Remove unused merge_traces helper function

Author: michaelosthege

pymc/backends/base.py

@@ -21,12 +21,11 @@
 import warnings
 
 from abc import ABC
-from typing import List
 
 import aesara.tensor as at
 import numpy as np
 
-from pymc.backends.report import SamplerReport, merge_reports
+from pymc.backends.report import SamplerReport
 from pymc.model import modelcontext
 from pymc.util import get_var_name
 
@@ -570,43 +569,6 @@ def points(self, chains=None):
         return itl.chain.from_iterable(self._straces[chain] for chain in chains)
 
 
-def merge_traces(mtraces: List[MultiTrace]) -> MultiTrace:
-    """Merge MultiTrace objects.
-
-    Parameters
-    ----------
-    mtraces: list of MultiTraces
-        Each instance should have unique chain numbers.
-
-    Raises
-    ------
-    A ValueError is raised if any traces have overlapping chain numbers,
-    or if chains are of different lengths.
-
-    Returns
-    -------
-    A MultiTrace instance with merged chains
-    """
-    if len(mtraces) == 0:
-        raise ValueError("Cannot merge an empty set of traces.")
-    base_mtrace = mtraces[0]
-    chain_len = len(base_mtrace)
-    # check base trace
-    if any(
-        len(st) != chain_len for _, st in base_mtrace._straces.items()
-    ):  # pylint: disable=line-too-long
-        raise ValueError("Chains are of different lengths.")
-    for new_mtrace in mtraces[1:]:
-        for new_chain, strace in new_mtrace._straces.items():
-            if new_chain in base_mtrace._straces:
-                raise ValueError("Chains are not unique.")
-            if len(strace) != chain_len:
-                raise ValueError("Chains are of different lengths.")
-            base_mtrace._straces[new_chain] = strace
-    base_mtrace._report = merge_reports([trace.report for trace in mtraces])
-    return base_mtrace
-
-
 def _squeeze_cat(results, combine, squeeze):
     """Squeeze and concatenate the results depending on values of
     `combine` and `squeeze`."""

pymc/backends/report.py

@@ -206,12 +206,3 @@ def filter_warns(warnings):
             report._add_warnings(filter_warns(self._chain_warnings[chain]), chain)
 
         return report
-
-
-def merge_reports(reports):
-    report = SamplerReport()
-    for rep in reports:
-        report._add_warnings(rep._global_warnings)
-        for chain in rep._chain_warnings:
-            report._add_warnings(rep._chain_warnings[chain], chain)
-    return report

pymc/tests/backends/test_ndarray.py

@@ -123,37 +123,6 @@ def test_multitrace_nonunique(self):
         with pytest.raises(ValueError):
             base.MultiTrace([self.strace0, self.strace1])
 
-    def test_merge_traces_no_traces(self):
-        with pytest.raises(ValueError):
-            base.merge_traces([])
-
-    def test_merge_traces_diff_lengths(self):
-        with self.model:
-            strace0 = self.backend(self.name)
-            strace0.setup(self.draws, 1)
-            for i in range(self.draws):
-                strace0.record(self.test_point)
-            strace0.close()
-        mtrace0 = base.MultiTrace([self.strace0])
-
-        with self.model:
-            strace1 = self.backend(self.name)
-            strace1.setup(2 * self.draws, 1)
-            for i in range(2 * self.draws):
-                strace1.record(self.test_point)
-            strace1.close()
-        mtrace1 = base.MultiTrace([strace1])
-
-        with pytest.raises(ValueError):
-            base.merge_traces([mtrace0, mtrace1])
-
-    def test_merge_traces_nonunique(self):
-        mtrace0 = base.MultiTrace([self.strace0])
-        mtrace1 = base.MultiTrace([self.strace1])
-
-        with pytest.raises(ValueError):
-            base.merge_traces([mtrace0, mtrace1])
-
 
 class TestMultiTrace_add_remove_values(bf.ModelBackendSampledTestCase):
     name = None