Source code for pymc.data

#   Copyright 2024 The PyMC Developers
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

import io
import urllib.request
import warnings

from collections.abc import Sequence
from copy import copy
from typing import cast

import numpy as np
import pandas as pd
import pytensor
import pytensor.tensor as pt
import xarray as xr

from pytensor.compile.builders import OpFromGraph
from pytensor.compile.sharedvalue import SharedVariable
from pytensor.graph.basic import Variable
from pytensor.raise_op import Assert
from pytensor.scalar import Cast
from pytensor.tensor.elemwise import Elemwise
from pytensor.tensor.random.basic import IntegersRV
from pytensor.tensor.type import TensorType
from pytensor.tensor.variable import TensorConstant, TensorVariable

import pymc as pm

from pymc.pytensorf import GeneratorOp, convert_data, smarttypeX
from pymc.vartypes import isgenerator

__all__ = [
    "get_data",
    "GeneratorAdapter",
    "Minibatch",
    "Data",
    "ConstantData",
    "MutableData",
]
BASE_URL = "https://raw.githubusercontent.com/pymc-devs/pymc-examples/main/examples/data/{filename}"


[docs] def get_data(filename): """Return a BytesIO object for a package data file. Parameters ---------- filename: str file to load Returns ------- BytesIO of the data """ with urllib.request.urlopen(BASE_URL.format(filename=filename)) as handle: content = handle.read() return io.BytesIO(content)
class GenTensorVariable(TensorVariable): def __init__(self, op, type, name=None): super().__init__(type=type, owner=None, name=name) self.op = op def set_gen(self, gen): self.op.set_gen(gen) def set_default(self, value): self.op.set_default(value) def clone(self): cp = self.__class__(self.op, self.type, self.name) cp.tag = copy(self.tag) return cp
[docs] class GeneratorAdapter: """Class that helps infer data type of generator. It looks at the first item, preserving the order of the resulting generator. """
[docs] def make_variable(self, gop, name=None): var = GenTensorVariable(gop, self.tensortype, name) var.tag.test_value = self.test_value return var
[docs] def __init__(self, generator): if not pm.vartypes.isgenerator(generator): raise TypeError("Object should be generator like") self.test_value = smarttypeX(copy(next(generator))) # make pickling potentially possible self._yielded_test_value = False self.gen = generator self.tensortype = TensorType(self.test_value.dtype, ((False,) * self.test_value.ndim))
# python3 generator def __next__(self): """Next value in the generator.""" if not self._yielded_test_value: self._yielded_test_value = True return self.test_value else: return smarttypeX(copy(next(self.gen))) # python2 generator next = __next__ def __iter__(self): """Return an iterator.""" return self def __eq__(self, other): """Return true if both objects are actually the same.""" return id(self) == id(other) def __hash__(self): """Return a hash of the object.""" return hash(id(self))
class MinibatchIndexRV(IntegersRV): _print_name = ("minibatch_index", r"\operatorname{minibatch\_index}") minibatch_index = MinibatchIndexRV() class MinibatchOp(OpFromGraph): """Encapsulate Minibatch random draws in an opaque OFG.""" def __init__(self, *args, **kwargs): super().__init__(*args, **kwargs, inline=True) def __str__(self): return "Minibatch" def is_valid_observed(v) -> bool: if not isinstance(v, Variable): # Non-symbolic constant return True if v.owner is None: # Symbolic root variable (constant or not) return True return ( # The only PyTensor operation we allow on observed data is type casting # Although we could allow for any graph that does not depend on other RVs ( isinstance(v.owner.op, Elemwise) and isinstance(v.owner.op.scalar_op, Cast) and is_valid_observed(v.owner.inputs[0]) ) # Or Minibatch or ( isinstance(v.owner.op, MinibatchOp) and all(is_valid_observed(inp) for inp in v.owner.inputs) ) # Or Generator or isinstance(v.owner.op, GeneratorOp) )
[docs] def Minibatch(variable: TensorVariable, *variables: TensorVariable, batch_size: int): """Get random slices from variables from the leading dimension. Parameters ---------- variable: TensorVariable variables: TensorVariable batch_size: int Examples -------- >>> data1 = np.random.randn(100, 10) >>> data2 = np.random.randn(100, 20) >>> mdata1, mdata2 = Minibatch(data1, data2, batch_size=10) """ if not isinstance(batch_size, int): raise TypeError("batch_size must be an integer") tensors = tuple(map(pt.as_tensor, (variable, *variables))) for i, v in enumerate(tensors): if not is_valid_observed(v): raise ValueError( f"{i}: {v} is not valid for Minibatch, only constants or constants.astype(dtype) are allowed" ) upper = tensors[0].shape[0] if len(tensors) > 1: upper = Assert( "All variables shape[0] in Minibatch should be equal, check your Minibatch(data1, data2, ...) code" )(upper, pt.all([pt.eq(upper, other_tensor.shape[0]) for other_tensor in tensors[1:]])) rng = pytensor.shared(np.random.default_rng()) rng_update, mb_indices = minibatch_index(0, upper, size=batch_size, rng=rng).owner.outputs mb_tensors = [tensor[mb_indices] for tensor in tensors] # Wrap graph in OFG so it's easily identifiable and not rewritten accidentally *mb_tensors, _ = MinibatchOp([*tensors, rng], [*mb_tensors, rng_update])(*tensors, rng) for i, r in enumerate(mb_tensors[:-1]): r.name = f"minibatch.{i}" return mb_tensors if len(variables) else mb_tensors[0]
def determine_coords( model, value: pd.DataFrame | pd.Series | xr.DataArray, dims: Sequence[str] | None = None, coords: dict[str, Sequence | np.ndarray] | None = None, ) -> tuple[dict[str, Sequence | np.ndarray], Sequence[str] | Sequence[None]]: """Determine coordinate values from data or the model (via ``dims``).""" if coords is None: coords = {} dim_name = None # If value is a df or a series, we interpret the index as coords: if hasattr(value, "index"): if dims is not None: dim_name = dims[0] if dim_name is None and value.index.name is not None: dim_name = value.index.name if dim_name is not None: coords[dim_name] = value.index # If value is a df, we also interpret the columns as coords: if hasattr(value, "columns"): if dims is not None: dim_name = dims[1] if dim_name is None and value.columns.name is not None: dim_name = value.columns.name if dim_name is not None: coords[dim_name] = value.columns if isinstance(value, xr.DataArray): if dims is not None: for dim in dims: dim_name = dim # str is applied because dim entries may be None coords[str(dim_name)] = cast(xr.DataArray, value[dim]).to_numpy() if isinstance(value, np.ndarray) and dims is not None: if len(dims) != value.ndim: raise pm.exceptions.ShapeError( "Invalid data shape. The rank of the dataset must match the " "length of `dims`.", actual=value.shape, expected=value.ndim, ) for size, dim in zip(value.shape, dims): coord = model.coords.get(dim, None) if coord is None and dim is not None: coords[dim] = range(size) if dims is None: # TODO: Also determine dim names from the index new_dims: Sequence[str] | Sequence[None] = [None] * np.ndim(value) else: new_dims = dims return coords, new_dims
[docs] def ConstantData( name: str, value, *, dims: Sequence[str] | None = None, coords: dict[str, Sequence | np.ndarray] | None = None, infer_dims_and_coords=False, **kwargs, ) -> TensorConstant: """Alias for ``pm.Data``. Registers the ``value`` as a :class:`~pytensor.tensor.TensorConstant` with the model. For more information, please reference :class:`pymc.Data`. """ warnings.warn( "ConstantData is deprecated. All Data variables are now mutable. Use Data instead.", FutureWarning, ) var = Data( name, value, dims=dims, coords=coords, infer_dims_and_coords=infer_dims_and_coords, **kwargs, ) return cast(TensorConstant, var)
[docs] def MutableData( name: str, value, *, dims: Sequence[str] | None = None, coords: dict[str, Sequence | np.ndarray] | None = None, infer_dims_and_coords=False, **kwargs, ) -> SharedVariable: """Alias for ``pm.Data``. Registers the ``value`` as a :class:`~pytensor.compile.sharedvalue.SharedVariable` with the model. For more information, please reference :class:`pymc.Data`. """ warnings.warn( "MutableData is deprecated. All Data variables are now mutable. Use Data instead.", FutureWarning, ) var = Data( name, value, dims=dims, coords=coords, infer_dims_and_coords=infer_dims_and_coords, **kwargs, ) return cast(SharedVariable, var)
[docs] def Data( name: str, value, *, dims: Sequence[str] | None = None, coords: dict[str, Sequence | np.ndarray] | None = None, infer_dims_and_coords=False, mutable: bool | None = None, **kwargs, ) -> SharedVariable | TensorConstant: """Create a data container that registers a data variable with the model. Depending on the ``mutable`` setting (default: True), the variable is registered as a :class:`~pytensor.compile.sharedvalue.SharedVariable`, enabling it to be altered in value and shape, but NOT in dimensionality using :func:`pymc.set_data`. To set the value of the data container variable, check out :meth:`pymc.Model.set_data`. When making predictions or doing posterior predictive sampling, the shape of the registered data variable will most likely need to be changed. If you encounter an PyTensor shape mismatch error, refer to the documentation for :meth:`pymc.model.set_data`. For more information, read the notebook :ref:`nb:data_container`. Parameters ---------- name : str The name for this variable. value : array_like or pandas.Series, pandas.Dataframe A value to associate with this variable. dims : str, tuple of str or tuple of None, optional Dimension names of the random variables (as opposed to the shapes of these random variables). Use this when ``value`` is a pandas Series or DataFrame. The ``dims`` will then be the name of the Series / DataFrame's columns. See ArviZ documentation for more information about dimensions and coordinates: :ref:`arviz:quickstart`. If this parameter is not specified, the random variables will not have dimension names. coords : dict, optional Coordinate values to set for new dimensions introduced by this ``Data`` variable. export_index_as_coords : bool Deprecated, previous version of "infer_dims_and_coords" infer_dims_and_coords : bool, default=False If True, the ``Data`` container will try to infer what the coordinates and dimension names should be if there is an index in ``value``. **kwargs : dict, optional Extra arguments passed to :func:`pytensor.shared`. Examples -------- >>> import pymc as pm >>> import numpy as np >>> # We generate 10 datasets >>> true_mu = [np.random.randn() for _ in range(10)] >>> observed_data = [mu + np.random.randn(20) for mu in true_mu] >>> with pm.Model() as model: ... data = pm.Data("data", observed_data[0]) ... mu = pm.Normal("mu", 0, 10) ... pm.Normal("y", mu=mu, sigma=1, observed=data) >>> # Generate one trace for each dataset >>> idatas = [] >>> for data_vals in observed_data: ... with model: ... # Switch out the observed dataset ... model.set_data("data", data_vals) ... idatas.append(pm.sample()) """ if coords is None: coords = {} if isinstance(value, list): value = np.array(value) # Add data container to the named variables of the model. model = pm.Model.get_context(error_if_none=False) if model is None: raise TypeError( "No model on context stack, which is needed to instantiate a data container. " "Add variable inside a 'with model:' block." ) name = model.name_for(name) # Transform `value` it to something digestible for PyTensor. if isgenerator(value): raise NotImplementedError( "Generator type data is no longer supported with pm.Data.", # It messes up InferenceData and can't be the input to a SharedVariable. ) else: arr = convert_data(value) if isinstance(arr, np.ma.MaskedArray): raise NotImplementedError( "Masked arrays or arrays with `nan` entries are not supported. " "Pass them directly to `observed` if you want to trigger auto-imputation" ) if mutable is not None: warnings.warn( "Data is now always mutable. Specifying the `mutable` kwarg will raise an error in a future release", FutureWarning, ) x = pytensor.shared(arr, name, **kwargs) if isinstance(dims, str): dims = (dims,) if not (dims is None or len(dims) == x.ndim): raise pm.exceptions.ShapeError( "Length of `dims` must match the dimensions of the dataset.", actual=len(dims), expected=x.ndim, ) new_dims: Sequence[str] | Sequence[None] | None if infer_dims_and_coords: coords, new_dims = determine_coords(model, value, dims) else: new_dims = dims if new_dims: xshape = x.shape # Register new dimension lengths for d, dname in enumerate(new_dims): if dname not in model.dim_lengths and dname is not None: model.add_coord( name=dname, # Note: Coordinate values can't be taken from # the value, because it could be N-dimensional. values=coords.get(dname, None), length=xshape[d], ) model.register_data_var(x, dims=new_dims) return x