Sync HIP documentation 2025-10-20 (#1258)

* Add examples to tools folder
* Correct P2P memory access section
* Sync poriting guide
* Add HIP Graph tutorial
* Add hint about using amdgpu-dkms for IPC API
* Add a few more env variables

projects/hip/docs/tools/example_codes/complex_math.hip

@@ -0,0 +1,142 @@
+// MIT License
+//
+// Copyright (c) 2025 Advanced Micro Devices, Inc. All rights reserved.
+//
+// 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.
+// [sphinx-start]
+#include <hip/hip_runtime.h>
+#include <hip/hip_complex.h>
+
+#include <cmath>
+#include <cstdlib>
+#include <iostream>
+#include <vector>
+
+#define HIP_CHECK(expression)                      \
+    {                                              \
+        const hipError_t err = expression;         \
+        if (err != hipSuccess) {                   \
+            std::cerr << "HIP error: "             \
+                    << hipGetErrorString(err)      \
+                    << " at " << __LINE__ << "\n"; \
+            exit(EXIT_FAILURE);                    \
+        }                                          \
+    }
+
+// Kernel to compute DFT
+__global__ void computeDFT(const float* input, hipFloatComplex* output, const int N)
+{
+    int k = blockIdx.x * blockDim.x + threadIdx.x;
+    if (k >= N) return;
+
+    hipFloatComplex sum = make_hipFloatComplex(0.0f, 0.0f);
+
+    for (int n = 0; n < N; n++)
+    {
+        float angle = -2.0f * M_PI * k * n / N;
+        hipFloatComplex w = make_hipFloatComplex(cosf(angle), sinf(angle));
+        hipFloatComplex x = make_hipFloatComplex(input[n], 0.0f);
+        sum = hipCaddf(sum, hipCmulf(x, w));
+    }
+
+    output[k] = sum;
+}
+
+// CPU implementation of DFT for verification
+std::vector<hipFloatComplex> cpuDFT(const std::vector<float>& input)
+{
+    const int N = input.size();
+    std::vector<hipFloatComplex> result(N);
+
+    for (int k = 0; k < N; k++)
+    {
+        hipFloatComplex sum = make_hipFloatComplex(0.0f, 0.0f);
+        for (int n = 0; n < N; n++)
+        {
+            float angle = -2.0f * M_PI * k * n / N;
+            hipFloatComplex w = make_hipFloatComplex(cosf(angle), sinf(angle));
+            hipFloatComplex x = make_hipFloatComplex(input[n], 0.0f);
+            sum = hipCaddf(sum, hipCmulf(x, w));
+        }
+        result[k] = sum;
+    }
+    return result;
+}
+
+int main()
+{
+    const int N = 256;  // Signal length
+    const int blockSize = 256;
+
+    // Generate input signal: sum of two sine waves
+    std::vector<float> signal(N);
+    for (int i = 0; i < N; i++)
+    {
+        float t = static_cast<float>(i) / N;
+        signal[i] = sinf(2.0f * M_PI * 10.0f * t) +  // 10 Hz component
+                0.5f * sinf(2.0f * M_PI * 20.0f * t);  // 20 Hz component
+    }
+
+    // Compute reference solution on CPU
+    std::vector<hipFloatComplex> cpu_output = cpuDFT(signal);
+
+    // Allocate device memory
+    float* d_signal;
+    hipFloatComplex* d_output;
+    HIP_CHECK(hipMalloc(&d_signal, N * sizeof(float)));
+    HIP_CHECK(hipMalloc(&d_output, N * sizeof(hipFloatComplex)));
+
+    // Copy input to device
+    HIP_CHECK(hipMemcpy(d_signal, signal.data(), N * sizeof(float), hipMemcpyHostToDevice));
+
+    // Launch kernel
+    dim3 grid((N + blockSize - 1) / blockSize);
+    dim3 block(blockSize);
+    computeDFT<<<grid, block>>>(d_signal, d_output, N);
+    HIP_CHECK(hipGetLastError());
+
+    // Get GPU results
+    std::vector<hipFloatComplex> gpu_output(N);
+    HIP_CHECK(hipMemcpy(gpu_output.data(), d_output, N * sizeof(hipFloatComplex), hipMemcpyDeviceToHost));
+
+    // Verify results
+    bool passed = true;
+    const float tolerance = 1e-5f;  // Adjust based on precision requirements
+
+    for (int i = 0; i < N; i++)
+    {
+        float diff_real = std::abs(hipCrealf(gpu_output[i]) - hipCrealf(cpu_output[i]));
+        float diff_imag = std::abs(hipCimagf(gpu_output[i]) - hipCimagf(cpu_output[i]));
+
+        if (diff_real > tolerance || diff_imag > tolerance)
+        {
+            passed = false;
+            break;
+        }
+    }
+
+    std::cout << "DFT Verification: " << (passed ? "PASSED" : "FAILED") << "\n";
+
+    // Cleanup
+    HIP_CHECK(hipFree(d_signal));
+    HIP_CHECK(hipFree(d_output));
+
+    return passed ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+// [sphinx-end]