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dynamics/engines/cpp/main.cpp
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admin e40393d793 fix: display.txt 缺少渲染参数导致盒子不透明 
外部引擎（C/C++）直接写 display.txt 时只输出基础物理参数
（DT/NSTEP/method 等），缺少 alpha/ball_color/box_color
等渲染参数，draw.py 读取不到 alpha 回退默认 0.2。

修复：
1. param.json 新增渲染参数（alpha/ball_color/box_color/...）
2. C/C++ 引擎 SimParams 新增对应字段 & JSON 读取
3. C/C++ write_display_txt 写入所有渲染参数 header
4. param.json ball_color/box_color 用数组统一存储
2026-06-12 15:05:46 +08:00

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/**
* engines/cpp/main.cpp
* --------------------
* C++ 动力学模拟引擎。
* 与 Python 版 (compute.py) 算法保持一致。
*
* 输入: param.json, <input_dir>/coord.txt, connection.txt, bond.txt
* 输出: <output_dir>/trajectory.txt (JSON, 与 Python 版兼容)
*
* 编译:
* g++ -O3 -march=native -std=c++17 -o build/dynamics_cpp main.cpp
*
* 用法:
* ./build/dynamics_cpp <input_dir> <output_dir> <param_json>
*/
#include <algorithm>
#include <chrono>
#include <cmath>
#include <cstring>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
// ========================================================================
// 配置参数（从 param.json 读取）
// ========================================================================
struct SimParams {
double box_a = 10.0;
int NT = 10000;
double DT = 0.001;
int NSTEP = 100;
int warmup_steps = 0;
std::string method = "leapfrog";
double G[3] = {0, 0, -9.8};
double B[3] = {0, 0, 0};
int gravity_field = 1;
int gravity_interaction = 0;
int elastic_force = 1;
int damping_force = 0;
double gravity_strength = 1.0;
int driving_force = 0;
int save_trajectory = 1;
double alpha[6] = {0,0,0,0,0,0};
double ball_radius = 0.5;
double ball_color[3] = {0.9, 0.2, 0.2};
double box_color[3] = {0.8, 0.8, 0.85};
int use_marker = 0;
double camera_distance = 40.0;
double camera_elevation = 0;
double camera_azimuth = 0;
};
// ========================================================================
// 原子数据
// ========================================================================
struct AtomData {
std::vector<int> ids;
std::vector<double> masses;
std::vector<double> radii;
std::vector<double> pos_0; // (n_atoms * 3)
std::vector<double> vel_0; // (n_atoms * 3)
std::vector<int> fixed; // (n_atoms * 3), 0/1 flags
};
// ========================================================================
// 成键数据
// ========================================================================
struct BondData {
std::vector<int> pairs; // (n_bonds * 2)
std::vector<double> stiffness;
std::vector<double> rest_lengths;
};
// ========================================================================
// 驱动力数据
// ========================================================================
struct DriverData {
int n_drivers = 0;
std::vector<int> atom_idx; // internal atom indices
std::vector<double> amp_x, amp_y, amp_z;
std::vector<double> freq_x, freq_y, freq_z;
std::vector<double> phi_x, phi_y, phi_z; // radians
std::vector<int> has_period; // 0=all, 1=limited
std::vector<double> period_cycles;
std::vector<double> freeze_x, freeze_y, freeze_z;
};
// ========================================================================
// 辅助函数
// ========================================================================
static void die(const std::string &msg) {
std::cerr << "[C++-engine] 错误: " << msg << std::endl;
exit(1);
}
/* 读整个文件为字符串 */
static std::string read_file(const std::string &path) {
std::ifstream f(path, std::ios::binary);
if (!f) die("无法打开 " + path);
std::ostringstream ss;
ss << f.rdbuf();
return ss.str();
}
/* 从 JSON 中查找 key，返回冒号后的数值 */
static double json_read_double(const std::string &json, const std::string &key) {
auto pos = json.find("\"" + key + "\"");
if (pos == std::string::npos) return 0.0;
pos = json.find(':', pos);
if (pos == std::string::npos) return 0.0;
while (pos < json.size() && (json[pos] == ':' || json[pos] == ' ' || json[pos] == '\t' || json[pos] == '\n')) pos++;
return std::stod(json.substr(pos));
}
static int json_read_int(const std::string &json, const std::string &key) {
return static_cast<int>(json_read_double(json, key));
}
/* 从 JSON 中读取字符串值 */
static std::string json_read_string(const std::string &json, const std::string &key) {
auto pos = json.find("\"" + key + "\"");
if (pos == std::string::npos) return "";
pos = json.find(':', pos);
if (pos == std::string::npos) return "";
while (pos < json.size() && (json[pos] == ':' || json[pos] == ' ' || json[pos] == '\t' || json[pos] == '\n')) pos++;
if (pos >= json.size()) return "";
// 找到引号
if (json[pos] != '"') return "";
pos++;
std::string result;
while (pos < json.size() && json[pos] != '"') {
result += json[pos];
pos++;
}
return result;
}
/* 检查 JSON 中是否存在某个 key */
static bool json_has_key(const std::string &json, const std::string &key) {
return json.find("\"" + key + "\"") != std::string::npos;
}
/* 读取 JSON 数组 (如 "G": [0, 0, -9.8]) 到 double[3] */
static void json_read_double3(const std::string &json, const std::string &key, double out[3]) {
auto pos = json.find("\"" + key + "\"");
if (pos == std::string::npos) { out[0] = out[1] = out[2] = 0; return; }
pos = json.find('[', pos);
if (pos == std::string::npos) { out[0] = out[1] = out[2] = 0; return; }
pos++;
for (int i = 0; i < 3; i++) {
while (pos < json.size() && (json[pos] == ' ' || json[pos] == '\t' || json[pos] == '\n' || json[pos] == ',')) pos++;
char *end;
out[i] = std::strtod(json.c_str() + pos, &end);
pos = end - json.c_str();
}
}
/* 读取 JSON 数组到 double[6] */
static void json_read_double6(const std::string &json, const std::string &key, double out[6]) {
auto pos = json.find("\"" + key + "\"");
if (pos == std::string::npos) { for (int i=0;i<6;i++) out[i]=0; return; }
pos = json.find('[', pos);
if (pos == std::string::npos) { for (int i=0;i<6;i++) out[i]=0; return; }
pos++;
for (int i = 0; i < 6; i++) {
while (pos < json.size() && (json[pos]==' '||json[pos]=='\t'||json[pos]=='\n'||json[pos]==','||json[pos]==']')) pos++;
char *end;
out[i] = std::strtod(json.c_str() + pos, &end);
pos = end - json.c_str();
}
}
/* 解析 param.json */
static SimParams read_params(const std::string &path) {
std::string buf = read_file(path);
SimParams p;
p.box_a = json_read_double(buf, "box_a");
p.NT = json_read_int(buf, "NT");
p.DT = json_read_double(buf, "DT");
p.NSTEP = json_read_int(buf, "NSTEP");
p.warmup_steps = json_read_int(buf, "warmup_steps");
std::string m = json_read_string(buf, "method");
if (!m.empty()) p.method = m;
json_read_double3(buf, "G", p.G);
json_read_double3(buf, "B", p.B);
p.gravity_field = json_read_int(buf, "gravity_field");
p.gravity_interaction = json_read_int(buf, "gravity_interaction");
p.elastic_force = json_read_int(buf, "elastic_force");
p.damping_force = json_read_int(buf, "damping_force");
p.gravity_strength = json_read_double(buf, "gravity_strength");
p.driving_force = json_read_int(buf, "driving_force");
// save_trajectory 默认 1（全量），仅在 JSON 中存在该 key 时覆盖
if (json_has_key(buf, "save_trajectory"))
p.save_trajectory = json_read_int(buf, "save_trajectory");
json_read_double6(buf, "alpha", p.alpha);
p.ball_radius = json_read_double(buf, "ball_radius");
json_read_double3(buf, "ball_color", p.ball_color);
json_read_double3(buf, "box_color", p.box_color);
p.use_marker = json_read_int(buf, "use_marker");
p.camera_distance = json_read_double(buf, "camera_distance");
p.camera_elevation = json_read_double(buf, "camera_elevation");
p.camera_azimuth = json_read_double(buf, "camera_azimuth");
return p;
}
/* 读取 coord.txt */
static AtomData read_coord(const std::string &input_dir) {
std::string path = input_dir + "/coord.txt";
std::ifstream f(path);
if (!f) die("无法打开 " + path);
std::string header;
std::getline(f, header); // 跳过表头
AtomData a;
int id, fx, fy, fz;
double mass, rad, px, py, pz, vx, vy, vz;
std::string line;
while (std::getline(f, line)) {
if (line.empty() || line[0] == '#') continue;
int n_parsed = std::sscanf(line.c_str(), "%d %lf %lf %lf %lf %lf %lf %lf %lf %d %d %d",
&id, &mass, &rad, &px, &py, &pz, &vx, &vy, &vz, &fx, &fy, &fz);
if (n_parsed == 9) {
fx = fy = fz = 0;
} else if (n_parsed != 12) {
continue;
}
a.ids.push_back(id);
a.masses.push_back(mass);
a.radii.push_back(rad);
a.pos_0.push_back(px); a.pos_0.push_back(py); a.pos_0.push_back(pz);
a.vel_0.push_back(vx); a.vel_0.push_back(vy); a.vel_0.push_back(vz);
a.fixed.push_back(fx); a.fixed.push_back(fy); a.fixed.push_back(fz);
}
if (a.ids.empty()) die("coord.txt 中没有原子数据");
return a;
}
/* 读取 connection.txt 和 bond.txt */
static BondData read_bonds(const std::string &input_dir) {
BondData b;
std::string conn_path = input_dir + "/connection.txt";
std::ifstream f(conn_path);
if (!f) return b; // 无成键
std::string header;
std::getline(f, header); // 跳过表头
// 先读取 bond.txt 获得键参数映射
std::string bond_path = input_dir + "/bond.txt";
std::ifstream fb(bond_path);
int a1, a2;
std::string bond_name;
std::vector<std::tuple<int, int, std::string>> conn_lines;
while (f >> a1 >> a2 >> bond_name) {
conn_lines.emplace_back(a1 - 1, a2 - 1, bond_name);
}
for (auto &[i, j, name] : conn_lines) {
double k = 1.0, r0 = 2.0;
if (fb) {
fb.clear();
fb.seekg(0);
std::string bn, header;
double bk, br;
std::getline(fb, header); // 跳过表头行
while (fb >> bn >> bk >> br) {
if (bn == name) {
k = bk;
r0 = br;
break;
}
}
}
b.pairs.push_back(i);
b.pairs.push_back(j);
b.stiffness.push_back(k);
b.rest_lengths.push_back(r0);
}
return b;
}
/* 读取 driver.txt */
static DriverData read_driver(const std::string &input_dir, const AtomData &atoms) {
DriverData d;
std::string path = input_dir + "/driver.txt";
std::ifstream f(path);
if (!f) { std::cerr << "[C++-engine] 警告: 无法打开 " << path << std::endl; return d; }
std::string header;
std::getline(f, header); // skip header
int n;
double ax, ay, az, fx, fy, fz, px, py, pz;
std::string period_str;
while (f >> n >> ax >> ay >> az >> fx >> fy >> fz >> px >> py >> pz >> period_str) {
// Find atom index by id
int idx = -1;
for (size_t i = 0; i < atoms.ids.size(); i++) {
if (atoms.ids[i] == n) { idx = i; break; }
}
if (idx < 0) {
std::cerr << "[C++-engine] 警告: driver.txt 原子 " << n << " 不在 coord.txt 中" << std::endl;
continue;
}
d.atom_idx.push_back(idx);
d.amp_x.push_back(ax); d.amp_y.push_back(ay); d.amp_z.push_back(az);
d.freq_x.push_back(fx); d.freq_y.push_back(fy); d.freq_z.push_back(fz);
// Convert degrees to radians
const double DEG2RAD = M_PI / 180.0;
d.phi_x.push_back(px * DEG2RAD);
d.phi_y.push_back(py * DEG2RAD);
d.phi_z.push_back(pz * DEG2RAD);
if (period_str == "all") {
d.has_period.push_back(0);
d.period_cycles.push_back(-1.0);
} else {
d.has_period.push_back(1);
d.period_cycles.push_back(std::stod(period_str));
}
d.freeze_x.push_back(0.0);
d.freeze_y.push_back(0.0);
d.freeze_z.push_back(0.0);
d.n_drivers++;
}
if (d.n_drivers > 0)
std::cout << "[C++-engine] 已加载驱动力: " << d.n_drivers << " 条定义" << std::endl;
return d;
}
// ========================================================================
// 物理核心
// ========================================================================
/* 加速度计算（各力独立开关控制）——与 Python compute_acceleration 一致 */
static void compute_acceleration(
int n,
const double *x, const double *y, const double *z,
const double *vx, const double *vy, const double *vz,
const double *m, const double G[3], const double B[3],
const BondData &bonds,
int gravity_field, int gravity_interaction,
int elastic_force, int damping_force,
double gravity_strength,
double *ax, double *ay, double *az)
{
// 清零
std::fill(ax, ax + n, 0.0);
std::fill(ay, ay + n, 0.0);
std::fill(az, az + n, 0.0);
// 均匀重力场
if (gravity_field) {
for (int i = 0; i < n; i++) {
ax[i] += G[0];
ay[i] += G[1];
az[i] += G[2];
}
}
// 阻尼
if (damping_force) {
for (int i = 0; i < n; i++) {
ax[i] -= B[0] * vx[i] / m[i];
ay[i] -= B[1] * vy[i] / m[i];
az[i] -= B[2] * vz[i] / m[i];
}
}
// 弹簧力
if (elastic_force) {
int nb = static_cast<int>(bonds.stiffness.size());
for (int b = 0; b < nb; b++) {
int i = bonds.pairs[b * 2];
int j = bonds.pairs[b * 2 + 1];
double dx = x[j] - x[i];
double dy = y[j] - y[i];
double dz = z[j] - z[i];
double dist = std::sqrt(dx * dx + dy * dy + dz * dz);
if (dist < 1e-12) continue;
double stretch = dist - bonds.rest_lengths[b];
double fmag = bonds.stiffness[b] * stretch;
double ux = dx / dist, uy = dy / dist, uz = dz / dist;
double fx = fmag * ux, fy = fmag * uy, fz = fmag * uz;
ax[i] += fx / m[i]; ay[i] += fy / m[i]; az[i] += fz / m[i];
ax[j] -= fx / m[j]; ay[j] -= fy / m[j]; az[j] -= fz / m[j];
}
}
// 万有引力（所有原子对之间）
if (gravity_interaction) {
for (int i = 0; i < n; i++) {
for (int j = i + 1; j < n; j++) {
double dx = x[j] - x[i];
double dy = y[j] - y[i];
double dz = z[j] - z[i];
double r2 = dx * dx + dy * dy + dz * dz;
if (r2 <= 1e-12) continue;
double r = std::sqrt(r2);
double f_mag = gravity_strength * m[i] * m[j] / r2;
double fx_g = f_mag * dx / r;
double fy_g = f_mag * dy / r;
double fz_g = f_mag * dz / r;
ax[i] += fx_g / m[i]; ay[i] += fy_g / m[i]; az[i] += fz_g / m[i];
ax[j] -= fx_g / m[j]; ay[j] -= fy_g / m[j]; az[j] -= fz_g / m[j];
}
}
}
}
/* 边界条件：clamp 位置 + 速度反转 ——与 Python Limit_in_box 一致 */
static void limit_in_box(double &pos, double &vel, double lo, double hi) {
if (pos > hi) { pos = hi; vel = -vel; }
if (pos < lo) { pos = lo; vel = -vel; }
}
/* 周期边界回绕（与 Python wrap_position 一致）*/
static void wrap_position(double &pos, double lo, double hi) {
if (pos > hi) pos = lo;
if (pos < lo) pos = hi;
}
// ========================================================================
// 四种积分方法（只做位置/速度更新，不含边界条件）
// 与 Python: Explicit_Euler_Method / Implicit_Euler_Method /
// Midpoint_Method / Leapfrog_Method 保持一致
// ========================================================================
/* ── 显式欧拉法 ──────────── */
static void explicit_euler_step(
int n, double *x, double *y, double *z,
double *vx, double *vy, double *vz,
const double *m, const double G[3], const double B[3],
const BondData &bonds, const int *fixed, double dt,
int gravity_field, int gravity_interaction,
int elastic_force, int damping_force,
double gravity_strength)
{
std::vector<double> ax(n), ay(n), az(n);
compute_acceleration(n, x, y, z, vx, vy, vz, m, G, B, bonds,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength,
ax.data(), ay.data(), az.data());
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
x[i] += vx[i] * dt;
y[i] += vy[i] * dt;
z[i] += vz[i] * dt;
vx[i] += ax[i] * dt;
vy[i] += ay[i] * dt;
vz[i] += az[i] * dt;
}
}
/* ── 隐式欧拉法 ──────────── */
static void implicit_euler_step(
int n, double *x, double *y, double *z,
double *vx, double *vy, double *vz,
const double *m, const double G[3], const double B[3],
const BondData &bonds, const int *fixed, double dt,
int gravity_field, int gravity_interaction,
int elastic_force, int damping_force,
double gravity_strength)
{
std::vector<double> ax(n), ay(n), az(n);
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) {
ax[i] = ay[i] = az[i] = 0;
continue;
}
double gamma_x = B[0] / m[i];
double gamma_y = B[1] / m[i];
double gamma_z = B[2] / m[i];
// 隐式更新速度（重力 + 阻尼）
double vxn = (vx[i] + G[0] * dt) / (1.0 + gamma_x * dt);
double vyn = (vy[i] + G[1] * dt) / (1.0 + gamma_y * dt);
double vzn = (vz[i] + G[2] * dt) / (1.0 + gamma_z * dt);
// 用隐式速度 + 当前位置算加速度（包含各力开关）
// 注意：Python 中 compute_acceleration(x, y, z, vx_next, ...) 用新速度+旧位置
double tpx = x[i], tpy = y[i], tpz = z[i];
compute_acceleration(1, &tpx, &tpy, &tpz, &vxn, &vyn, &vzn,
&m[i], G, B, bonds,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength,
&ax[i], &ay[i], &az[i]);
vx[i] += ax[i] * dt;
vy[i] += ay[i] * dt;
vz[i] += az[i] * dt;
x[i] += vx[i] * dt;
y[i] += vy[i] * dt;
z[i] += vz[i] * dt;
}
}
/* ── 中点法 ──────────── */
static void midpoint_step(
int n, double *x, double *y, double *z,
double *vx, double *vy, double *vz,
const double *m, const double G[3], const double B[3],
const BondData &bonds, const int *fixed, double dt,
int gravity_field, int gravity_interaction,
int elastic_force, int damping_force,
double gravity_strength)
{
std::vector<double> ax(n), ay(n), az(n);
compute_acceleration(n, x, y, z, vx, vy, vz, m, G, B, bonds,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength,
ax.data(), ay.data(), az.data());
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
double x_mid = x[i] + 0.5 * vx[i] * dt;
double y_mid = y[i] + 0.5 * vy[i] * dt;
double z_mid = z[i] + 0.5 * vz[i] * dt;
double vx_mid = vx[i] + 0.5 * ax[i] * dt;
double vy_mid = vy[i] + 0.5 * ay[i] * dt;
double vz_mid = vz[i] + 0.5 * az[i] * dt;
x[i] += vx_mid * dt;
y[i] += vy_mid * dt;
z[i] += vz_mid * dt;
double ax_mid, ay_mid, az_mid;
compute_acceleration(1, &x_mid, &y_mid, &z_mid, &vx_mid, &vy_mid, &vz_mid,
&m[i], G, B, bonds,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength,
&ax_mid, &ay_mid, &az_mid);
vx[i] += ax_mid * dt;
vy[i] += ay_mid * dt;
vz[i] += az_mid * dt;
}
}
/* ── 蛙跳法（Velocity-Verlet）——与 Python Leapfrog_Method 一致 ── */
static void leapfrog_full_step(
int n, double *x, double *y, double *z,
double *vx, double *vy, double *vz,
const double *m, const double G[3], const double B[3],
const BondData &bonds, const int *fixed, double dt,
int gravity_field, int gravity_interaction,
int elastic_force, int damping_force,
double gravity_strength)
{
// 第一次加速度
std::vector<double> ax(n), ay(n), az(n);
compute_acceleration(n, x, y, z, vx, vy, vz, m, G, B, bonds,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength,
ax.data(), ay.data(), az.data());
// 半推速度：v_half = v + 0.5*a*dt (存入 vx, vy, vz)
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
vx[i] += ax[i] * dt * 0.5;
vy[i] += ay[i] * dt * 0.5;
vz[i] += az[i] * dt * 0.5;
}
// 全推位置（不含边界，边界在外层统一处理）
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
x[i] += vx[i] * dt; // vx 此时是 v_half
y[i] += vy[i] * dt;
z[i] += vz[i] * dt;
}
// 显式预测器：v_pred = v_half + 0.5*a_old*dt，用第一次加速度外推半步
// 包含所有力的贡献（标准 Velocity-Verlet 预测步）
std::vector<double> pred_vx(n), pred_vy(n), pred_vz(n);
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
pred_vx[i] = vx[i] + 0.5 * ax[i] * dt;
pred_vy[i] = vy[i] + 0.5 * ay[i] * dt;
pred_vz[i] = vz[i] + 0.5 * az[i] * dt;
}
// 用新位置 + 预测速度重算加速度
compute_acceleration(n, x, y, z, pred_vx.data(), pred_vy.data(), pred_vz.data(),
m, G, B, bonds,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength,
ax.data(), ay.data(), az.data());
// 速度后半步：v = v_half + 0.5*a_next*dt
// vx 仍为 v_half（未被覆盖），直接加上 0.5*a_next*dt
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
vx[i] += ax[i] * dt * 0.5;
vy[i] += ay[i] * dt * 0.5;
vz[i] += az[i] * dt * 0.5;
}
}
/* ── 分发器：调用对应积分方法 + 边界条件（与 Python apply_motion_update 一致）── */
static void apply_step(
const std::string &method,
int n, double *x, double *y, double *z,
double *vx, double *vy, double *vz,
const double *m, const double G[3], const double B[3],
const BondData &bonds, const int *fixed,
const double *pos_0,
double box_a, double dt,
int gravity_field, int gravity_interaction,
int elastic_force, int damping_force,
double gravity_strength)
{
// 积分
if (method == "explicit_euler") {
explicit_euler_step(n, x, y, z, vx, vy, vz, m, G, B, bonds, fixed, dt,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength);
} else if (method == "implicit_euler") {
implicit_euler_step(n, x, y, z, vx, vy, vz, m, G, B, bonds, fixed, dt,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength);
} else if (method == "midpoint") {
midpoint_step(n, x, y, z, vx, vy, vz, m, G, B, bonds, fixed, dt,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength);
} else if (method == "leapfrog") {
leapfrog_full_step(n, x, y, z, vx, vy, vz, m, G, B, bonds, fixed, dt,
gravity_field, gravity_interaction,
elastic_force, damping_force, gravity_strength);
} else {
die("未知算法: " + method);
}
// 边界条件（与 Python Limit_in_box 一致）
for (int i = 0; i < n; i++) {
if (fixed[i*3+0] && fixed[i*3+1] && fixed[i*3+2]) continue;
limit_in_box(x[i], vx[i], -box_a, box_a);
limit_in_box(y[i], vy[i], -box_a, box_a);
limit_in_box(z[i], vz[i], -box_a, box_a);
}
// 周期边界回绕（与 Python wrap_position 一致）
for (int i = 0; i < n; i++) {
wrap_position(x[i], -box_a, box_a);
wrap_position(y[i], -box_a, box_a);
wrap_position(z[i], -box_a, box_a);
}
// 逐自由度固定约束（与 Python apply_fixed_constraints 一致）
for (int i = 0; i < n; i++) {
if (fixed[i*3+0]) { x[i] = pos_0[i*3]; vx[i] = 0.0; }
if (fixed[i*3+1]) { y[i] = pos_0[i*3+1]; vy[i] = 0.0; }
if (fixed[i*3+2]) { z[i] = pos_0[i*3+2]; vz[i] = 0.0; }
}
}
// ========================================================================
// 驱动力应用
// ========================================================================
static void apply_driving_force(
int n, double *x, double *y, double *z,
double *vx, double *vy, double *vz,
double t, int step, double dt,
DriverData &drivers)
{
if (drivers.n_drivers == 0) return;
for (int d = 0; d < drivers.n_drivers; d++) {
int idx = drivers.atom_idx[d];
// Check period limits
if (drivers.has_period[d]) {
double max_freq = std::max({std::fabs(drivers.freq_x[d]),
std::fabs(drivers.freq_y[d]),
std::fabs(drivers.freq_z[d])});
int period_steps = 0;
if (max_freq > 1e-12) {
period_steps = static_cast<int>(drivers.period_cycles[d] / max_freq / dt);
}
if (step > period_steps) {
// Frozen: keep last position, zero velocity
x[idx] = drivers.freeze_x[d];
y[idx] = drivers.freeze_y[d];
z[idx] = drivers.freeze_z[d];
vx[idx] = vy[idx] = vz[idx] = 0.0;
continue;
}
}
const double TWO_PI = 2.0 * M_PI;
double px = drivers.amp_x[d] * std::cos(TWO_PI * drivers.freq_x[d] * t + drivers.phi_x[d]);
double py = drivers.amp_y[d] * std::cos(TWO_PI * drivers.freq_y[d] * t + drivers.phi_y[d]);
double pz = drivers.amp_z[d] * std::cos(TWO_PI * drivers.freq_z[d] * t + drivers.phi_z[d]);
double vpx = -drivers.amp_x[d] * TWO_PI * drivers.freq_x[d] * std::sin(TWO_PI * drivers.freq_x[d] * t + drivers.phi_x[d]);
double vpy = -drivers.amp_y[d] * TWO_PI * drivers.freq_y[d] * std::sin(TWO_PI * drivers.freq_y[d] * t + drivers.phi_y[d]);
double vpz = -drivers.amp_z[d] * TWO_PI * drivers.freq_z[d] * std::sin(TWO_PI * drivers.freq_z[d] * t + drivers.phi_z[d]);
x[idx] = px; y[idx] = py; z[idx] = pz;
vx[idx] = vpx; vy[idx] = vpy; vz[idx] = vpz;
// Record freeze position at the last driving step
if (drivers.has_period[d]) {
double max_freq = std::max({std::fabs(drivers.freq_x[d]),
std::fabs(drivers.freq_y[d]),
std::fabs(drivers.freq_z[d])});
int period_steps = 0;
if (max_freq > 1e-12) {
period_steps = static_cast<int>(drivers.period_cycles[d] / max_freq / dt);
}
if (step == period_steps) {
drivers.freeze_x[d] = px;
drivers.freeze_y[d] = py;
drivers.freeze_z[d] = pz;
}
}
}
}
// ========================================================================
// display.txt 输出（save_trajectory=0 时使用）
// ========================================================================
static void write_display_txt(
const std::string &path,
const std::vector<double> &x, const std::vector<double> &y,
const std::vector<double> &z, const std::vector<double> &vx,
const std::vector<double> &vy, const std::vector<double> &vz,
int n_steps, int n_atoms,
const SimParams &params, const AtomData &atoms)
{
std::ofstream f(path);
if (!f) die("无法写入 " + path);
std::cout << "[Cpp-engine] 正在写入显示数据…" << std::endl;
double T_total = params.NT * params.DT;
f << "number of frames: " << n_steps << "\n";
f << "number of particles: " << n_atoms << "\n";
f << "DT: " << params.DT << "\n";
f << "NSTEP: " << params.NSTEP << "\n";
f << "method: " << params.method << "\n";
f << "warmup_steps: " << params.warmup_steps << "\n";
f << "dynamic_steps: " << (params.NT - params.warmup_steps) << "\n";
f << "T_total: " << T_total << "\n";
f << "box_a: " << params.box_a << "\n";
f << "driving_force: " << params.driving_force << "\n";
f << "alpha: " << params.alpha[0] << "," << params.alpha[1] << "," << params.alpha[2] << ","
<< params.alpha[3] << "," << params.alpha[4] << "," << params.alpha[5] << "\n";
f << "ball_radius: " << params.ball_radius << "\n";
f << "ball_color_r: " << params.ball_color[0] << "\n";
f << "ball_color_g: " << params.ball_color[1] << "\n";
f << "ball_color_b: " << params.ball_color[2] << "\n";
f << "box_color_r: " << params.box_color[0] << "\n";
f << "box_color_g: " << params.box_color[1] << "\n";
f << "box_color_b: " << params.box_color[2] << "\n";
f << "use_marker: " << params.use_marker << "\n";
f << "camera_distance: " << params.camera_distance << "\n";
f << "camera_elevation: " << params.camera_elevation << "\n";
f << "camera_azimuth: " << params.camera_azimuth << "\n\n";
f << std::fixed << std::setprecision(6);
for (int t = 0; t < n_steps; t++) {
f << "frame: " << (t + 1) << "\n";
f << "n x y z vx vy vz\n";
for (int i = 0; i < n_atoms; i++) {
int base = t * n_atoms + i;
f << std::setw(3) << atoms.ids[i]
<< std::setw(12) << x[base]
<< std::setw(12) << y[base]
<< std::setw(12) << z[base]
<< std::setw(12) << vx[base]
<< std::setw(12) << vy[base]
<< std::setw(12) << vz[base] << "\n";
}
}
}
// ========================================================================
// JSON 输出
// ========================================================================
static void write_trajectory_json(
const std::string &path,
const std::vector<double> &x, const std::vector<double> &y,
const std::vector<double> &z, const std::vector<double> &vx,
const std::vector<double> &vy, const std::vector<double> &vz,
int n_steps, int n_atoms,
const SimParams &params, const AtomData &atoms, const BondData &bonds)
{
std::ofstream f(path);
if (!f) die("无法写入 " + path);
std::cout << "[Cpp-engine] 正在写入轨迹数据…" << std::endl;
f << std::setprecision(8);
f << "{\n";
// 轨迹数组
const std::string names[] = {"traj_x","traj_y","traj_z","traj_vx","traj_vy","traj_vz"};
const std::vector<double> *arrs[] = {&x, &y, &z, &vx, &vy, &vz};
for (int a = 0; a < 6; a++) {
f << " \"" << names[a] << "\": [\n";
const auto &data = *arrs[a];
for (int t = 0; t < n_steps; t++) {
f << " [";
for (int i = 0; i < n_atoms; i++) {
f << data[t * n_atoms + i];
if (i < n_atoms - 1) f << ',';
}
f << ']';
if (t < n_steps - 1) f << ',';
f << '\n';
}
f << " ],\n";
}
// 标量参数
f << " \"NT\": " << params.NT << ",\n";
f << " \"DT\": " << params.DT << ",\n";
f << " \"NSTEP\": " << params.NSTEP << ",\n";
f << " \"method\": \"" << params.method << "\",\n";
f << " \"warmup_steps\": " << params.warmup_steps << ",\n";
f << " \"G\": [" << params.G[0] << ", " << params.G[1] << ", " << params.G[2] << "],\n";
f << " \"B\": [" << params.B[0] << ", " << params.B[1] << ", " << params.B[2] << "],\n";
// 原子信息
f << " \"atom_ids\": [";
for (size_t i = 0; i < atoms.ids.size(); i++) {
if (i > 0) f << ',';
f << atoms.ids[i];
}
f << "],\n";
f << " \"atom_masses\": [";
for (size_t i = 0; i < atoms.masses.size(); i++) {
if (i > 0) f << ',';
f << atoms.masses[i];
}
f << "],\n";
// 成键
f << " \"bond_pairs\": [";
for (size_t b = 0; b < bonds.stiffness.size(); b++) {
if (b > 0) f << ',';
f << "[" << bonds.pairs[b * 2] << ", " << bonds.pairs[b * 2 + 1] << "]";
}
f << "],\n";
f << " \"bond_stiffness\": [";
for (size_t b = 0; b < bonds.stiffness.size(); b++) {
if (b > 0) f << ',';
f << bonds.stiffness[b];
}
f << "],\n";
f << " \"bond_rest_lengths\": [";
for (size_t b = 0; b < bonds.rest_lengths.size(); b++) {
if (b > 0) f << ',';
f << bonds.rest_lengths[b];
}
f << "],\n";
f << " \"driving_force\": " << params.driving_force << "\n";
f << "}\n";
}
// ========================================================================
// 主函数
// ========================================================================
int main(int argc, char **argv) {
if (argc < 4) {
std::cerr << "用法: " << argv[0] << " <input_dir> <output_dir> <param_json>" << std::endl;
return 1;
}
std::string input_dir = argv[1];
std::string output_dir = argv[2];
std::string param_path = argv[3];
auto t0 = std::chrono::high_resolution_clock::now();
// 读取参数和输入
SimParams params = read_params(param_path);
AtomData atoms = read_coord(input_dir);
BondData bonds = read_bonds(input_dir);
DriverData drivers;
if (params.driving_force) {
drivers = read_driver(input_dir, atoms);
}
std::cout << "[C++-engine] 原子数=" << atoms.ids.size()
<< ", 键数=" << bonds.stiffness.size()
<< ", NT=" << params.NT << ", DT=" << params.DT
<< ", method=" << params.method << std::endl;
int n = static_cast<int>(atoms.ids.size());
// 初始化位置/速度
std::vector<double> x(n), y(n), z(n), vx(n), vy(n), vz(n);
for (int i = 0; i < n; i++) {
x[i] = atoms.pos_0[i * 3];
y[i] = atoms.pos_0[i * 3 + 1];
z[i] = atoms.pos_0[i * 3 + 2];
vx[i] = atoms.vel_0[i * 3];
vy[i] = atoms.vel_0[i * 3 + 1];
vz[i] = atoms.vel_0[i * 3 + 2];
}
// 分配轨迹缓冲区
int record_steps = params.NT - params.warmup_steps;
int nstep_sampling = (params.save_trajectory == 0) ? params.NSTEP : 1;
int buf_steps = (params.save_trajectory == 0) ? (record_steps / nstep_sampling) : record_steps;
std::vector<double> traj_x(buf_steps * n);
std::vector<double> traj_y(buf_steps * n);
std::vector<double> traj_z(buf_steps * n);
std::vector<double> traj_vx(buf_steps * n);
std::vector<double> traj_vy(buf_steps * n);
std::vector<double> traj_vz(buf_steps * n);
// 预热
// 初始时刻 t=0 驱动力（与 Python run_simulation 一致）
if (params.driving_force)
apply_driving_force(n, x.data(), y.data(), z.data(), vx.data(), vy.data(), vz.data(), 0.0, 0, params.DT, drivers);
for (int s = 0; s < params.warmup_steps; s++) {
double tw = (s + 1) * params.DT;
if (params.driving_force)
apply_driving_force(n, x.data(), y.data(), z.data(), vx.data(), vy.data(), vz.data(), tw, s, params.DT, drivers);
apply_step(params.method, n, x.data(), y.data(), z.data(),
vx.data(), vy.data(), vz.data(),
atoms.masses.data(), params.G, params.B,
bonds, atoms.fixed.data(),
atoms.pos_0.data(),
params.box_a, params.DT,
params.gravity_field, params.gravity_interaction,
params.elastic_force, params.damping_force, params.gravity_strength);
}
// 记录
int _prog_int = record_steps / 100;
if (_prog_int < 1) _prog_int = 1;
int si = 0; // 采样帧索引
for (int s = 0; s < record_steps; s++) {
if (s % _prog_int == 0 && s > 0) {
std::cout << "[Cpp-engine] progress: " << s << "/" << record_steps << std::endl;
}
double t = (s + params.warmup_steps) * params.DT;
if (params.driving_force)
apply_driving_force(n, x.data(), y.data(), z.data(), vx.data(), vy.data(), vz.data(), t, s, params.DT, drivers);
// 保存当前帧（采样模式仅每 NSTEP 步保存一次）
if (s % nstep_sampling == 0) {
for (int i = 0; i < n; i++) {
traj_x[si * n + i] = x[i];
traj_y[si * n + i] = y[i];
traj_z[si * n + i] = z[i];
traj_vx[si * n + i] = vx[i];
traj_vy[si * n + i] = vy[i];
traj_vz[si * n + i] = vz[i];
}
si++;
}
apply_step(params.method, n, x.data(), y.data(), z.data(),
vx.data(), vy.data(), vz.data(),
atoms.masses.data(), params.G, params.B,
bonds, atoms.fixed.data(),
atoms.pos_0.data(),
params.box_a, params.DT,
params.gravity_field, params.gravity_interaction,
params.elastic_force, params.damping_force, params.gravity_strength);
}
// 输出轨迹
if (params.save_trajectory == 0) {
std::string out_path = output_dir + "/display.txt";
write_display_txt(out_path, traj_x, traj_y, traj_z, traj_vx, traj_vy, traj_vz,
si, n, params, atoms);
} else {
std::string out_path = output_dir + "/trajectory.txt";
write_trajectory_json(out_path, traj_x, traj_y, traj_z, traj_vx, traj_vy, traj_vz,
record_steps, n, params, atoms, bonds);
}
auto t1 = std::chrono::high_resolution_clock::now();
double elapsed = std::chrono::duration<double>(t1 - t0).count();
std::cout << "[C++-engine] 计算完成: " << record_steps << " 步, " << elapsed << " s" << std::endl;
return 0;
}
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