Merge 1e87467 into 80c7acb

arviz-devs · Oct 29, 2019 · 3a1015d · 3a1015d
2 parents 80c7acb + 1e87467
commit 3a1015d
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diff --git a/arviz/data/io_emcee.py b/arviz/data/io_emcee.py
@@ -182,6 +182,8 @@ def blobs_to_dict(self):
             blobs = np.array(self.sampler.blobs)
         if blobs is None or blobs.size == 0:
             raise ValueError("No blobs in sampler, blob_names must be None")
+        if len(blobs.shape) == 2:
+            blobs = np.expand_dims(blobs, axis=-1)
         blobs = blobs.swapaxes(0, 2)
         nblobs, nwalkers, ndraws, *_ = blobs.shape
         if len(self.blob_names) != nblobs and len(self.blob_names) != 1:

diff --git a/arviz/tests/test_data_emcee.py b/arviz/tests/test_data_emcee.py
@@ -128,6 +128,13 @@ def test_peculiar_blobs(self, data):
         fails = check_multiple_attrs({"sample_stats": ["mix"]}, inference_data)
         assert not fails
 
+    def test_single_blob(self):
+        sampler = emcee.EnsembleSampler(6, 1, lambda x: (-x ** 2, 3))
+        sampler.run_mcmc(np.random.normal(size=(6, 1)), 20)
+        inference_data = from_emcee(sampler, blob_names=["blob"])
+        fails = check_multiple_attrs({"sample_stats": ["blob"]}, inference_data)
+        assert not fails
+
     @pytest.mark.parametrize(
         "blob_args",
         [