Added ability for priors of transformed distributions to have their p… (

#2551)

gpytorch/priors/prior.py

@@ -1,10 +1,18 @@
 #!/usr/bin/env python3
 
 from abc import ABC
+from typing import Any, Mapping
 
+from torch.distributions import TransformedDistribution
 from torch.nn import Module
 
 from ..distributions import Distribution
+from .utils import _load_transformed_to_base_dist
+
+
+TRANSFORMED_ERROR_MSG = """Priors of TransformedDistributions should not have their \
+'_transformed' attributes modified, these are just copies of the base attribute. \
+Please modify the base attribute (e.g. {}) instead."""
 
 
 class Prior(Distribution, Module, ABC):
@@ -25,3 +33,20 @@ def log_prob(self, x):
         :rtype: torch.Tensor
         """
         return super(Prior, self).log_prob(self.transform(x))
+
+    def load_state_dict(self, state_dict: Mapping[str, Any], *args, **kwargs):
+        Module.load_state_dict(self, state_dict, *args, **kwargs)
+        if isinstance(self, TransformedDistribution):
+            _load_transformed_to_base_dist(self)
+
+    def __setattr__(self, name: str, value: Any) -> None:
+        if hasattr(self, name) and "_transformed_" in name:
+            base_attr_name = name.replace("_transformed_", "")
+            raise AttributeError(TRANSFORMED_ERROR_MSG.format(base_attr_name))
+
+        elif hasattr(self, f"_transformed_{name}"):
+            self.base_dist.__setattr__(name, value)
+            super().__setattr__(f"_transformed_{name}", value)
+
+        else:
+            return super().__setattr__(name, value)

gpytorch/priors/torch_priors.py

@@ -40,6 +40,7 @@ class HalfNormalPrior(Prior, HalfNormal):
     def __init__(self, scale, validate_args=None, transform=None):
         TModule.__init__(self)
         HalfNormal.__init__(self, scale=scale, validate_args=validate_args)
+        _bufferize_attributes(self, ("scale",))
         self._transform = transform
 
     def expand(self, batch_shape):
@@ -54,6 +55,7 @@ class LogNormalPrior(Prior, LogNormal):
     def __init__(self, loc, scale, validate_args=None, transform=None):
         TModule.__init__(self)
         LogNormal.__init__(self, loc=loc, scale=scale, validate_args=validate_args)
+        _bufferize_attributes(self, ("loc", "scale"))
         self._transform = transform
 
     def expand(self, batch_shape):
@@ -84,6 +86,7 @@ class HalfCauchyPrior(Prior, HalfCauchy):
     def __init__(self, scale, validate_args=None, transform=None):
         TModule.__init__(self)
         HalfCauchy.__init__(self, scale=scale, validate_args=validate_args)
+        _bufferize_attributes(self, ("scale",))
         self._transform = transform
 
     def expand(self, batch_shape):

gpytorch/priors/utils.py

@@ -1,11 +1,36 @@
 #!/usr/bin/env python3
 
+from torch.distributions import TransformedDistribution
+
 
 def _bufferize_attributes(module, attributes):
-    attr_clones = {attr: getattr(module, attr).clone() for attr in attributes}
-    for attr, value in attr_clones.items():
-        delattr(module, attr)
-        module.register_buffer(attr, value)
+    r"""
+    Adds the parameters of the prior as a torch buffer to enable saving/
+    loading to/from state_dicts.
+    For TransformedDistributions Adds a _transformed_ attribute to the
+    parameters. This enables its parameters to be saved and
+    loaded to/from state_dicts, as the original parameters cannot be.
+    """
+    if isinstance(module, TransformedDistribution):
+        for attr in attributes:
+            module.register_buffer(f"_transformed_{attr}", getattr(module, attr))
+    else:
+        attr_clones = {attr: getattr(module, attr).clone() for attr in attributes}
+        for attr, value in attr_clones.items():
+            delattr(module, attr)
+            module.register_buffer(attr, value)
+
+
+def _load_transformed_to_base_dist(module):
+    r"""loads the  _transformed_ attributes to the parameters of a torch
+    TransformedDistribution. This enables its parameters to be saved and
+    loaded to/from state_dicts, as the original parameters cannot be.
+    """
+    transf_str = "_transformed_"
+    transformed_attrs = [attr for attr in dir(module) if transf_str in attr]
+    for transf_attr in transformed_attrs:
+        base_attr_name = transf_attr.replace(transf_str, "")
+        setattr(module.base_dist, base_attr_name, getattr(module, transf_attr))
 
 
 def _del_attributes(module, attributes, raise_on_error=False):

test/priors/test_prior.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import unittest
+
+from torch import Tensor
+
+from gpytorch.priors import GammaPrior, HalfCauchyPrior, LogNormalPrior, NormalPrior
+
+
+TRANSFORMED_ERROR_MSG = """Priors of TransformedDistributions should not have their \
+'_transformed' attributes modified, these are just copies of the base attribute. \
+Please modify the base attribute (e.g. {}) instead."""
+
+
+class TestPrior(unittest.TestCase):
+    def test_state_dict(self):
+        normal = NormalPrior(0.1, 1).state_dict()
+        self.assertTrue("loc" in normal)
+        self.assertTrue("scale" in normal)
+        self.assertEqual(normal["loc"], 0.1)
+
+        gamma = GammaPrior(1.1, 2).state_dict()
+        self.assertTrue("concentration" in gamma)
+        self.assertTrue("rate" in gamma)
+        self.assertEqual(gamma["concentration"], 1.1)
+
+        ln = LogNormalPrior(2.1, 1.2).state_dict()
+        self.assertTrue("_transformed_loc" in ln)
+        self.assertTrue("_transformed_scale" in ln)
+        self.assertEqual(ln["_transformed_loc"], 2.1)
+
+        hc = HalfCauchyPrior(1.3).state_dict()
+        self.assertTrue("_transformed_scale" in hc)
+
+    def test_load_state_dict(self):
+        ln1 = LogNormalPrior(loc=0.5, scale=0.1)
+        ln2 = LogNormalPrior(loc=2.5, scale=2.1)
+        gm1 = GammaPrior(concentration=0.5, rate=0.1)
+        gm2 = GammaPrior(concentration=2.5, rate=2.1)
+        hc1 = HalfCauchyPrior(scale=1.1)
+        hc2 = HalfCauchyPrior(scale=101.1)
+
+        ln2.load_state_dict(ln1.state_dict())
+        self.assertEqual(ln2.loc, ln1.loc)
+        self.assertEqual(ln2.scale, ln1.scale)
+
+        gm2.load_state_dict(gm1.state_dict())
+        self.assertEqual(gm2.concentration, gm1.concentration)
+        self.assertEqual(gm2.rate, gm1.rate)
+
+        hc2.load_state_dict(hc1.state_dict())
+        self.assertEqual(hc2.scale, hc1.scale)
+
+    def test_transformed_attributes(self):
+        norm = NormalPrior(loc=2.5, scale=2.1)
+        ln = LogNormalPrior(loc=2.5, scale=2.1)
+        hc = HalfCauchyPrior(scale=2.2)
+
+        with self.assertRaisesRegex(AttributeError, "'NormalPrior' object has no attribute '_transformed_loc'"):
+            getattr(norm, "_transformed_loc")
+
+        self.assertTrue(getattr(ln, "_transformed_loc"), 2.5)
+        norm.loc = Tensor([1.01])
+        ln.loc = Tensor([1.01])
+        self.assertEqual(ln._transformed_loc, 1.01)
+        with self.assertRaises(AttributeError):
+            ln._transformed_loc = 1.1
+
+        with self.assertRaises(AttributeError):
+            hc._transformed_scale = 1.01

test/priors/test_utils.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+import unittest
+
+from torch import Tensor
+
+from gpytorch.priors import GammaPrior, HalfCauchyPrior, LogNormalPrior, NormalPrior
+
+
+class TestPrior(unittest.TestCase):
+    def test_state_dict(self):
+        normal = NormalPrior(0.1, 1).state_dict()
+        self.assertTrue("loc" in normal)
+        self.assertTrue("scale" in normal)
+        self.assertEqual(normal["loc"], 0.1)
+
+        gamma = GammaPrior(1.1, 2).state_dict()
+        self.assertTrue("concentration" in gamma)
+        self.assertTrue("rate" in gamma)
+        self.assertEqual(gamma["concentration"], 1.1)
+
+        ln = LogNormalPrior(2.1, 1.2).state_dict()
+        self.assertTrue("_transformed_loc" in ln)
+        self.assertTrue("_transformed_scale" in ln)
+        self.assertEqual(ln["_transformed_loc"], 2.1)
+
+        hc = HalfCauchyPrior(1.3).state_dict()
+        self.assertTrue("_transformed_scale" in hc)
+
+    def test_load_state_dict(self):
+        ln1 = LogNormalPrior(loc=0.5, scale=0.1)
+        ln2 = LogNormalPrior(loc=2.5, scale=2.1)
+        gm1 = GammaPrior(concentration=0.5, rate=0.1)
+        gm2 = GammaPrior(concentration=2.5, rate=2.1)
+        hc1 = HalfCauchyPrior(scale=1.1)
+        hc2 = HalfCauchyPrior(scale=101.1)
+
+        ln2.load_state_dict(ln1.state_dict())
+        self.assertEqual(ln2.loc, ln1.loc)
+        self.assertEqual(ln2.scale, ln1.scale)
+
+        gm2.load_state_dict(gm1.state_dict())
+        self.assertEqual(gm2.concentration, gm1.concentration)
+        self.assertEqual(gm2.rate, gm1.rate)
+
+        hc2.load_state_dict(hc1.state_dict())
+        self.assertEqual(hc2.scale, hc1.scale)
+
+    def test_transformed_attributes(self):
+        norm = NormalPrior(loc=2.5, scale=2.1)
+        ln = LogNormalPrior(loc=2.5, scale=2.1)
+        hc = HalfCauchyPrior(scale=2.2)
+
+        with self.assertRaisesRegex(AttributeError, "'NormalPrior' object has no attribute '_transformed_loc'"):
+            getattr(norm, "_transformed_loc")
+
+        self.assertTrue(getattr(ln, "_transformed_loc"), 2.5)
+        norm.loc = Tensor([1.01])
+        ln.loc = Tensor([1.01])
+        self.assertEqual(ln._transformed_loc, 1.01)
+        self.assertEqual(hc._transformed_scale, 2.2)