From 762583b59f7d3a428ad90da75daf90d3c4b9a123 Mon Sep 17 00:00:00 2001
From: Joe Zuntz <joezuntz@googlemail.com>
Date: Thu, 9 Nov 2023 14:37:39 +0000
Subject: [PATCH 1/2] Make list sampler operate in chunks of data

---
 cosmosis/samplers/list/list_sampler.py | 53 +++++++++++++++-----------
 1 file changed, 31 insertions(+), 22 deletions(-)

diff --git a/cosmosis/samplers/list/list_sampler.py b/cosmosis/samplers/list/list_sampler.py
index 3d4337d4..c8f736d3 100755
--- a/cosmosis/samplers/list/list_sampler.py
+++ b/cosmosis/samplers/list/list_sampler.py
@@ -29,6 +29,7 @@ def config(self):
         self.burn = self.read_ini("burn", int, 0)
         self.thin = self.read_ini("thin", int, 1)
         limits = self.read_ini("limits", bool, False)
+        self.chunk_size = self.read_ini("chunk_size", int, 100)
 
         #overwrite the parameter limits
         if not limits:
@@ -93,28 +94,36 @@ def execute(self):
         sample_index = list(range(len(sample_vectors)))
         jobs = list(zip(sample_index, sample_vectors))
 
-        #Run all the parameters
-        #This only outputs them all at the end
-        #which is a bit problematic, though you 
-        #can't use MPI and retain the output ordering.
-        #Have a few options depending on whether
-        #you care about this we should think about
-        #(also true for grid sampler).
-        if self.pool:
-            results = self.pool.map(task, jobs)
-        else:
-            results = list(map(task, jobs))
-
-        #Save the results of the sampling
-        #We now need to abuse the output code a little.
-        for sample, result  in zip(sample_vectors, results):
-            #Optionally save all the results calculated by each
-            #pipeline run to files
-            (prob, (prior,extra)) = result
-            #always save the usual text output
-            self.output.parameters(sample, extra, prior, prob)
-        #We only ever run this once, though that could 
-        #change if we decide to split up the runs
+        nsample = len(sample_index)
+        nchunk = nsample//self.chunk_size
+        if nsample%self.chunk_size!=0:
+            nchunk += 1
+        
+        # Run on a chunk of parameters
+        for i in range(nchunk):
+            start = i*self.chunk_size
+            end = (i+1)*self.chunk_size
+            if end>nsample:
+                end = nsample
+            chunk = jobs[start:end]
+
+            if self.pool:
+                results = self.pool.map(task, chunk)
+            else:
+                results = list(map(task, chunk))
+
+
+            # Save the results of the sampling
+            # We now need to abuse the output code a little.
+            for sample, result  in zip(sample_vectors[start:end], results):
+                # Optionally save all the results calculated by each
+                # pipeline run to files
+                (prob, (prior,extra)) = result
+                # always save the usual text output
+                self.output.parameters(sample, extra, prior, prob)
+
+        # We only ever run this once, though that could 
+        # change if we decide to split up the runs
         self.converged = True
 
     def is_converged(self):

From 5d274ba2e1601e9d168bd120718a329b4a155f02 Mon Sep 17 00:00:00 2001
From: joezuntz <joezuntz@googlemail.com>
Date: Thu, 9 Nov 2023 14:52:00 +0000
Subject: [PATCH 2/2] Update version.py

---
 cosmosis/version.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cosmosis/version.py b/cosmosis/version.py
index 36f77735..daee014f 100644
--- a/cosmosis/version.py
+++ b/cosmosis/version.py
@@ -1 +1 @@
-__version__ = '3.4'
+__version__ = '3.4.2'