GPUCodeForces/S1/gsd123_#29/ChebyshevDistance_cuda.py

121 lines
3.8 KiB
Python

import torch
import torch.nn as nn
from torch.utils.cpp_extension import load_inline
class ModelNew(nn.Module):
def __init__(self, feature_dim):
super().__init__()
self.register_buffer("center", torch.zeros(feature_dim))
self._compile_cuda_kernel()
def _compile_cuda_kernel(self):
cpp_source = """
#include <torch/extension.h>
torch::Tensor chebyshev_cuda(torch::Tensor x, torch::Tensor center);
"""
cuda_source = """
#include <cuda_runtime.h>
#include <math.h>
__device__ __forceinline__ float warp_reduce_max(float val) {
#pragma unroll
for (int offset = 16; offset > 0; offset /= 2) {
float other = __shfl_down_sync(0xffffffff, val, offset);
val = fmaxf(val, other);
}
return val;
}
__device__ __forceinline__ float block_reduce_max(float val) {
static __shared__ float shared[32];
int lane = threadIdx.x % 32;
int wid = threadIdx.x / 32;
val = warp_reduce_max(val);
if (lane == 0) shared[wid] = val;
__syncthreads();
val = (threadIdx.x < blockDim.x / 32) ? shared[lane] : 0.0f;
if (wid == 0) val = warp_reduce_max(val);
return val;
}
__global__ void chebyshev_kernel_vec4(
const float* __restrict__ x,
const float* __restrict__ center,
float* __restrict__ output,
int batch_size,
int feature_dim)
{
int bid = blockIdx.x;
if (bid >= batch_size) return;
const float* row_x = x + bid * feature_dim;
float max_val = 0.0f;
int vec_loops = feature_dim / 4;
int vec_remainder = feature_dim % 4;
for (int i = threadIdx.x; i < vec_loops; i += blockDim.x) {
float4 vx = reinterpret_cast<const float4*>(row_x)[i];
float4 vc = reinterpret_cast<const float4*>(center)[i];
max_val = fmaxf(max_val, fabsf(vx.x - vc.x));
max_val = fmaxf(max_val, fabsf(vx.y - vc.y));
max_val = fmaxf(max_val, fabsf(vx.z - vc.z));
max_val = fmaxf(max_val, fabsf(vx.w - vc.w));
}
int tail_start = vec_loops * 4;
if (threadIdx.x < vec_remainder) {
int idx = tail_start + threadIdx.x;
max_val = fmaxf(max_val, fabsf(row_x[idx] - center[idx]));
}
max_val = block_reduce_max(max_val);
if (threadIdx.x == 0) {
output[bid] = max_val;
}
}
torch::Tensor chebyshev_cuda(torch::Tensor x, torch::Tensor center) {
auto x_c = x.contiguous();
auto c_c = center.contiguous();
int batch_size = x_c.size(0);
int feature_dim = x_c.size(1);
auto output = torch::empty({batch_size}, x.options());
int threads = 256;
int blocks = batch_size;
chebyshev_kernel_vec4<<<blocks, threads>>>(
x_c.data_ptr<float>(),
c_c.data_ptr<float>(),
output.data_ptr<float>(),
batch_size,
feature_dim
);
return output;
}
"""
self.op = load_inline(
name="chebyshev_opt_v1",
cpp_sources=cpp_source,
cuda_sources=cuda_source,
functions=["chebyshev_cuda"],
extra_cuda_cflags=["-O3"],
verbose=False
)
def forward(self, x):
return self.op.chebyshev_cuda(x, self.center)