runner_pt.cpp 23.4 KB
Newer Older
1
#include "runner_pt.h"
2
#include <fstream>
3
#include "util.h"
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

namespace loadl {

enum {
	S_IDLE,
	S_BUSY,
	S_READY_FOR_GLOBAL,
	S_TIMEUP,

	A_CONTINUE,
	A_EXIT,
	A_NEW_JOB,
	A_PROCESS_DATA_NEW_JOB,

	// global update status response
	GA_DONE,
	GA_SKIP,
	GA_CALC_WEIGHT,

23
	MASTER = 0
24 25
};

26 27 28 29 30 31
enum {
	TR_CONTINUE,
	TR_CHECKPOINT,
	TR_TIMEUP,
};

Lukas Weber's avatar
Lukas Weber committed
32
pt_chain_run::pt_chain_run(const pt_chain &chain, int run_id) : id{chain.id}, run_id{run_id} {
33 34
	rank_to_pos.resize(chain.params.size());
	weight_ratios.resize(chain.params.size(), -1);
35
	switch_partners.resize(chain.params.size());
Lukas Weber's avatar
Lukas Weber committed
36

37 38 39 40
	last_visited.resize(chain.params.size());

	for(size_t i = 0; i < rank_to_pos.size(); i++) {
		rank_to_pos[i] = i;
41 42 43
	}
}

44 45 46 47
void pt_chain_run::clear_histograms() {
	std::fill(last_visited.begin(), last_visited.end(), 0);
}

48
pt_chain_run pt_chain_run::checkpoint_read(const iodump::group &g) {
49 50 51
	pt_chain_run run;
	g.read("id", run.id);
	g.read("run_id", run.run_id);
52
	g.read("rank_to_pos", run.rank_to_pos);
53 54 55 56
	g.read("last_visited", run.last_visited);
	uint8_t swap_odd;
	g.read("swap_odd", swap_odd);
	run.swap_odd = swap_odd;
57

58
	run.weight_ratios.resize(run.rank_to_pos.size(), -1);
59
	run.switch_partners.resize(run.rank_to_pos.size());
60 61 62 63

	return run;
}

64
void pt_chain_run::checkpoint_write(const iodump::group &g) {
65 66
	g.write("id", id);
	g.write("run_id", run_id);
67
	g.write("rank_to_pos", rank_to_pos);
68 69
	g.write("last_visited", last_visited);
	g.write("swap_odd", static_cast<uint8_t>(swap_odd));
70 71 72 73
}

void pt_chain::checkpoint_read(const iodump::group &g) {
	g.read("params", params);
74 75 76
	g.read("rejection_rates", rejection_rates);
	g.read("rejection_rate_entries", rejection_rate_entries);

77 78 79 80 81 82
	g.read("nup_histogram", nup_histogram);
	g.read("ndown_histogram", ndown_histogram);
	g.read("entries_before_optimization", entries_before_optimization);
}

void pt_chain::checkpoint_write(const iodump::group &g) {
83
	g.write("params", params);
84 85
	g.write("rejection_rates", rejection_rates);
	g.write("rejection_rate_entries", rejection_rate_entries);
86 87 88
	g.write("nup_histogram", nup_histogram);
	g.write("ndown_histogram", ndown_histogram);
	g.write("entries_before_optimization", entries_before_optimization);
89 90
}

91
void pt_chain::clear_histograms() {
Lukas Weber's avatar
Lukas Weber committed
92 93
	rejection_rate_entries[0] = 0;
	rejection_rate_entries[1] = 0;
94
	std::fill(rejection_rates.begin(), rejection_rates.end(), 0);
95 96 97 98
	std::fill(nup_histogram.begin(), nup_histogram.end(), 0);
	std::fill(ndown_histogram.begin(), ndown_histogram.end(), 0);
}

99

100 101 102
// https://arxiv.org/pdf/1905.02939.pdf
std::tuple<double, double> pt_chain::optimize_params() {
	std::vector<double> rejection_est(rejection_rates);
Lukas Weber's avatar
Lukas Weber committed
103
	bool odd = false;
104
	for(auto& r : rejection_est) {
Lukas Weber's avatar
Lukas Weber committed
105 106
		r /= rejection_rate_entries[odd];
		odd = !odd;
107
	}
108

109
	std::vector<double> comm_barrier(params.size());
Lukas Weber's avatar
Lukas Weber committed
110

111

112
	double sum{};
113
	double efficiency{};
114 115 116
	for(size_t i = 0; i < comm_barrier.size()-1; i++) {
		comm_barrier[i] = sum;
		sum += rejection_est[i]; 
117
		efficiency += rejection_est[i]/(1-rejection_est[i]);
118
	}
119 120 121 122 123 124 125 126 127 128 129
	comm_barrier[comm_barrier.size()-1] = sum;

	monotonic_interpolator lambda{comm_barrier, params};
	double convergence{};

	for(size_t i = 1; i < params.size()-1; i++) {
		double new_param = lambda(sum*i/(params.size()-1));
		double d = (new_param - params[i]);
		
		convergence += d*d;
		params[i] = new_param;
130
	}
Lukas Weber's avatar
Lukas Weber committed
131

132
	convergence = sqrt(convergence)/params.size();
Lukas Weber's avatar
Lukas Weber committed
133

134 135 136
	double round_trip_rate = (1+sum)/(1+efficiency);

	return std::tie(round_trip_rate, convergence);
137 138 139
}

bool pt_chain::is_done() {
140
	return sweeps >= target_sweeps + target_thermalization;
141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166
}

int runner_pt_start(jobinfo job, const mc_factory &mccreator, int argc, char **argv) {
	MPI_Init(&argc, &argv);

	int rank;
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);

	if(rank == 0) {
		runner_pt_master r{std::move(job)};
		r.start();
	} else {
		runner_pt_slave r{std::move(job), mccreator};
		r.start();
	}

	MPI_Finalize();

	return 0;
}

runner_pt_master::runner_pt_master(jobinfo job) : job_{std::move(job)} {
	rng_ = std::make_unique<random_number_generator>();
}

void runner_pt_master::construct_pt_chains() {
167 168 169
	std::string pt_param =
	    job_.jobfile["jobconfig"].get<std::string>("parallel_tempering_parameter");

170 171 172
	for(size_t i = 0; i < job_.task_names.size(); i++) {
		auto task = job_.jobfile["tasks"][job_.task_names[i]];

Lukas Weber's avatar
Lukas Weber committed
173
		auto [chain_id, chain_pos] = task.get<std::pair<int, int>>("pt_chain");
174 175 176 177 178
		if(chain_id < 0 || chain_pos < 0) {
			throw std::runtime_error{"parallel tempering pt_chain indices must be nonnegative"};
		}

		if(chain_id >= static_cast<int>(pt_chains_.size())) {
179
			pt_chains_.resize(chain_id + 1);
180 181 182 183 184 185
		}

		auto &chain = pt_chains_.at(chain_id);
		chain.id = chain_id;

		if(chain_pos >= static_cast<int>(chain.task_ids.size())) {
186
			chain.task_ids.resize(chain_pos + 1, -1);
187
			chain.params.resize(chain_pos + 1);
188
		}
189

190 191 192 193
		if(chain.task_ids.at(chain_pos) != -1) {
			throw std::runtime_error{"parallel tempering pt_chain map not unique"};
		}

194
		chain.params.at(chain_pos) = task.get<double>(pt_param);
195 196
		chain.task_ids.at(chain_pos) = i;

Lukas Weber's avatar
Lukas Weber committed
197 198
		const char *pt_sweep_error =
		    "in parallel tempering mode, sweeps are measured in global updates and need to be the "
199
		    "same within each chain: {} = {} != {}";
200

201
		int target_sweeps = task.get<int>("sweeps");
202
		if(chain.target_sweeps >= 0 && target_sweeps != chain.target_sweeps) {
Lukas Weber's avatar
Lukas Weber committed
203 204
			throw std::runtime_error{
			    fmt::format(pt_sweep_error, "target_sweeps", chain.target_sweeps, target_sweeps)};
205
		}
206
		chain.target_sweeps = target_sweeps;
Lukas Weber's avatar
Lukas Weber committed
207

208
		int target_thermalization = task.get<int>("thermalization");
Lukas Weber's avatar
Lukas Weber committed
209 210 211 212 213
		if(chain.target_thermalization >= 0 &&
		   target_thermalization != chain.target_thermalization) {
			throw std::runtime_error{fmt::format(pt_sweep_error, "thermalization",
			                                     chain.target_thermalization,
			                                     target_thermalization)};
214
		}
215
		chain.target_thermalization = target_thermalization;
Lukas Weber's avatar
Lukas Weber committed
216

217
		int sweeps_per_global_update = task.get<int>("pt_sweeps_per_global_update");
Lukas Weber's avatar
Lukas Weber committed
218
		int sweeps = job_.read_dump_progress(i) / sweeps_per_global_update;
219 220
		if(chain.sweeps >= 0 && sweeps != chain.sweeps) {
			throw std::runtime_error{fmt::format(pt_sweep_error, "sweeps", chain.sweeps != sweeps)};
221
		}
222
		chain.sweeps = sweeps;
223
	}
Lukas Weber's avatar
Lukas Weber committed
224

225 226 227 228 229
	chain_len_ = -1;
	for(auto &c : pt_chains_) {
		if(c.id == -1) {
			throw std::runtime_error{"parallel tempering pt_chain map contains gaps"};
		}
230

231 232 233
		if(chain_len_ != -1 && chain_len_ != static_cast<int>(c.task_ids.size())) {
			throw std::runtime_error{"parallel tempering pt_chains do not have the same length"};
		}
234

235
		chain_len_ = c.task_ids.size();
236 237 238

		c.nup_histogram.resize(chain_len_);
		c.ndown_histogram.resize(chain_len_);
239

240 241
		c.rejection_rates.resize(chain_len_-1);

242 243 244
		if(po_config_.enabled) {
			c.entries_before_optimization = po_config_.nsamples_initial;
		}
245 246
	}
	if(chain_len_ == -1) {
247 248 249
		throw std::runtime_error{
		    "parallel tempering pt_chain mapping missing. You need to specify 'pt_chain: "
		    "[chain_id, chain_position]' for every task in the job."};
250 251
	}

252 253 254 255
	if((num_active_ranks_ - 1) % chain_len_ != 0) {
		throw std::runtime_error{
		    "parallel tempering: number of ranks should be of the form chain_length*n+1 for best "
		    "efficiency"};
256 257 258 259 260 261 262
	}
}

void runner_pt_master::checkpoint_read() {
	construct_pt_chains();

	std::string master_dump_name = job_.jobdir() + "/pt_master.dump.h5";
263
	if(file_exists(master_dump_name)) {
264
		job_.log(fmt::format("master reading dump from '{}'", master_dump_name));
265 266 267 268 269 270
		iodump dump = iodump::open_readonly(master_dump_name);
		auto g = dump.get_root();

		rng_->checkpoint_read(g.open_group("random_number_generator"));
		auto pt_chain_runs = g.open_group("pt_chain_runs");
		for(std::string name : pt_chain_runs) {
271 272
			pt_chain_runs_.emplace_back(
			    pt_chain_run::checkpoint_read(pt_chain_runs.open_group(name)));
273 274
		}

275 276 277 278 279
		auto pt_chains = g.open_group("pt_chains");
		for(std::string name : pt_chains) {
			int id = std::stoi(name);
			pt_chains_.at(id).checkpoint_read(pt_chains.open_group(name));
		}
280 281 282
	}
}

283 284 285 286 287 288 289 290 291 292 293 294 295 296
void runner_pt_master::write_params_yaml() {
	using namespace YAML;
	Emitter params;
	params << BeginMap;
	for(auto c : pt_chains_) {
		params << Key << fmt::format("chain{:04d}", c.id);
		params << Value << Flow << c.params;
	}
	params << EndMap;

	std::ofstream file{job_.jobdir() + "/pt_optimized_params.yml"};
	file << params.c_str() << "\n";
}

297 298 299 300 301 302 303 304 305 306 307 308 309 310 311
void runner_pt_master::write_param_optimization_stats() {
	std::string stat_name = job_.jobdir() + "/pt_param_stats.h5";
	iodump stat = iodump::open_readwrite(stat_name);
	auto g = stat.get_root();

	g.write("chain_length", chain_len_);
	
	for(auto &chain : pt_chains_) {
		auto cg = g.open_group(fmt::format("chain{:04d}", chain.id));
		std::vector<double> f(chain_len_);
		for(size_t i = 0; i < f.size(); i++) {
			f[i] = chain.nup_histogram[i]*1./(chain.ndown_histogram[i] + chain.nup_histogram[i]);
		}
		cg.insert_back("f", f);
		cg.insert_back("params", chain.params);
312 313

		std::vector<double> rejection_est(chain.rejection_rates);
Lukas Weber's avatar
Lukas Weber committed
314
		bool odd = false;
315
		for(auto &r : rejection_est) {
Lukas Weber's avatar
Lukas Weber committed
316 317
			r /= chain.rejection_rate_entries[odd];
			odd = !odd;
318 319 320
		}

		cg.insert_back("rejection_rates", rejection_est);
321 322 323
	}
}

324 325 326 327
void runner_pt_master::checkpoint_write() {
	std::string master_dump_name = job_.jobdir() + "/pt_master.dump.h5";

	job_.log(fmt::format("master: checkpoint {}", master_dump_name));
328

329 330 331 332 333 334
	iodump dump = iodump::create(master_dump_name);
	auto g = dump.get_root();

	rng_->checkpoint_write(g.open_group("random_number_generator"));
	auto pt_chain_runs = g.open_group("pt_chain_runs");
	for(auto &c : pt_chain_runs_) {
335 336
		c.checkpoint_write(
		    pt_chain_runs.open_group(fmt::format("chain{:04d}_run{:04d}", c.id, c.run_id)));
337 338
	}

339 340 341 342 343
	auto pt_chains = g.open_group("pt_chains");
	for(auto &c : pt_chains_) {
		c.checkpoint_write(pt_chains.open_group(fmt::format("{:04d}", c.id)));
	}

344
	if(po_config_.enabled) {
345 346
		write_params_yaml();
	}
347 348 349 350 351 352
}

void runner_pt_master::start() {
	MPI_Comm_size(MPI_COMM_WORLD, &num_active_ranks_);


353 354 355
	po_config_.enabled =
	    job_.jobfile["jobconfig"].defined("pt_parameter_optimization");
	if(po_config_.enabled) {
356
		job_.log("using feedback parameter optimization");
357 358 359
		const auto &po = job_.jobfile["jobconfig"]["pt_parameter_optimization"];
		po_config_.nsamples_initial = po.get<int>("nsamples_initial");
		po_config_.nsamples_growth = po.get<double>("nsamples_growth");
360 361
	}

362 363 364
	job_.log(fmt::format("starting job '{}' in parallel tempering mode", job_.jobname));
	checkpoint_read();

365 366
	std::vector<int> group_idx(num_active_ranks_);
	for(int i = 1; i < num_active_ranks_; i++) {
Lukas Weber's avatar
Lukas Weber committed
367
		group_idx[i] = (i - 1) / chain_len_;
368
	}
Lukas Weber's avatar
Lukas Weber committed
369
	MPI_Scatter(group_idx.data(), 1, MPI_INT, MPI_IN_PLACE, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
Lukas Weber's avatar
Lukas Weber committed
370

371 372
	MPI_Comm tmp;
	MPI_Comm_split(MPI_COMM_WORLD, MPI_UNDEFINED, 0, &tmp);
Lukas Weber's avatar
Lukas Weber committed
373

374 375
	for(int rank_section = 0; rank_section < (num_active_ranks_ - 1) / chain_len_; rank_section++) {
		assign_new_chain(rank_section);
376 377 378
	}

	time_last_checkpoint_ = MPI_Wtime();
379

380 381 382 383 384 385 386
	while(num_active_ranks_ > 1) {
		react();
		if(MPI_Wtime() - time_last_checkpoint_ > job_.checkpoint_time) {
			time_last_checkpoint_ = MPI_Wtime();
			checkpoint_write();
		}
	}
387
	checkpoint_write();
388 389 390 391 392 393 394
}

int runner_pt_master::schedule_chain_run() {
	int old_id = current_chain_id_;
	int nchains = pt_chains_.size();
	for(int i = 1; i <= nchains; i++) {
		if(!pt_chains_[(old_id + i) % nchains].is_done()) {
395 396
			current_chain_id_ = (old_id + i) % nchains;
			auto &chain = pt_chains_[current_chain_id_];
397
			chain.scheduled_runs++;
398

399 400 401 402 403 404 405 406 407
			int idx = 0;
			for(auto &run : pt_chain_runs_) {
				if(run.id == chain.id && run.run_id == chain.scheduled_runs) {
					return idx;
				}
				idx++;
			}

			pt_chain_runs_.emplace_back(chain, chain.scheduled_runs);
408
			return pt_chain_runs_.size() - 1;
409 410 411 412 413 414 415
		}
	}

	// everything done!
	return -1;
}

416
int runner_pt_master::assign_new_chain(int rank_section) {
417 418 419
	int chain_run_id = schedule_chain_run();

	for(int target = 0; target < chain_len_; target++) {
420
		int msg[3] = {-1, 0, 0};
Lukas Weber's avatar
ehhhh  
Lukas Weber committed
421
		if(chain_run_id >= 0) {
422 423 424 425
			auto &chain_run = pt_chain_runs_[chain_run_id];
			auto &chain = pt_chains_[chain_run.id];
			msg[0] = chain.task_ids[target];
			msg[1] = chain_run.run_id;
426
			msg[2] = chain.target_sweeps + chain.target_thermalization - chain.sweeps;
427 428 429 430
		} else {
			// this will prompt the slave to quit
			num_active_ranks_--;
		}
431
		MPI_Send(&msg, sizeof(msg) / sizeof(msg[0]), MPI_INT,
432
		         rank_section * chain_len_ + target + 1, 0, MPI_COMM_WORLD);
433
	}
434
	rank_to_chain_run_[rank_section] = chain_run_id;
435 436 437
	return chain_run_id;
}

Lukas Weber's avatar
Lukas Weber committed
438 439 440 441 442
void runner_pt_master::pt_param_optimization(pt_chain &chain, pt_chain_run &chain_run) {
	for(size_t rank = 0; rank < chain_run.rank_to_pos.size(); rank++) {
		if(chain_run.rank_to_pos[rank] == 0) {
			chain_run.last_visited[rank] = 1;
		}
Lukas Weber's avatar
Lukas Weber committed
443
		if(chain_run.rank_to_pos[rank] == static_cast<int>(chain_run.rank_to_pos.size()) - 1) {
Lukas Weber's avatar
Lukas Weber committed
444 445 446
			chain_run.last_visited[rank] = -1;
		}

Lukas Weber's avatar
Lukas Weber committed
447 448
		chain.ndown_histogram[chain_run.rank_to_pos[rank]] += chain_run.last_visited[rank] == -1;
		chain.nup_histogram[chain_run.rank_to_pos[rank]] += chain_run.last_visited[rank] == 1;
Lukas Weber's avatar
Lukas Weber committed
449
	}
Lukas Weber's avatar
Lukas Weber committed
450
	if(std::min(chain.rejection_rate_entries[0], chain.rejection_rate_entries[1]) >= chain.entries_before_optimization) {
451 452
		chain.entries_before_optimization *= po_config_.nsamples_growth;

453
		auto [fnonlinearity, convergence] = chain.optimize_params();
454 455 456
		job_.log(
		    fmt::format("chain {}: pt param optimization: entries={}, f nonlinearity={:.2g}, "
		                "convergence={:.2g}",
Lukas Weber's avatar
Lukas Weber committed
457
		                chain.id, chain.rejection_rate_entries[0], fnonlinearity, convergence));
458 459 460 461 462 463 464 465
		checkpoint_write();
		write_param_optimization_stats();
		chain.clear_histograms();

		for(auto &cr : pt_chain_runs_) {
			if(cr.id == chain.id) {
				cr.clear_histograms();
			}
466
		}
Lukas Weber's avatar
Lukas Weber committed
467 468 469
	}
}

470
void runner_pt_master::react() {
471
	int rank_status;
472
	MPI_Status stat;
473 474 475
	MPI_Recv(&rank_status, 1, MPI_INT, MPI_ANY_SOURCE, 0, MPI_COMM_WORLD, &stat);
	int rank = stat.MPI_SOURCE - 1;
	if(rank_status == S_BUSY) {
476
		int msg[1];
Lukas Weber's avatar
Lukas Weber committed
477
		MPI_Recv(msg, sizeof(msg) / sizeof(msg[0]), MPI_INT, rank + 1, 0, MPI_COMM_WORLD, &stat);
478 479
		int completed_sweeps = msg[0];

480
		int chain_run_id = rank_to_chain_run_[rank / chain_len_];
481 482 483
		auto &chain_run = pt_chain_runs_[chain_run_id];
		auto &chain = pt_chains_[chain_run.id];

484
		chain.sweeps += completed_sweeps;
485
		if(chain.is_done()) {
486 487 488 489
			chain.scheduled_runs--;
			int action = A_NEW_JOB;

			if(chain.scheduled_runs > 0) {
Lukas Weber's avatar
Lukas Weber committed
490 491
				job_.log(fmt::format("chain {} has enough sweeps. Waiting for {} busy rank sets.",
				                     chain.id, chain.scheduled_runs));
492 493 494 495
			} else {
				job_.log(fmt::format("chain {} rank {} is done. Merging.", chain.id, rank + 1));
				action = A_PROCESS_DATA_NEW_JOB;
				checkpoint_write();
496
			}
497 498 499 500
			for(int target = 0; target < chain_len_; target++) {
				send_action(action, rank / chain_len_ * chain_len_ + target + 1);
			}
			assign_new_chain(rank / chain_len_);
501
		} else {
502 503 504
			for(int target = 0; target < chain_len_; target++) {
				send_action(A_CONTINUE, rank / chain_len_ * chain_len_ + target + 1);
			}
505
		}
506 507
	} else if(rank_status == S_READY_FOR_GLOBAL) {
		int chain_run_id = rank_to_chain_run_[rank / chain_len_];
508 509
		auto &chain_run = pt_chain_runs_[chain_run_id];
		auto &chain = pt_chains_[chain_run.id];
510
		int rank_section = rank / chain_len_;
Lukas Weber's avatar
Lukas Weber committed
511

512
		if(po_config_.enabled) {
Lukas Weber's avatar
Lukas Weber committed
513
			pt_param_optimization(chain, chain_run);
514 515 516
		}

		for(int target = 0; target < chain_len_; target++) {
Lukas Weber's avatar
Lukas Weber committed
517
			int target_rank = rank_section * chain_len_ + target + 1;
518
			int pos = chain_run.rank_to_pos[target];
519
			// keep consistent with pt_global_update
520
			int partner_pos = pos + (2 * (pos & 1) - 1) * (2 * chain_run.swap_odd - 1);
521 522
			if(partner_pos < 0 || partner_pos >= chain_len_) {
				int response = GA_SKIP;
523
				MPI_Send(&response, 1, MPI_INT, target_rank, 0, MPI_COMM_WORLD);
Lukas Weber's avatar
Lukas Weber committed
524
				chain_run.weight_ratios[pos] = 1;
525 526
			} else {
				int response = GA_CALC_WEIGHT;
527
				MPI_Send(&response, 1, MPI_INT, target_rank, 0, MPI_COMM_WORLD);
528

529 530 531 532
				double partner_param = chain.params[partner_pos];
				MPI_Send(&partner_param, 1, MPI_DOUBLE, target_rank, 0, MPI_COMM_WORLD);
			}
		}
533

534
		for(int target = 0; target < chain_len_; target++) {
Lukas Weber's avatar
Lukas Weber committed
535
			int target_rank = rank_section * chain_len_ + target + 1;
536 537
			int pos = chain_run.rank_to_pos[target];
			if(chain_run.weight_ratios[pos] < 0) {
538
				double weight;
539
				MPI_Recv(&weight, 1, MPI_DOUBLE, target_rank, 0, MPI_COMM_WORLD, &stat);
Lukas Weber's avatar
Lukas Weber committed
540
				chain_run.weight_ratios[pos] = weight;
541
			}
542
		}
543

544 545 546 547 548
		pt_global_update(chain, chain_run);
		std::fill(chain_run.weight_ratios.begin(), chain_run.weight_ratios.end(), -1);

		for(int target = 0; target < chain_len_; target++) {
			int new_task_id = chain.task_ids[chain_run.rank_to_pos[target]];
Lukas Weber's avatar
Lukas Weber committed
549
			int partner_rank = rank_section * chain_len_ + chain_run.switch_partners[target] + 1;
550
			int msg[2] = {new_task_id, partner_rank};
Lukas Weber's avatar
Lukas Weber committed
551 552
			MPI_Send(msg, sizeof(msg) / sizeof(msg[0]), MPI_INT,
			         rank_section * chain_len_ + target + 1, 0, MPI_COMM_WORLD);
553
			double new_param = chain.params[chain_run.rank_to_pos[target]];
Lukas Weber's avatar
Lukas Weber committed
554 555
			MPI_Send(&new_param, 1, MPI_DOUBLE, rank_section * chain_len_ + target + 1, 0,
			         MPI_COMM_WORLD);
556 557 558 559 560 561 562
		}
	} else { // S_TIMEUP
		num_active_ranks_--;
	}
}

void runner_pt_master::pt_global_update(pt_chain &chain, pt_chain_run &chain_run) {
563
	int i = 0;
Lukas Weber's avatar
Lukas Weber committed
564
	for(auto &p : chain_run.switch_partners) {
565 566 567
		p = i++;
	}
	for(int i = chain_run.swap_odd; i < static_cast<int>(chain.task_ids.size()) - 1; i += 2) {
568
		double w1 = chain_run.weight_ratios[i];
569
		double w2 = chain_run.weight_ratios[i + 1];
570

571
		double p = std::min(exp(w1+w2),1.);
572 573
		double r = rng_->random_double();

574 575
		chain.rejection_rates[i] += 1 - p;
		if(r < p) {
576 577 578 579
			int rank0{};
			int rank1{};

			int rank = 0;
580
			for(auto &p : chain_run.rank_to_pos) {
Lukas Weber's avatar
Lukas Weber committed
581
				if(p == i) {
582
					rank0 = rank;
Lukas Weber's avatar
Lukas Weber committed
583
				} else if(p == i + 1) {
584
					rank1 = rank;
Lukas Weber's avatar
Lukas Weber committed
585
				}
586
				rank++;
Lukas Weber's avatar
Lukas Weber committed
587
			}
Lukas Weber's avatar
Lukas Weber committed
588
			chain_run.rank_to_pos[rank0] = i + 1;
589 590 591 592
			chain_run.rank_to_pos[rank1] = i;

			chain_run.switch_partners[rank0] = rank1;
			chain_run.switch_partners[rank1] = rank0;
593 594 595
		}
	}

596
	chain.rejection_rate_entries[chain_run.swap_odd]++;
597
	chain_run.swap_odd = !chain_run.swap_odd;
598 599 600 601 602 603 604 605 606 607
}

runner_pt_slave::runner_pt_slave(jobinfo job, mc_factory mccreator)
    : job_{std::move(job)}, mccreator_{std::move(mccreator)} {}

void runner_pt_slave::start() {
	MPI_Comm_rank(MPI_COMM_WORLD, &rank_);
	time_start_ = MPI_Wtime();
	time_last_checkpoint_ = time_start_;

608
	int group_idx;
Lukas Weber's avatar
Lukas Weber committed
609
	MPI_Scatter(NULL, 1, MPI_INT, &group_idx, 1, MPI_INT, MASTER, MPI_COMM_WORLD);
610
	MPI_Comm_split(MPI_COMM_WORLD, group_idx, 0, &chain_comm_);
Lukas Weber's avatar
Lukas Weber committed
611

612 613
	MPI_Comm_rank(chain_comm_, &chain_rank_);

Lukas Weber's avatar
Lukas Weber committed
614
	bool use_param_optimization =
615
	    job_.jobfile["jobconfig"].defined("pt_parameter_optimization");
616

617 618 619 620 621 622
	if(!accept_new_chain()) {
		return;
	}

	int action{};
	do {
623 624
		int timeout{TR_CHECKPOINT};

625 626 627
		while(sweeps_since_last_query_ < sweeps_before_communication_) {
			sys_->_do_update();

628
			if(sys_->is_thermalized() && !use_param_optimization) {
629 630 631 632 633
				sys_->_do_measurement();
			}

			if(sys_->sweep() % sweeps_per_global_update_ == 0) {
				pt_global_update();
634
				sweeps_since_last_query_++;
635

636 637 638 639
				timeout = negotiate_timeout();
				if(timeout != TR_CONTINUE) {
					break;
				}
640 641
			}
		}
642

643 644
		checkpoint_write();

645
		if(timeout == TR_TIMEUP) {
646
			send_status(S_TIMEUP);
647 648
			job_.log(fmt::format("rank {} exits: walltime up (safety interval = {} s)", rank_,
			                     sys_->safe_exit_interval()));
649 650 651 652 653 654 655 656 657 658 659
			break;
		}
		action = what_is_next(S_BUSY);
	} while(action != A_EXIT);

	if(action == A_EXIT) {
		job_.log(fmt::format("rank {} exits: out of work", rank_));
	}
}

void runner_pt_slave::send_status(int status) {
660
	MPI_Send(&status, 1, MPI_INT, MASTER, 0, MPI_COMM_WORLD);
661 662
}

663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685
int runner_pt_slave::negotiate_timeout() {
	double safe_interval = 0, max_safe_interval = 0;
	if(sys_ != nullptr) {
		safe_interval = sys_->safe_exit_interval();
	}

	MPI_Reduce(&safe_interval, &max_safe_interval, 1, MPI_DOUBLE, MPI_MAX, 0, chain_comm_);

	int result = TR_CONTINUE;
	if(chain_rank_ == 0) {
		if(MPI_Wtime() - time_last_checkpoint_ > job_.checkpoint_time) {
			result = TR_CHECKPOINT;
		}

		if(MPI_Wtime() - time_start_ > job_.walltime - max_safe_interval) {
			result = TR_TIMEUP;
		}
	}

	MPI_Bcast(&result, 1, MPI_INT, 0, chain_comm_);
	return result;
}

686
void runner_pt_slave::pt_global_update() {
687 688 689
	if(chain_rank_ == 0) {
		send_status(S_READY_FOR_GLOBAL);
	}
690 691

	int response;
692
	MPI_Recv(&response, 1, MPI_INT, MASTER, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
Lukas Weber's avatar
Lukas Weber committed
693
	// job_.log(fmt::format(" * rank {}: ready for global update", rank_));
694

Lukas Weber's avatar
Lukas Weber committed
695 696
	const std::string &param_name =
	    job_.jobfile["jobconfig"].get<std::string>("parallel_tempering_parameter");
697

698
	if(response == GA_CALC_WEIGHT) {
699
		double partner_param;
700
		MPI_Recv(&partner_param, 1, MPI_DOUBLE, MASTER, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
701
		double weight_ratio = sys_->_pt_weight_ratio(param_name, partner_param);
702
		MPI_Send(&weight_ratio, 1, MPI_DOUBLE, MASTER, 0, MPI_COMM_WORLD);
Lukas Weber's avatar
Lukas Weber committed
703
		// job_.log(fmt::format(" * rank {}: weight sent", rank_));
704
	} else {
Lukas Weber's avatar
Lukas Weber committed
705
		// job_.log(fmt::format(" * rank {}: no weight needed", rank_));
706
	}
707
	MPI_Barrier(chain_comm_);
708 709 710

	// this may be a long wait

711
	int msg[2];
Lukas Weber's avatar
Lukas Weber committed
712 713
	MPI_Recv(&msg, sizeof(msg) / sizeof(msg[0]), MPI_INT, MASTER, 0, MPI_COMM_WORLD,
	         MPI_STATUS_IGNORE);
714 715
	int new_task_id = msg[0];
	int target_rank = msg[1];
Lukas Weber's avatar
Lukas Weber committed
716

717
	double new_param;
718 719 720 721
	MPI_Recv(&new_param, 1, MPI_DOUBLE, MASTER, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);

	if(new_task_id != task_id_ || current_param_ != new_param) {
		task_id_ = new_task_id;
Lukas Weber's avatar
Lukas Weber committed
722 723
		sweeps_per_global_update_ = job_.jobfile["tasks"][job_.task_names[task_id_]].get<int>(
		    "pt_sweeps_per_global_update");
724
		sys_->_pt_update_param(target_rank, param_name, new_param);
725 726
	}
	current_param_ = new_param;
727 728 729 730
}

bool runner_pt_slave::accept_new_chain() {
	int msg[3];
731
	MPI_Recv(&msg, sizeof(msg) / sizeof(msg[0]), MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
732 733 734 735 736 737 738 739
	task_id_ = msg[0];
	run_id_ = msg[1];
	sweeps_before_communication_ = msg[2];

	if(task_id_ < 0) {
		return false;
	}

740 741
	sweeps_per_global_update_ =
	    job_.jobfile["tasks"][job_.task_names[task_id_]].get<int>("pt_sweeps_per_global_update");
742

743
	sys_ = std::unique_ptr<mc>{mccreator_(job_.jobfile["tasks"][job_.task_names[task_id_]])};
744
	sys_->pt_mode_ = true;
745 746 747 748 749 750 751 752 753 754 755 756
	if(!sys_->_read(job_.rundir(task_id_, run_id_))) {
		sys_->_init();
		job_.log(fmt::format("* initialized {}", job_.rundir(task_id_, run_id_)));
		checkpoint_write();
	} else {
		job_.log(fmt::format("* read {}", job_.rundir(task_id_, run_id_)));
	}

	return true;
}

int runner_pt_slave::what_is_next(int status) {
757 758
	if(chain_rank_ == 0) {
		send_status(status);
759

760 761 762
		int msg[1] = {sweeps_since_last_query_};
		MPI_Send(msg, sizeof(msg) / sizeof(msg[0]), MPI_INT, 0, 0, MPI_COMM_WORLD);
	}
763 764
	sweeps_since_last_query_ = 0;
	int new_action = recv_action();
765

766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784
	if(new_action == A_EXIT) {
		return A_EXIT;
	}

	if(new_action != A_CONTINUE) {
		if(new_action == A_PROCESS_DATA_NEW_JOB) {
			merge_measurements();
		}

		if(!accept_new_chain()) {
			return A_EXIT;
		}
	}
	return A_CONTINUE;
}

void runner_pt_slave::checkpoint_write() {
	time_last_checkpoint_ = MPI_Wtime();
	sys_->_write(job_.rundir(task_id_, run_id_));
Lukas Weber's avatar
Lukas Weber committed
785
	job_.log(fmt::format("* rank {}: checkpoint {}", rank_, job_.rundir(task_id_, run_id_)));
786 787 788
}

void runner_pt_master::send_action(int action, int destination) {
789
	MPI_Send(&action, 1, MPI_INT, destination, 0, MPI_COMM_WORLD);
790 791 792 793
}

int runner_pt_slave::recv_action() {
	int new_action;
794
	MPI_Recv(&new_action, 1, MPI_INT, MASTER, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
795 796 797 798 799 800 801 802
	return new_action;
}

void runner_pt_slave::merge_measurements() {
	std::string unique_filename = job_.taskdir(task_id_);
	sys_->_write_output(unique_filename);

	std::vector<evalable> evalables;
803
	if(job_.jobfile["jobconfig"].defined("pt_parameter_optimization")) {
804 805 806 807 808 809
		if(rank_ == 1) {
			job_.log("Running in parameter optimization mode. No evalables are calculated.");
		}
	} else {
		sys_->register_evalables(evalables);
	}
810 811 812 813
	job_.merge_task(task_id_, evalables);
}

}