Make if_else accesible from root

Author: Dhruvanshu-Joshi

pytensor/__init__.py

@@ -159,6 +159,7 @@ def get_underlying_scalar_constant(v):
 # isort: off
 import pytensor.tensor.random.var
 import pytensor.sparse
+from pytensor.ifelse import ifelse
 from pytensor.scan import checkpoints
 from pytensor.scan.basic import scan
 from pytensor.scan.views import foldl, foldr, map, reduce

pytensor/tensor/random/basic.py

@@ -526,6 +526,10 @@ def chisquare(df, size=None, **kwargs):
     return gamma(shape=df / 2.0, scale=2.0, size=size, **kwargs)
 
 
+def rayleigh(scale=1.0, *, size=None, **kwargs):
+    return chisquare(df=2, size=size, **kwargs) * as_tensor_variable(scale)
+
+
 class ParetoRV(ScipyRandomVariable):
     r"""A pareto continuous random variable.
 

tests/tensor/random/test_basic.py

@@ -50,6 +50,7 @@
     permutation,
     poisson,
     randint,
+    rayleigh,
     standard_normal,
     t,
     triangular,
@@ -390,6 +391,18 @@ def test_chisquare_samples(df, size):
     compare_sample_values(chisquare, df, size=size, test_fn=fixed_scipy_rvs("chi2"))
 
 
+@pytest.mark.parametrize(
+    "size",
+    [
+        (None),
+        ([]),
+    ],
+)
+def test_rayleigh_samples(size):
+    compare_sample_values(rayleigh, size=size, test_fn=fixed_scipy_rvs("rayleigh"))
+    compare_sample_values(rayleigh)
+
+
 @pytest.mark.parametrize(
     "mu, beta, size",
     [