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88 lines
2.8 KiB
Text
88 lines
2.8 KiB
Text
/**
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* knapsack.cuh - 0-1 背包问题
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*
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* 继承 ProblemBase，使用 ObjDef 目标注册机制
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*/
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#pragma once
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#include "types.cuh"
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#include "cuda_utils.cuh"
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#include "operators.cuh"
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struct KnapsackProblem : ProblemBase<KnapsackProblem, 1, 32> {
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// 问题数据（d_weights 是物品重量，非目标权重）
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const float* d_weights;
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const float* d_values;
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float capacity;
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int n;
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// ---- 目标计算 ----
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__device__ float calc_total_value(const Sol& sol) const {
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float tv = 0.0f;
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const int* sel = sol.data[0];
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int size = sol.dim2_sizes[0];
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for (int i = 0; i < size; i++)
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if (sel[i]) tv += d_values[i];
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return tv;
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}
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// ---- 目标定义（OBJ_DEFS 与 compute_obj 必须一一对应）----
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static constexpr ObjDef OBJ_DEFS[] = {
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{ObjDir::Maximize, 1.0f, 0.0f}, // case 0: calc_total_value
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};
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__device__ float compute_obj(int idx, const Sol& sol) const {
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switch (idx) {
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case 0: return calc_total_value(sol); // OBJ_DEFS[0]
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default: return 0.0f;
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}
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}
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__device__ float compute_penalty(const Sol& sol) const {
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float tw = 0.0f;
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const int* sel = sol.data[0];
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int size = sol.dim2_sizes[0];
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for (int i = 0; i < size; i++)
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if (sel[i]) tw += d_weights[i];
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float over = tw - capacity;
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return (over > 0.0f) ? over : 0.0f;
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}
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ProblemConfig config() const {
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ProblemConfig cfg;
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cfg.encoding = EncodingType::Binary;
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cfg.dim1 = 1; cfg.dim2_default = n;
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fill_obj_config(cfg);
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return cfg;
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}
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// ---- shared memory 接口 ----
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size_t shared_mem_bytes() const {
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return 2 * (size_t)n * sizeof(float);
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}
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__device__ void load_shared(char* smem, int tid, int bsz) {
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float* sw = reinterpret_cast<float*>(smem);
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float* sv = sw + n;
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for (int i = tid; i < n; i += bsz) { sw[i] = d_weights[i]; sv[i] = d_values[i]; }
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d_weights = sw;
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d_values = sv;
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}
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static KnapsackProblem create(const float* hw, const float* hv, int n, float cap) {
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KnapsackProblem prob;
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prob.n = n; prob.capacity = cap;
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float *dw, *dv;
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CUDA_CHECK(cudaMalloc(&dw, sizeof(float)*n));
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CUDA_CHECK(cudaMalloc(&dv, sizeof(float)*n));
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CUDA_CHECK(cudaMemcpy(dw, hw, sizeof(float)*n, cudaMemcpyHostToDevice));
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CUDA_CHECK(cudaMemcpy(dv, hv, sizeof(float)*n, cudaMemcpyHostToDevice));
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prob.d_weights = dw; prob.d_values = dv;
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return prob;
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}
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void destroy() {
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if (d_weights) cudaFree(const_cast<float*>(d_weights));
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if (d_values) cudaFree(const_cast<float*>(d_values));
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d_weights = nullptr; d_values = nullptr;
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}
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};
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