Changes the default number of walks to 30x ndim (previously 10x ndims).

CHANGELOG.md

@@ -5,7 +5,9 @@
 ### Added
 - 
 ### Changed
-- 
+- Dynesty default settings changed: by default, now uses 30xndim walks. This was
+shown (!564) to provide better convergence for the long-duration high-spin tests.
+
 ### Removed
 - 
 

bilby/core/sampler/dynesty.py

@@ -55,7 +55,7 @@ class Dynesty(NestedSampler):
         Method used to sample uniformly within the likelihood constraints,
         conditioned on the provided bounds
     walks: int
-        Number of walks taken if using `sample='rwalk'`, defaults to `ndim * 5`
+        Number of walks taken if using `sample='rwalk'`, defaults to `ndim * 30`
     dlogz: float, (0.1)
         Stopping criteria
     verbose: Bool
@@ -156,7 +156,7 @@ class Dynesty(NestedSampler):
 
     def _verify_kwargs_against_default_kwargs(self):
         if not self.kwargs['walks']:
-            self.kwargs['walks'] = self.ndim * 10
+            self.kwargs['walks'] = self.ndim * 30
         if not self.kwargs['update_interval']:
             self.kwargs['update_interval'] = int(0.6 * self.kwargs['nlive'])
         if not self.kwargs['print_func']:

test/sampler_test.py

@@ -5,7 +5,6 @@ import unittest
 from mock import MagicMock
 import numpy as np
 import os
-import sys
 import shutil
 import copy
 
@@ -154,14 +153,13 @@ class TestDynesty(unittest.TestCase):
                         enlarge=None, bootstrap=None, vol_dec=0.5, vol_check=2.0,
                         facc=0.5, slices=5, dlogz=0.1, maxiter=None, maxcall=None,
                         logl_max=np.inf, add_live=True, print_progress=True, save_bounds=False,
-                        walks=20, update_interval=600, print_func='func')
+                        walks=60, update_interval=600, print_func='func')
         self.sampler.kwargs['print_func'] = 'func'  # set this manually as this is not testable otherwise
         self.assertListEqual([0, 1], self.sampler.kwargs['periodic'])  # Check this separately
         self.sampler.kwargs['periodic'] = None  # The dict comparison can't handle lists
         for key in self.sampler.kwargs.keys():
-            print(key)
-            print(expected[key])
-            print(self.sampler.kwargs[key])
+            print("key={}, expected={}, actual={}"
+                  .format(key, expected[key], self.sampler.kwargs[key]))
         self.assertDictEqual(expected, self.sampler.kwargs)
 
     def test_translate_kwargs(self):
@@ -173,7 +171,7 @@ class TestDynesty(unittest.TestCase):
                         enlarge=None, bootstrap=None, vol_dec=0.5, vol_check=2.0,
                         facc=0.5, slices=5, dlogz=0.1, maxiter=None, maxcall=None,
                         logl_max=np.inf, add_live=True, print_progress=True, save_bounds=False,
-                        walks=20, update_interval=600, print_func='func')
+                        walks=60, update_interval=600, print_func='func')
 
         for equiv in bilby.core.sampler.base_sampler.NestedSampler.npoints_equiv_kwargs:
             new_kwargs = self.sampler.kwargs.copy()