Merge branch 'minor-fixes-needed-for-ptemcee' into 'master'

Minor fixes required for stable use of ptemcee

See merge request !625

bilby/core/result.py

@@ -1361,7 +1361,7 @@ class ResultList(list):
         self.check_consistent_priors()
 
         # check which kind of sampler was used: MCMC or Nested Sampling
-        if result.nested_samples is not None:
+        if result._nested_samples is not None:
             posteriors, result = self._combine_nested_sampled_runs(result)
         else:
             posteriors = [res.posterior for res in self]

bilby/core/sampler/ptemcee.py

@@ -2,6 +2,8 @@ from __future__ import absolute_import, division, print_function
 
 import os
 from shutil import copyfile
+import signal
+import sys
 
 import numpy as np
 
@@ -47,6 +49,10 @@ class Ptemcee(Emcee):
             nburn=nburn, burn_in_fraction=burn_in_fraction,
             burn_in_act=burn_in_act, resume=resume, **kwargs)
 
+        signal.signal(signal.SIGTERM, self.write_current_state_and_exit)
+        signal.signal(signal.SIGINT, self.write_current_state_and_exit)
+        signal.signal(signal.SIGALRM, self.write_current_state_and_exit)
+
     @property
     def sampler_function_kwargs(self):
         keys = ['iterations', 'thin', 'storechain', 'adapt', 'swap_ratios']
@@ -82,7 +88,10 @@ class Ptemcee(Emcee):
         chain_file = self.checkpoint_info.chain_file
         temp_chain_file = chain_file + '.temp'
         if os.path.isfile(chain_file):
-            copyfile(chain_file, temp_chain_file)
+            try:
+                copyfile(chain_file, temp_chain_file)
+            except OSError:
+                logger.warning("Failed to write temporary chain file {}".format(temp_chain_file))
 
         with open(temp_chain_file, "a") as ff:
             loglike = np.squeeze(loglike[0, :])
@@ -92,6 +101,10 @@ class Ptemcee(Emcee):
                 ff.write(self.checkpoint_info.chain_template.format(ii, *line))
         os.rename(temp_chain_file, chain_file)
 
+    def write_current_state_and_exit(self, signum=None, frame=None):
+        logger.warning("Run terminated with signal {}".format(signum))
+        sys.exit(130)
+
     @property
     def _previous_iterations(self):
         """ Returns the number of iterations that the sampler has saved