 0, (__global float *)output.ptr);
+    vstore2(c1, 0, (__global float *)tensor3D_offset(&output, Nx, 0, 0));
+}
+
+/** Computes a stage of a radix-3 FFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ * @param[in]     Nx                                   The butterfly span. Products of radix order of previous radix's stage
+ * @param[in]     Ni                                   Nx * Ny.
+ * @param[in]     exp_const                            Exponent constant
+ */
+kernel void fft_radix_3_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+    ,
+    uint Nx, uint Ni, float exp_const)
+{
+    // Each work-item computes a single radix-3
+    uint kx = get_global_id(0);
+
+    // Compute nx
+    uint nx = kx % Nx;
+
+    // Compute n index
+    uint n = nx + (kx / Nx) * Ni;
+
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(input);
+    input.ptr += n * input.stride_x + get_global_id(1) * input.stride_y + get_global_id(2) * input.stride_z;
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(output);
+    output.ptr += n * output.stride_x + get_global_id(1) * output.stride_y + get_global_id(2) * output.stride_z;
+#endif /* IN_PLACE */
+
+    // Load three complex input values
+    float2 c0 = vload2(0, (__global float *)input.ptr);
+    float2 c1 = vload2(0, (__global float *)tensor3D_offset(&input, Nx, 0, 0));
+    float2 c2 = vload2(0, (__global float *)tensor3D_offset(&input, 2 * Nx, 0, 0));
+
+    // Compute phi
+    float phi = (float)nx * exp_const;
+
+    // Multiply by twiddle factor
+    TWIDDLE_FACTOR_MULTIPLICATION(phi, c1);
+    TWIDDLE_FACTOR_MULTIPLICATION(2 * phi, c2);
+
+    // Compute DFT N = 3
+    DFT_3(c0, c1, c2);
+
+    // Store three complex output values
+    vstore2(c0, 0, (__global float *)output.ptr);
+    vstore2(c1, 0, (__global float *)tensor3D_offset(&output, Nx, 0, 0));
+    vstore2(c2, 0, (__global float *)tensor3D_offset(&output, 2 * Nx, 0, 0));
+}
+
+/** Computes a stage of a radix-4 FFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ * @param[in]     Nx                                   The butterfly span. Products of radix order of previous radix's stage
+ * @param[in]     Ni                                   Nx * Ny.
+ * @param[in]     exp_const                            Exponent constant
+ */
+kernel void fft_radix_4_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+    ,
+    uint Nx, uint Ni, float exp_const)
+{
+    // Each work-item computes a single radix-4
+    uint kx = get_global_id(0);
+
+    // Compute nx
+    uint nx = kx % Nx;
+
+    // Compute n index
+    uint n = nx + (kx / Nx) * Ni;
+
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(input);
+    input.ptr += n * input.stride_x + get_global_id(1) * input.stride_y + get_global_id(2) * input.stride_z;
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(output);
+    output.ptr += n * output.stride_x + get_global_id(1) * output.stride_y + get_global_id(2) * output.stride_z;
+#endif /* IN_PLACE */
+
+    // Load four complex input values
+    float2 c0 = vload2(0, (__global float *)input.ptr);
+    float2 c1 = vload2(0, (__global float *)tensor3D_offset(&input, Nx, 0, 0));
+    float2 c2 = vload2(0, (__global float *)tensor3D_offset(&input, 2 * Nx, 0, 0));
+    float2 c3 = vload2(0, (__global float *)tensor3D_offset(&input, 3 * Nx, 0, 0));
+
+    // Compute phi
+    float phi = (float)nx * exp_const;
+
+    // Multiply by twiddle factor
+    TWIDDLE_FACTOR_MULTIPLICATION(phi, c1);
+    TWIDDLE_FACTOR_MULTIPLICATION(2 * phi, c2);
+    TWIDDLE_FACTOR_MULTIPLICATION(3 * phi, c3);
+
+    // Compute DFT N = 4
+    DFT_4(c0, c1, c2, c3);
+
+    // Store four complex output values
+    vstore2(c0, 0, (__global float *)output.ptr);
+    vstore2(c1, 0, (__global float *)tensor3D_offset(&output, Nx, 0, 0));
+    vstore2(c2, 0, (__global float *)tensor3D_offset(&output, 2 * Nx, 0, 0));
+    vstore2(c3, 0, (__global float *)tensor3D_offset(&output, 3 * Nx, 0, 0));
+}
+
+/** Computes a stage of a radix-5 FFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ * @param[in]     Nx                                   The butterfly span. Products of radix order of previous radix's stage
+ * @param[in]     Ni                                   Nx * Ny.
+ * @param[in]     exp_const                            Exponent constant
+ */
+kernel void fft_radix_5_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+    ,
+    uint Nx, uint Ni, float exp_const)
+{
+    // Each work-item computes a single radix-5
+    uint kx = get_global_id(0);
+
+    // Compute nx
+    uint nx = kx % Nx;
+
+    // Compute n index
+    uint n = nx + (kx / Nx) * Ni;
+
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(input);
+    input.ptr += n * input.stride_x + get_global_id(1) * input.stride_y + get_global_id(2) * input.stride_z;
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(output);
+    output.ptr += n * output.stride_x + get_global_id(1) * output.stride_y + get_global_id(2) * output.stride_z;
+#endif /* IN_PLACE */
+
+    // Load five complex input values
+    float2 c0 = vload2(0, (__global float *)input.ptr);
+    float2 c1 = vload2(0, (__global float *)tensor3D_offset(&input, Nx, 0, 0));
+    float2 c2 = vload2(0, (__global float *)tensor3D_offset(&input, 2 * Nx, 0, 0));
+    float2 c3 = vload2(0, (__global float *)tensor3D_offset(&input, 3 * Nx, 0, 0));
+    float2 c4 = vload2(0, (__global float *)tensor3D_offset(&input, 4 * Nx, 0, 0));
+
+    // Compute phi
+    float phi = (float)nx * exp_const;
+
+    // Multiply by twiddle factor
+    TWIDDLE_FACTOR_MULTIPLICATION(phi, c1);
+    TWIDDLE_FACTOR_MULTIPLICATION(2 * phi, c2);
+    TWIDDLE_FACTOR_MULTIPLICATION(3 * phi, c3);
+    TWIDDLE_FACTOR_MULTIPLICATION(4 * phi, c4);
+
+    // Compute DFT N = 5
+    DFT_5(c0, c1, c2, c3, c4);
+
+    // Store five complex output values
+    vstore2(c0, 0, (__global float *)output.ptr);
+    vstore2(c1, 0, (__global float *)tensor3D_offset(&output, Nx, 0, 0));
+    vstore2(c2, 0, (__global float *)tensor3D_offset(&output, 2 * Nx, 0, 0));
+    vstore2(c3, 0, (__global float *)tensor3D_offset(&output, 3 * Nx, 0, 0));
+    vstore2(c4, 0, (__global float *)tensor3D_offset(&output, 4 * Nx, 0, 0));
+}
+
+/** Computes a stage of a radix-7 FFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ * @param[in]     Nx                                   The butterfly span. Products of radix order of previous radix's stage
+ * @param[in]     Ni                                   Nx * Ny.
+ * @param[in]     exp_const                            Exponent constant
+ */
+kernel void fft_radix_7_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+    ,
+    uint Nx, uint Ni, float exp_const)
+{
+    // Each work-item computes a single radix-7
+    uint kx = get_global_id(0);
+
+    // Compute nx
+    uint nx = kx % Nx;
+
+    // Compute n index
+    uint n = nx + (kx / Nx) * Ni;
+
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(input);
+    input.ptr += n * input.stride_x + get_global_id(1) * input.stride_y + get_global_id(2) * input.stride_z;
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(output);
+    output.ptr += n * output.stride_x + get_global_id(1) * output.stride_y + get_global_id(2) * output.stride_z;
+#endif /* IN_PLACE */
+
+    // Load seven complex input values
+    float2 c0 = vload2(0, (__global float *)input.ptr);
+    float2 c1 = vload2(0, (__global float *)tensor3D_offset(&input, Nx, 0, 0));
+    float2 c2 = vload2(0, (__global float *)tensor3D_offset(&input, 2 * Nx, 0, 0));
+    float2 c3 = vload2(0, (__global float *)tensor3D_offset(&input, 3 * Nx, 0, 0));
+    float2 c4 = vload2(0, (__global float *)tensor3D_offset(&input, 4 * Nx, 0, 0));
+    float2 c5 = vload2(0, (__global float *)tensor3D_offset(&input, 5 * Nx, 0, 0));
+    float2 c6 = vload2(0, (__global float *)tensor3D_offset(&input, 6 * Nx, 0, 0));
+
+    // Compute phi
+    float phi = (float)nx * exp_const;
+
+    // Multiply by twiddle factor
+    TWIDDLE_FACTOR_MULTIPLICATION(phi, c1);
+    TWIDDLE_FACTOR_MULTIPLICATION(2 * phi, c2);
+    TWIDDLE_FACTOR_MULTIPLICATION(3 * phi, c3);
+    TWIDDLE_FACTOR_MULTIPLICATION(4 * phi, c4);
+    TWIDDLE_FACTOR_MULTIPLICATION(5 * phi, c5);
+    TWIDDLE_FACTOR_MULTIPLICATION(6 * phi, c6);
+
+    // Compute DFT N = 7
+    DFT_7(c0, c1, c2, c3, c4, c5, c6);
+
+    // Store seven complex output values
+    vstore2(c0, 0, (__global float *)output.ptr);
+    vstore2(c1, 0, (__global float *)tensor3D_offset(&output, Nx, 0, 0));
+    vstore2(c2, 0, (__global float *)tensor3D_offset(&output, 2 * Nx, 0, 0));
+    vstore2(c3, 0, (__global float *)tensor3D_offset(&output, 3 * Nx, 0, 0));
+    vstore2(c4, 0, (__global float *)tensor3D_offset(&output, 4 * Nx, 0, 0));
+    vstore2(c5, 0, (__global float *)tensor3D_offset(&output, 5 * Nx, 0, 0));
+    vstore2(c6, 0, (__global float *)tensor3D_offset(&output, 6 * Nx, 0, 0));
+}
+
+/** Computes a stage of a radix-8 FFT.
+ *
+ * @note In order to perform the FFT function "in-place", the pre-processor -DIN_PLACE must be passed at compile time
+ *
+ * @param[in,out] input_ptr                            Pointer to the source tensor. Supported data types: F32
+ * @param[in,out] input_stride_x                       Stride of the source tensor in X dimension (in bytes)
+ * @param[in,out] input_step_x                         input_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in,out] input_stride_y                       Stride of the source tensor in Y dimension (in bytes)
+ * @param[in,out] input_step_y                         input_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in,out] input_stride_z                       Stride of the source tensor in Z dimension (in bytes)
+ * @param[in,out] input_step_z                         input_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in,out] input_offset_first_element_in_bytes  The offset of the first element in the source tensor
+ * @param[out]    output_ptr                           Pointer to the destination image. Supported data types: same as @p input_ptr
+ * @param[in]     output_stride_x                      Stride of the destination image in X dimension (in bytes)
+ * @param[in]     output_step_x                        output_stride_x * number of elements along X processed per workitem(in bytes)
+ * @param[in]     output_stride_y                      Stride of the destination image in Y dimension (in bytes)
+ * @param[in]     output_step_y                        output_stride_y * number of elements along Y processed per workitem(in bytes)
+ * @param[in]     output_stride_z                      Stride of the source tensor in Z dimension (in bytes)
+ * @param[in]     output_step_z                        output_stride_z * number of elements along Z processed per workitem(in bytes)
+ * @param[in]     output_offset_first_element_in_bytes The offset of the first element in the destination image
+ * @param[in]     Nx                                   The butterfly span. Products of radix order of previous radix's stage
+ * @param[in]     Ni                                   Nx * Ny.
+ * @param[in]     exp_const                            Exponent constant
+ */
+kernel void fft_radix_8_axis_0(
+    TENSOR3D_DECLARATION(input)
+#ifndef IN_PLACE
+    ,
+    TENSOR3D_DECLARATION(output)
+#endif /* not IN_PLACE */
+    ,
+    uint Nx, uint Ni, float exp_const)
+{
+    // Each work-item computes a single radix-8
+    uint kx = get_global_id(0);
+
+    // Compute nx
+    uint nx = kx % Nx;
+
+    // Compute n index
+    uint n = nx + (kx / Nx) * Ni;
+
+    // Get tensor pointers
+    Tensor3D input = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(input);
+    input.ptr += n * input.stride_x + get_global_id(1) * input.stride_y + get_global_id(2) * input.stride_z;
+#ifdef IN_PLACE
+    Tensor3D output = input;
+#else  /* IN_PLACE */
+    Tensor3D output = CONVERT_TO_TENSOR3D_STRUCT_NO_STEP(output);
+    output.ptr += n * output.stride_x + get_global_id(1) * output.stride_y + get_global_id(2) * output.stride_z;
+#endif /* IN_PLACE */
+
+    // Load eight complex input values
+    float2 c0 = vload2(0, (__global float *)input.ptr);
+    float2 c1 = vload2(0, (__global float *)tensor3D_offset(&input, Nx, 0, 0));
+    float2 c2 = vload2(0, (__global float *)tensor3D_offset(&input, 2 * Nx, 0, 0));
+    float2 c3 = vload2(0, (__global float *)tensor3D_offset(&input, 3 * Nx, 0, 0));
+    float2 c4 = vload2(0, (__global float *)tensor3D_offset(&input, 4 * Nx, 0, 0));
+    float2 c5 = vload2(0, (__global float *)tensor3D_offset(&input, 5 * Nx, 0, 0));
+    float2 c6 = vload2(0, (__global float *)tensor3D_offset(&input, 6 * Nx, 0, 0));
+    float2 c7 = vload2(0, (__global float *)tensor3D_offset(&input, 7 * Nx, 0, 0));
+
+    // Compute phi
+    float phi = (float)nx * exp_const;
+
+    // Multiply by twiddle factor
+    TWIDDLE_FACTOR_MULTIPLICATION(phi, c1);
+    TWIDDLE_FACTOR_MULTIPLICATION(2 * phi, c2);
+    TWIDDLE_FACTOR_MULTIPLICATION(3 * phi, c3);
+    TWIDDLE_FACTOR_MULTIPLICATION(4 * phi, c4);
+    TWIDDLE_FACTOR_MULTIPLICATION(5 * phi, c5);
+    TWIDDLE_FACTOR_MULTIPLICATION(6 * phi, c6);
+    TWIDDLE_FACTOR_MULTIPLICATION(7 * phi, c7);
+
+    // Compute DFT N = 8
+    DFT_8(c0, c1, c2, c3, c4, c5, c6, c7);
+
+    // Store eight complex output values
+    vstore2(c0, 0, (__global float *)output.ptr);
+    vstore2(c1, 0, (__global float *)tensor3D_offset(&output, Nx, 0, 0));
+    vstore2(c2, 0, (__global float *)tensor3D_offset(&output, 2 * Nx, 0, 0));
+    vstore2(c3, 0, (__global float *)tensor3D_offset(&output, 3 * Nx, 0, 0));
+    vstore2(c4, 0, (__global float *)tensor3D_offset(&output, 4 * Nx, 0, 0));
+    vstore2(c5, 0, (__global float *)tensor3D_offset(&output, 5 * Nx, 0, 0));
+    vstore2(c6, 0, (__global float *)tensor3D_offset(&output, 6 * Nx, 0, 0));
+    vstore2(c7, 0, (__global float *)tensor3D_offset(&output, 7 * Nx, 0, 0));
+}
\ No newline at end of file
diff --git a/src/core/CL/kernels/CLFFTDigitReverseKernel.cpp b/src/core/CL/kernels/CLFFTDigitReverseKernel.cpp
new file mode 100644
index 0000000000..d72647c3c9
--- /dev/null
+++ b/src/core/CL/kernels/CLFFTDigitReverseKernel.cpp
@@ -0,0 +1,124 @@
+/*
+ * 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.
+ */
+#include "arm_compute/core/CL/kernels/CLFFTDigitReverseKernel.h"
+
+#include "arm_compute/core/CL/CLKernelLibrary.h"
+#include "arm_compute/core/CL/CLValidate.h"
+#include "arm_compute/core/CL/ICLTensor.h"
+#include "arm_compute/core/TensorInfo.h"
+#include "arm_compute/core/Types.h"
+#include "arm_compute/core/Window.h"
+
+namespace arm_compute
+{
+namespace
+{
+Status validate_arguments(const ITensorInfo *input, const ITensorInfo *output, const ITensorInfo *idx, unsigned int axis)
+{
+    ARM_COMPUTE_RETURN_ERROR_ON_F16_UNSUPPORTED(input);
+    ARM_COMPUTE_RETURN_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input, 2, DataType::F32);
+    ARM_COMPUTE_RETURN_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(idx, 1, DataType::U32);
+    ARM_COMPUTE_RETURN_ERROR_ON(axis != 0);
+
+    // Checks performed when output is configured
+    if((output != nullptr) && (output->total_size() != 0))
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_SHAPES(input, output);
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_TYPES(input, output);
+    }
+
+    return Status{};
+}
+
+std::pair<Status, Window> validate_and_configure_window(ITensorInfo *input, ITensorInfo *output, ITensorInfo *idx, unsigned int axis)
+{
+    ARM_COMPUTE_UNUSED(idx, axis);
+
+    auto_init_if_empty(*output, *input);
+
+    Window win = calculate_max_window(*output, Steps());
+    output->set_valid_region(ValidRegion(Coordinates(), output->tensor_shape()));
+
+    return std::make_pair(Status{}, win);
+}
+} // namespace
+
+CLFFTDigitReverseKernel::CLFFTDigitReverseKernel()
+    : _input(nullptr), _output(nullptr), _idx(nullptr)
+{
+}
+
+void CLFFTDigitReverseKernel::configure(const ICLTensor *input, ICLTensor *output, const ICLTensor *idx, unsigned int axis)
+{
+    ARM_COMPUTE_ERROR_ON_NULLPTR(input, output, idx);
+    ARM_COMPUTE_ERROR_THROW_ON(validate_arguments(input->info(), output->info(), idx->info(), axis));
+
+    _input  = input;
+    _output = output;
+    _idx    = idx;
+
+    // Create kernel
+    _kernel = static_cast<cl::Kernel>(CLKernelLibrary::get().create_kernel("digit_reverse"));
+
+    // Configure kernel window
+    auto win_config = validate_and_configure_window(input->info(), output->info(), idx->info(), axis);
+    ARM_COMPUTE_ERROR_THROW_ON(win_config.first);
+    ICLKernel::configure_internal(win_config.second);
+
+    // Set config_id for enabling LWS tuning
+    _config_id = "digit_reverse_";
+    _config_id += lower_string(string_from_data_type(input->info()->data_type()));
+    _config_id += "_";
+    _config_id += support::cpp11::to_string(input->info()->dimension(0));
+    _config_id += "_";
+    _config_id += support::cpp11::to_string(input->info()->dimension(1));
+}
+
+Status CLFFTDigitReverseKernel::validate(const ITensorInfo *input, const ITensorInfo *output, const ITensorInfo *idx, unsigned int axis)
+{
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_arguments(input, output, idx, axis));
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_and_configure_window(input->clone().get(), output->clone().get(), idx->clone().get(), axis).first);
+
+    return Status{};
+}
+
+void CLFFTDigitReverseKernel::run(const Window &window, cl::CommandQueue &queue)
+{
+    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
+    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(ICLKernel::window(), window);
+
+    Window collapsed = window.collapse_if_possible(ICLKernel::window(), Window::DimZ);
+    Window slice     = collapsed.first_slice_window_3D();
+
+    do
+    {
+        unsigned int idx = 0;
+        add_3D_tensor_argument(idx, _input, slice);
+        add_3D_tensor_argument(idx, _output, slice);
+        add_1D_tensor_argument(idx, _idx, slice);
+        enqueue(queue, *this, slice, lws_hint());
+    }
+    while(collapsed.slide_window_slice_3D(slice));
+}
+} // namespace arm_compute
diff --git a/src/core/CL/kernels/CLFFTRadixStageKernel.cpp b/src/core/CL/kernels/CLFFTRadixStageKernel.cpp
new file mode 100644
index 0000000000..87a12b9da9
--- /dev/null
+++ b/src/core/CL/kernels/CLFFTRadixStageKernel.cpp
@@ -0,0 +1,163 @@
+/*
+ * 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.
+ */
+#include "arm_compute/core/CL/kernels/CLFFTRadixStageKernel.h"
+
+#include "arm_compute/core/CL/CLHelpers.h"
+#include "arm_compute/core/CL/CLKernelLibrary.h"
+#include "arm_compute/core/CL/CLValidate.h"
+#include "arm_compute/core/CL/ICLTensor.h"
+#include "arm_compute/core/TensorInfo.h"
+#include "arm_compute/core/Types.h"
+#include "arm_compute/core/Utils.h"
+#include "arm_compute/core/Window.h"
+
+#include <cmath>
+
+namespace arm_compute
+{
+namespace
+{
+Status validate_arguments(const ITensorInfo *input, const ITensorInfo *output, const FFTRadixStageKernelDescriptor &config)
+{
+    ARM_COMPUTE_RETURN_ERROR_ON_F16_UNSUPPORTED(input);
+    ARM_COMPUTE_RETURN_ERROR_ON_DATA_TYPE_CHANNEL_NOT_IN(input, 2, DataType::F32);
+    ARM_COMPUTE_RETURN_ERROR_ON(config.axis != 0);
+    ARM_COMPUTE_RETURN_ERROR_ON(CLFFTRadixStageKernel::supported_radix().count(config.radix) == 0);
+
+    // Checks performed when output is configured
+    if((output != nullptr) && (output->total_size() != 0))
+    {
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_SHAPES(input, output);
+        ARM_COMPUTE_RETURN_ERROR_ON_MISMATCHING_DATA_TYPES(input, output);
+    }
+
+    return Status{};
+}
+
+std::pair<Status, Window> validate_and_configure_window(ITensorInfo *input, ITensorInfo *output, const FFTRadixStageKernelDescriptor &config)
+{
+    if(output != nullptr)
+    {
+        auto_init_if_empty(*output, *input);
+    }
+
+    Window win = calculate_max_window(*input, Steps(config.radix));
+    if(output != nullptr)
+    {
+        output->set_valid_region(ValidRegion(Coordinates(), output->tensor_shape()));
+    }
+
+    return std::make_pair(Status{}, win);
+}
+} // namespace
+
+CLFFTRadixStageKernel::CLFFTRadixStageKernel()
+    : _input(nullptr), _output(nullptr), _run_in_place(false)
+{
+}
+
+void CLFFTRadixStageKernel::configure(ICLTensor *input, ICLTensor *output, const FFTRadixStageKernelDescriptor &config)
+{
+    ARM_COMPUTE_ERROR_ON_NULLPTR(input);
+    ARM_COMPUTE_ERROR_THROW_ON(validate_arguments(input->info(), (output != nullptr) ? output->info() : nullptr, config));
+
+    _input        = input;
+    _output       = output;
+    _run_in_place = (output == nullptr) || (output == input);
+
+    // Create build options
+    CLBuildOptions build_opts;
+    build_opts.add_option_if(_run_in_place, "-DIN_PLACE");
+
+    // Create kernel
+    std::string kernel_name = "fft";
+    kernel_name += "_radix_" + support::cpp11::to_string(config.radix);
+    kernel_name += (config.is_first_stage) ? "_first_stage" : "";
+    kernel_name += "_axis_" + support::cpp11::to_string(config.axis);
+    _kernel = static_cast<cl::Kernel>(CLKernelLibrary::get().create_kernel(kernel_name, build_opts.options()));
+
+    // Set static arguments if not the first stage
+    if(!config.is_first_stage)
+    {
+        const unsigned int Ni        = config.Nx * config.radix;
+        const float        exp_const = (-2.0 * M_PI) / static_cast<float>(Ni);
+        unsigned int       idx       = (1 + (_run_in_place ? 0 : 1)) * num_arguments_per_3D_tensor(); // Skip the input and output parameters
+        _kernel.setArg<cl_uint>(idx++, config.Nx);
+        _kernel.setArg<cl_uint>(idx++, Ni);
+        _kernel.setArg<cl_float>(idx++, exp_const);
+    }
+
+    // Configure kernel window
+    auto win_config = validate_and_configure_window(input->info(), (_run_in_place) ? nullptr : output->info(), config);
+    ARM_COMPUTE_ERROR_THROW_ON(win_config.first);
+    ICLKernel::configure_internal(win_config.second);
+
+    // Set config_id for enabling LWS tuning
+    _config_id = kernel_name;
+    _config_id += "_";
+    _config_id += lower_string(string_from_data_type(input->info()->data_type()));
+    _config_id += "_";
+    _config_id += support::cpp11::to_string(input->info()->dimension(0));
+    _config_id += "_";
+    _config_id += support::cpp11::to_string(input->info()->dimension(1));
+}
+
+Status CLFFTRadixStageKernel::validate(const ITensorInfo *input, const ITensorInfo *output, const FFTRadixStageKernelDescriptor &config)
+{
+    const bool run_in_place = (output == nullptr) || (output == input);
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_arguments(input, output, config));
+    ARM_COMPUTE_RETURN_ON_ERROR(validate_and_configure_window(input->clone().get(),
+                                                              (run_in_place) ? nullptr : output->clone().get(),
+                                                              config)
+                                .first);
+
+    return Status{};
+}
+
+std::set<unsigned int> CLFFTRadixStageKernel::supported_radix()
+{
+    return std::set<unsigned int> { 2, 3, 4, 5, 7, 8 };
+}
+
+void CLFFTRadixStageKernel::run(const Window &window, cl::CommandQueue &queue)
+{
+    ARM_COMPUTE_ERROR_ON_UNCONFIGURED_KERNEL(this);
+    ARM_COMPUTE_ERROR_ON_INVALID_SUBWINDOW(ICLKernel::window(), window);
+
+    Window collapsed = window.collapse_if_possible(ICLKernel::window(), Window::DimZ);
+    Window slice     = collapsed.first_slice_window_3D();
+
+    do
+    {
+        unsigned int idx = 0;
+        add_3D_tensor_argument(idx, _input, slice);
+        if(!_run_in_place)
+        {
+            add_3D_tensor_argument(idx, _output, slice);
+        }
+        enqueue(queue, *this, slice, lws_hint());
+    }
+    while(collapsed.slide_window_slice_3D(slice));
+}
+} // namespace arm_compute
diff --git a/src/core/utils/helpers/fft.cpp b/src/core/utils/helpers/fft.cpp
new file mode 100644
index 0000000000..7ff2fdf62b
--- /dev/null
+++ b/src/core/utils/helpers/fft.cpp
@@ -0,0 +1,124 @@
+/*
+ * 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.
+ */
+#include "arm_compute/core/utils/helpers/fft.h"
+
+#include <numeric>
+
+namespace arm_compute
+{
+namespace helpers
+{
+namespace fft
+{
+std::vector<unsigned int> decompose_stages(unsigned int N, const std::set<unsigned int> &supported_factors)
+{
+    std::vector<unsigned int> stages;
+    unsigned int              res = N;
+
+    // Early exit if no supported factors are provided
+    if(supported_factors.empty())
+    {
+        return stages;
+    }
+
+    // Create reverse iterator (Start decomposing from the larger supported factors)
+    auto rfactor_it = supported_factors.rbegin();
+
+    // Decomposition step
+    while(res != 0)
+    {
+        const unsigned int factor = *rfactor_it;
+        if(0 == (res % factor) && res >= factor)
+        {
+            stages.push_back(factor);
+            res /= factor;
+        }
+        else
+        {
+            ++rfactor_it;
+            if(rfactor_it == supported_factors.rend())
+            {
+                if(res > 1)
+                {
+                    // Couldn't decompose with given factors
+                    stages.clear();
+                    return stages;
+                }
+                else
+                {
+                    res = 0;
+                }
+            }
+        }
+    }
+
+    return stages;
+}
+
+std::vector<unsigned int> digit_reverse_indices(unsigned int N, const std::vector<unsigned int> &fft_stages)
+{
+    std::vector<unsigned int> idx_digit_reverse;
+
+    // Early exit in case N and fft stages do not match
+    const float stages_prod = std::accumulate(std::begin(fft_stages), std::end(fft_stages), 1, std::multiplies<unsigned int>());
+    if(stages_prod != N)
+    {
+        return idx_digit_reverse;
+    }
+
+    // Resize digit reverse vector
+    idx_digit_reverse.resize(N);
+
+    // Get number of radix stages
+    unsigned int n_stages = fft_stages.size();
+
+    // Scan elements
+    for(unsigned int n = 0; n < N; ++n)
+    {
+        unsigned int k  = n;
+        unsigned int Nx = fft_stages[0];
+
+        // Scan stages
+        for(unsigned int s = 1; s < n_stages; ++s)
+        {
+            // radix of stage i-th
+            unsigned int Ny = fft_stages[s];
+            unsigned int Ni = Ny * Nx;
+
+            // Update k index
+            k = (k * Ny) % Ni + (k / Nx) % Ny + Ni * (k / Ni);
+
+            // Update Nx
+            Nx *= Ny;
+        }
+
+        // K is the index of digit-reverse
+        idx_digit_reverse[n] = k;
+    }
+
+    return idx_digit_reverse;
+}
+} // namespace fft
+} // namespace helpers
+} // namespace arm_compute