Fix issue 3793 (#3843)

* Demonstrate issue 3793.

* Give Data model-relative names.

Use Model.name_for() to relativize pm.Data names.

* Move test description into docstring

* mention changes to pm.Data naming

closes #3793

Co-authored-by: michaelosthege <thecakedev@hotmail.com>

RELEASE-NOTES.md

@@ -14,6 +14,7 @@
 - Remove `sample_ppc` and `sample_ppc_w` that were deprecated in 3.6.
 - Tuning results no longer leak into sequentially sampled `Metropolis` chains (see #3733 and #3796).
 - Deprecated `sd` in version 3.7 has been replaced by `sigma` now raises `DepreciationWarning` on using `sd` in continuous, mixed and timeseries distributions. (see #3837 and #3688).
+- In named models, `pm.Data` objects now get model-relative names (see [#3843](https://github.com/pymc-devs/pymc3/pull/3843))
 
 ## PyMC3 3.8 (November 29 2019)
 

pymc3/data.py

@@ -479,13 +479,6 @@ class Data:
     https://docs.pymc.io/notebooks/data_container.html
     """
     def __new__(self, name, value):
-        # `pm.model.pandas_to_array` takes care of parameter `value` and
-        # transforms it to something digestible for pymc3
-        shared_object = theano.shared(pm.model.pandas_to_array(value), name)
-
-        # To draw the node for this variable in the graphviz Digraph we need
-        # its shape.
-        shared_object.dshape = tuple(shared_object.shape.eval())
 
         # Add data container to the named variables of the model.
         try:
@@ -494,6 +487,18 @@ def __new__(self, name, value):
             raise TypeError("No model on context stack, which is needed to "
                             "instantiate a data container. Add variable "
                             "inside a 'with model:' block.")
+
+        name = model.name_for(name)
+
+        # `pm.model.pandas_to_array` takes care of parameter `value` and
+        # transforms it to something digestible for pymc3
+        shared_object = theano.shared(pm.model.pandas_to_array(value), name)
+
+        # To draw the node for this variable in the graphviz Digraph we need
+        # its shape.
+        shared_object.dshape = tuple(shared_object.shape.eval())
+
+
         model.add_random_variable(shared_object)
 
         return shared_object

pymc3/tests/test_data_container.py

@@ -143,3 +143,15 @@ def test_model_to_graphviz_for_model_with_data_container(self):
         assert text in g.source
         text = 'obs [label="obs ~ Normal" style=filled]'
         assert text in g.source
+
+
+def test_data_naming():
+    """
+    This is a test for issue #3793 -- `Data` objects in named models are 
+    not given model-relative names.
+    """
+    with pm.Model("named_model") as model:
+        x = pm.Data("x", [1.0, 2.0, 3.0])
+        y = pm.Normal("y")
+    assert y.name == "named_model_y"
+    assert x.name == "named_model_x"