Fix reparameterized gp.TP chi2 variable name (#3945)

* reparameterized TP chi2 parameter has unique name now

* also fix TP chi2 name in tests

* remove path that somehow got to top of file...

Author: bwengals

Diff for: pymc3/gp/gp.py

@@ -266,7 +266,7 @@ def _build_prior(self, name, X, reparameterize=True, **kwargs):
         cov = stabilize(self.cov_func(X))
         shape = infer_shape(X, kwargs.pop("shape", None))
         if reparameterize:
-            chi2 = pm.ChiSquared("chi2_", self.nu)
+            chi2 = pm.ChiSquared(name + "_chi2_", self.nu)
             v = pm.Normal(name + "_rotated_", mu=0.0, sigma=1.0, shape=shape, **kwargs)
             f = pm.Deterministic(name, (tt.sqrt(self.nu) / chi2) * (mu + cholesky(cov).dot(v)))
         else:

Diff for: pymc3/tests/test_gp.py

@@ -1015,8 +1015,8 @@ def testTPvsLatentReparameterized(self):
             p = tp.conditional("p", self.Xnew)
         chol = np.linalg.cholesky(cov_func(self.X).eval())
         y_rotated = np.linalg.solve(chol, self.y)
-        # testing full model logp unreliable due to introduction of chi2__log__
-        plogp = p.logp({"f_rotated_": y_rotated, "p": self.pnew, "chi2__log__": np.log(1e20)})
+        # testing full model logp unreliable due to introduction of f_chi2__log__
+        plogp = p.logp({"f_rotated_": y_rotated, "p": self.pnew, "f_chi2__log__": np.log(1e20)})
         npt.assert_allclose(self.plogp, plogp, atol=0, rtol=1e-2)
 
     def testAdditiveTPRaises(self):