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rocm-systems/projects/hip/docs/tools/example_codes/math.hip
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Istvan Kiss 197f73dac9 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
2025-10-29 07:42:06 +01:00

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// 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 <cmath>
#include <iostream>
#include <limits>
#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); \
} \
}
// Simple ULP difference calculator
int64_t ulp_diff(float a, float b)
{
if (a == b)
return 0;
union
{
float f;
int32_t i;
} ua{a}, ub{b};
// For negative values, convert to a positive-based representation
if (ua.i < 0) ua.i = std::numeric_limits<int32_t>::max() - ua.i;
if (ub.i < 0) ub.i = std::numeric_limits<int32_t>::max() - ub.i;
return std::abs((int64_t)ua.i - (int64_t)ub.i);
}
// Test kernel
__global__ void test_sin(float* out, int n)
{
int i = blockIdx.x * blockDim.x + threadIdx.x;
if (i < n)
{
float x = -M_PI + (2.0f * M_PI * i) / (n - 1);
out[i] = sinf(x);
}
}
int main()
{
const int n = 1000000;
const int blocksize = 256;
std::vector<float> outputs(n);
float* d_out;
HIP_CHECK(hipMalloc(&d_out, n * sizeof(float)));
dim3 threads(blocksize);
dim3 blocks((n + blocksize - 1) / blocksize); // Fixed grid calculation
test_sin<<<blocks, threads>>>(d_out, n);
HIP_CHECK(hipPeekAtLastError());
HIP_CHECK(hipMemcpy(outputs.data(), d_out, n * sizeof(float), hipMemcpyDeviceToHost));
// Step 1: Find the maximum absolute error
double max_abs_error = 0.0;
float max_error_output = 0.0;
float max_error_expected = 0.0;
for (int i = 0; i < n; i++)
{
float x = -M_PI + (2.0f * M_PI * i) / (n - 1);
float expected = std::sin(x);
double abs_error = std::abs(outputs[i] - expected);
if (abs_error > max_abs_error)
{
max_abs_error = abs_error;
max_error_output = outputs[i];
max_error_expected = expected;
}
}
// Step 2: Compute ULP difference based on the max absolute error pair
int64_t max_ulp = ulp_diff(max_error_output, max_error_expected);
// Output results
std::cout << "Max Absolute Error: " << max_abs_error << std::endl;
std::cout << "Max ULP Difference: " << max_ulp << std::endl;
std::cout << "Max Error Values -> Got: " << max_error_output
<< ", Expected: " << max_error_expected << std::endl;
HIP_CHECK(hipFree(d_out));
return 0;
}
// [sphinx-end]