change circular transform from ElemwiseTransform to Transform. add circular domain for vonmises tests (#1520)

Author: aloctavodia

pymc3/distributions/transforms.py

@@ -240,7 +240,7 @@ def jacobian_det(self, y_):
 t_stick_breaking = lambda eps: StickBreaking(eps)
 
 
-class Circular(ElemwiseTransform):
+class Circular(Transform):
     """Transforms a linear space into a circular one.
     """
     name = "circular"
@@ -250,5 +250,8 @@ def backward(self, y):
 
     def forward(self, x):
         return x
+        
+    def jacobian_det(self, x):
+        return 0
 
 circular = Circular()

pymc3/tests/test_distributions.py

@@ -90,6 +90,8 @@ def product(domains, n_samples=-1):
 Rminusbig = Domain([-inf, -2, -1.5, -1, -.99, -.9, -.5, -0.01, 0])
 Unit = Domain([0, .001, .1, .5, .75, .99, 1])
 
+Circ = Domain([-np.pi -2.1, -1, -.01, .0, .01, 1, 2.1, np.pi])
+
 Runif = Domain([-1, -.4, 0, .4, 1])
 Rdunif = Domain([-10, 0, 10.])
 Rplusunif = Domain([0, .5, inf])
@@ -678,8 +680,9 @@ def check_ex_gaussian(self, value, mu, sigma, nu, logp):
         pt = {'eg': value}
         assert_almost_equal(model.fastlogp(pt), logp, decimal=6, err_msg=str(pt))
 
+
     def test_vonmises(self):
-        self.pymc3_matches_scipy(VonMises, R, {'mu': R, 'kappa': Rplus},
+        self.pymc3_matches_scipy(VonMises, R, {'mu': Circ, 'kappa': Rplus},
                                  lambda value, mu, kappa: sp.vonmises.logpdf(value, kappa, loc=mu))
 
     def test_multidimensional_beta_construction(self):