Removal of Algorithm classes. (#657)

* more

* removing export

* removal of classes, tests passing

* linter

* fix on test

* linter

* removing parametrization on test

* code review updates

* exporting as_top_level_api in dynamic_hmc

* linter

* code review update: replace imports

blackjax/__init__.py

@@ -1,71 +1,163 @@
+import dataclasses
+from typing import Callable
+
 from blackjax._version import __version__
 
 from .adaptation.chees_adaptation import chees_adaptation
 from .adaptation.mclmc_adaptation import mclmc_find_L_and_step_size
 from .adaptation.meads_adaptation import meads_adaptation
 from .adaptation.pathfinder_adaptation import pathfinder_adaptation
 from .adaptation.window_adaptation import window_adaptation
+from .base import SamplingAlgorithm, VIAlgorithm
 from .diagnostics import effective_sample_size as ess
 from .diagnostics import potential_scale_reduction as rhat
-from .mcmc.barker import barker_proposal
-from .mcmc.dynamic_hmc import dynamic_hmc
-from .mcmc.elliptical_slice import elliptical_slice
-from .mcmc.ghmc import ghmc
-from .mcmc.hmc import hmc
-from .mcmc.mala import mala
-from .mcmc.marginal_latent_gaussian import mgrad_gaussian
-from .mcmc.mclmc import mclmc
-from .mcmc.nuts import nuts
-from .mcmc.periodic_orbital import orbital_hmc
-from .mcmc.random_walk import additive_step_random_walk, irmh, rmh
-from .mcmc.rmhmc import rmhmc
+from .mcmc import barker
+from .mcmc import dynamic_hmc as _dynamic_hmc
+from .mcmc import elliptical_slice as _elliptical_slice
+from .mcmc import ghmc as _ghmc
+from .mcmc import hmc as _hmc
+from .mcmc import mala as _mala
+from .mcmc import marginal_latent_gaussian
+from .mcmc import mclmc as _mclmc
+from .mcmc import nuts as _nuts
+from .mcmc import periodic_orbital, random_walk
+from .mcmc import rmhmc as _rmhmc
+from .mcmc.random_walk import additive_step_random_walk as _additive_step_random_walk
+from .mcmc.random_walk import (
+    irmh_as_top_level_api,
+    normal_random_walk,
+    rmh_as_top_level_api,
+)
 from .optimizers import dual_averaging, lbfgs
-from .sgmcmc.csgld import csgld
-from .sgmcmc.sghmc import sghmc
-from .sgmcmc.sgld import sgld
-from .sgmcmc.sgnht import sgnht
-from .smc.adaptive_tempered import adaptive_tempered_smc
-from .smc.inner_kernel_tuning import inner_kernel_tuning
-from .smc.tempered import tempered_smc
-from .vi.meanfield_vi import meanfield_vi
-from .vi.pathfinder import pathfinder
-from .vi.schrodinger_follmer import schrodinger_follmer
-from .vi.svgd import svgd
+from .sgmcmc import csgld as _csgld
+from .sgmcmc import sghmc as _sghmc
+from .sgmcmc import sgld as _sgld
+from .sgmcmc import sgnht as _sgnht
+from .smc import adaptive_tempered
+from .smc import inner_kernel_tuning as _inner_kernel_tuning
+from .smc import tempered
+from .vi import meanfield_vi as _meanfield_vi
+from .vi import pathfinder as _pathfinder
+from .vi import schrodinger_follmer as _schrodinger_follmer
+from .vi import svgd as _svgd
+from .vi.pathfinder import PathFinderAlgorithm
+
+"""
+The above three classes exist as a backwards compatible way of exposing both the high level, differentiable
+factory and the low level components, which may not be differentiable. Moreover, this design allows for the lower
+level to be mostly functional programming in nature and reducing boilerplate code.
+"""
+
+
+@dataclasses.dataclass
+class GenerateSamplingAPI:
+    differentiable: Callable
+    init: Callable
+    build_kernel: Callable
+
+    def __call__(self, *args, **kwargs) -> SamplingAlgorithm:
+        return self.differentiable(*args, **kwargs)
+
+    def register_factory(self, name, callable):
+        setattr(self, name, callable)
+
+
+@dataclasses.dataclass
+class GenerateVariationalAPI:
+    differentiable: Callable
+    init: Callable
+    step: Callable
+    sample: Callable
+
+    def __call__(self, *args, **kwargs) -> VIAlgorithm:
+        return self.differentiable(*args, **kwargs)
+
+
+@dataclasses.dataclass
+class GeneratePathfinderAPI:
+    differentiable: Callable
+    approximate: Callable
+    sample: Callable
+
+    def __call__(self, *args, **kwargs) -> PathFinderAlgorithm:
+        return self.differentiable(*args, **kwargs)
+
+
+def generate_top_level_api_from(module):
+    return GenerateSamplingAPI(
+        module.as_top_level_api, module.init, module.build_kernel
+    )
+
+
+# MCMC
+hmc = generate_top_level_api_from(_hmc)
+nuts = generate_top_level_api_from(_nuts)
+rmh = GenerateSamplingAPI(rmh_as_top_level_api, random_walk.init, random_walk.build_rmh)
+irmh = GenerateSamplingAPI(
+    irmh_as_top_level_api, random_walk.init, random_walk.build_irmh
+)
+dynamic_hmc = generate_top_level_api_from(_dynamic_hmc)
+rmhmc = generate_top_level_api_from(_rmhmc)
+mala = generate_top_level_api_from(_mala)
+mgrad_gaussian = generate_top_level_api_from(marginal_latent_gaussian)
+orbital_hmc = generate_top_level_api_from(periodic_orbital)
+
+additive_step_random_walk = GenerateSamplingAPI(
+    _additive_step_random_walk, random_walk.init, random_walk.build_additive_step
+)
+
+additive_step_random_walk.register_factory("normal_random_walk", normal_random_walk)
+
+mclmc = generate_top_level_api_from(_mclmc)
+elliptical_slice = generate_top_level_api_from(_elliptical_slice)
+ghmc = generate_top_level_api_from(_ghmc)
+barker_proposal = generate_top_level_api_from(barker)
+
+hmc_family = [hmc, nuts]
+
+# SMC
+adaptive_tempered_smc = generate_top_level_api_from(adaptive_tempered)
+tempered_smc = generate_top_level_api_from(tempered)
+inner_kernel_tuning = generate_top_level_api_from(_inner_kernel_tuning)
+
+smc_family = [tempered_smc, adaptive_tempered_smc]
+"Step_fn returning state has a .particles attribute"
+
+# stochastic gradient mcmc
+sgld = generate_top_level_api_from(_sgld)
+sghmc = generate_top_level_api_from(_sghmc)
+sgnht = generate_top_level_api_from(_sgnht)
+csgld = generate_top_level_api_from(_csgld)
+svgd = generate_top_level_api_from(_svgd)
+
+# variational inference
+meanfield_vi = GenerateVariationalAPI(
+    _meanfield_vi.as_top_level_api,
+    _meanfield_vi.init,
+    _meanfield_vi.step,
+    _meanfield_vi.sample,
+)
+schrodinger_follmer = GenerateVariationalAPI(
+    _schrodinger_follmer.as_top_level_api,
+    _schrodinger_follmer.init,
+    _schrodinger_follmer.step,
+    _schrodinger_follmer.sample,
+)
+
+pathfinder = GeneratePathfinderAPI(
+    _pathfinder.as_top_level_api, _pathfinder.approximate, _pathfinder.sample
+)
+
 
 __all__ = [
     "__version__",
     "dual_averaging",  # optimizers
     "lbfgs",
-    "hmc",  # mcmc
-    "dynamic_hmc",
-    "rmhmc",
-    "mala",
-    "mgrad_gaussian",
-    "nuts",
-    "orbital_hmc",
-    "additive_step_random_walk",
-    "rmh",
-    "irmh",
-    "mclmc",
-    "elliptical_slice",
-    "ghmc",
-    "barker_proposal",
-    "sgld",  # stochastic gradient mcmc
-    "sghmc",
-    "sgnht",
-    "csgld",
     "window_adaptation",  # mcmc adaptation
     "meads_adaptation",
     "chees_adaptation",
     "pathfinder_adaptation",
     "mclmc_find_L_and_step_size",  # mclmc adaptation
-    "adaptive_tempered_smc",  # smc
-    "tempered_smc",
-    "inner_kernel_tuning",
-    "meanfield_vi",  # variational inference
-    "pathfinder",
-    "schrodinger_follmer",
-    "svgd",
     "ess",  # diagnostics
     "rhat",
 ]

blackjax/adaptation/pathfinder_adaptation.py

@@ -12,12 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Implementation of the Pathinder warmup for the HMC family of sampling algorithms."""
-from typing import Callable, NamedTuple, Union
+from typing import Callable, NamedTuple
 
 import jax
 import jax.numpy as jnp
 
-import blackjax.mcmc as mcmc
 import blackjax.vi as vi
 from blackjax.adaptation.base import AdaptationInfo, AdaptationResults
 from blackjax.adaptation.step_size import (
@@ -138,7 +137,7 @@ def final(warmup_state: PathfinderAdaptationState) -> tuple[float, Array]:
 
 
 def pathfinder_adaptation(
-    algorithm: Union[mcmc.hmc.hmc, mcmc.nuts.nuts],
+    algorithm,
     logdensity_fn: Callable,
     initial_step_size: float = 1.0,
     target_acceptance_rate: float = 0.80,

blackjax/adaptation/window_adaptation.py

@@ -12,12 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """Implementation of the Stan warmup for the HMC family of sampling algorithms."""
-from typing import Callable, NamedTuple, Union
+from typing import Callable, NamedTuple
 
 import jax
 import jax.numpy as jnp
 
-import blackjax.mcmc as mcmc
 from blackjax.adaptation.base import AdaptationInfo, AdaptationResults
 from blackjax.adaptation.mass_matrix import (
     MassMatrixAdaptationState,
@@ -243,7 +242,7 @@ def final(warmup_state: WindowAdaptationState) -> tuple[float, Array]:
 
 
 def window_adaptation(
-    algorithm: Union[mcmc.hmc.hmc, mcmc.nuts.nuts],
+    algorithm,
     logdensity_fn: Callable,
     is_mass_matrix_diagonal: bool = True,
     initial_step_size: float = 1.0,
@@ -252,7 +251,7 @@ def window_adaptation(
     **extra_parameters,
 ) -> AdaptationAlgorithm:
     """Adapt the value of the inverse mass matrix and step size parameters of
-    algorithms in the HMC fmaily.
+    algorithms in the HMC family.  See Blackjax.hmc_family
 
     Algorithms in the HMC family on a euclidean manifold depend on the value of
     at least two parameters: the step size, related to the trajectory

blackjax/mcmc/barker.py

@@ -24,7 +24,7 @@
 from blackjax.mcmc.proposal import static_binomial_sampling
 from blackjax.types import ArrayLikeTree, ArrayTree, PRNGKey
 
-__all__ = ["BarkerState", "BarkerInfo", "init", "build_kernel", "barker_proposal"]
+__all__ = ["BarkerState", "BarkerInfo", "init", "build_kernel", "as_top_level_api"]
 
 
 class BarkerState(NamedTuple):
@@ -128,7 +128,10 @@ def kernel(
     return kernel
 
 
-class barker_proposal:
+def as_top_level_api(
+    logdensity_fn: Callable,
+    step_size: float,
+) -> SamplingAlgorithm:
     """Implements the (basic) user interface for the Barker's proposal :cite:p:`Livingstone2022Barker` kernel with a
     Gaussian base kernel.
 
@@ -179,24 +182,16 @@ class barker_proposal:
 
     """
 
-    init = staticmethod(init)
-    build_kernel = staticmethod(build_kernel)
+    kernel = build_kernel()
 
-    def __new__(  # type: ignore[misc]
-        cls,
-        logdensity_fn: Callable,
-        step_size: float,
-    ) -> SamplingAlgorithm:
-        kernel = cls.build_kernel()
+    def init_fn(position: ArrayLikeTree, rng_key=None):
+        del rng_key
+        return init(position, logdensity_fn)
 
-        def init_fn(position: ArrayLikeTree, rng_key=None):
-            del rng_key
-            return cls.init(position, logdensity_fn)
+    def step_fn(rng_key: PRNGKey, state):
+        return kernel(rng_key, state, logdensity_fn, step_size)
 
-        def step_fn(rng_key: PRNGKey, state):
-            return kernel(rng_key, state, logdensity_fn, step_size)
-
-        return SamplingAlgorithm(init_fn, step_fn)
+    return SamplingAlgorithm(init_fn, step_fn)
 
 
 def _barker_sample_nd(key, mean, a, scale):