Merge pull request #37 from chrhansk/feature-runner-time-limit

Add strict time limit to runners

docs/conf.py

@@ -14,7 +14,7 @@
 project = "pygradflow"
 copyright = "2023, Christoph Hansknecht"
 author = "Christoph Hansknecht"
-release = "0.3.7"
+release = "0.3.8"
 
 # -- General configuration ---------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration

pygradflow/runners/runner.py

@@ -1,8 +1,13 @@
 import datetime
 import enum
+import itertools
 import logging
 import os
 from abc import ABC, abstractmethod
+from multiprocessing import Pool, TimeoutError, cpu_count
+from multiprocessing.pool import ThreadPool
+
+import numpy as np
 
 from pygradflow.log import logger
 from pygradflow.params import Params
@@ -20,11 +25,28 @@ def try_solve_instance(instance, params, log_filename):
         logger.handlers.clear()
         logger.addHandler(handler)
         logger.setLevel(logging.INFO)
-        return instance.solve(params)
+
+        def solve():
+            return instance.solve(params)
+
+        # No time limit
+        if params.time_limit == np.inf:
+            return solve()
+
+        # Solve in thread pool so we can
+        # await the result
+        thread_pool = ThreadPool(1)
+
+        try:
+            res = thread_pool.apply_async(solve)
+            return res.get(params.time_limit)
+        except TimeoutError:
+            logger.error("Reached timeout, aborting")
+            return "timeout"
     except Exception as exc:
         logger.error("Error solving %s", instance.name)
         logger.exception(exc, exc_info=(type(exc), exc, exc.__traceback__))
-        return None
+        return "error"
 
 
 class Runner(ABC):
@@ -57,9 +79,6 @@ def log_filename(instance):
             return self.output_filename(args, f"{instance.name}.log")
 
         if args.parallel is not None:
-            import itertools
-            from multiprocessing import Pool, cpu_count
-
             if args.parallel is True:
                 num_procs = cpu_count()
             else:
@@ -72,7 +91,7 @@ def log_filename(instance):
 
             solve_args = zip(instances, all_params, all_log_filenames)
 
-            with Pool(num_procs) as pool:
+            with Pool(num_procs, maxtasksperchild=1) as pool:
                 results = pool.starmap(try_solve_instance, solve_args)
 
         else:
@@ -138,7 +157,9 @@ def output_filename(self, args, filename):
 
     def main(self):
         run_logger.setLevel(logging.INFO)
-        run_logger.addHandler(logging.StreamHandler())
+        handler = logging.StreamHandler()
+        handler.setFormatter(formatter)
+        run_logger.addHandler(handler)
 
         args = self.parser().parse_args()
 
@@ -184,7 +205,18 @@ def write_results(self, args, params, instances, results):
                     "size": instance.size,
                 }
 
-                if result is None:
+                if result == "timeout":
+                    writer.writerow(
+                        {
+                            **info,
+                            "status": "timeout",
+                            "total_time": args.time_limit,
+                            "iterations": 0,
+                            "num_accepted_steps": 0,
+                        }
+                    )
+
+                elif result == "error":
                     writer.writerow(
                         {
                             **info,
@@ -198,7 +230,7 @@ def write_results(self, args, params, instances, results):
                     writer.writerow(
                         {
                             **info,
-                            "status": SolverStatus.short_name(result),
+                            "status": SolverStatus.short_name(result.status),
                             "total_time": result.total_time,
                             "iterations": result.iterations,
                             "num_accepted_steps": result.num_accepted_steps,

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pygradflow"
-version = "0.3.7"
+version = "0.3.8"
 description = "PyGradFlow is a simple implementation of the sequential homotopy method to be used to solve general nonlinear programs."
 authors = ["Christoph Hansknecht <[email protected]>"]
 readme = "README.md"