import logging
from functools import partial
from importlib import import_module
from inspect import signature
from itertools import chain, repeat
from pathlib import Path
from types import ModuleType
from typing import (
Any,
Callable,
Dict,
Iterable,
List,
Mapping,
Optional,
Sequence,
Tuple,
Union,
cast,
)
from warnings import warn
import dask
import pint
from dask import get as dask_get # NB dask.threaded.get causes JPype to segfault
from dask.optimization import cull
from genno import computations
from genno.caching import make_cache_decorator
from genno.util import partial_split
from .describe import describe_recursive
from .exceptions import ComputationError, KeyExistsError, MissingKeyError
from .key import Key, KeyLike
log = logging.getLogger(__name__)
[docs]class Computer:
"""Class for describing and executing computations.
Parameters
----------
kwargs :
Passed to :meth:`configure`.
"""
#: A dask-format graph (see :doc:`1 <dask:graphs>`, :doc:`2 <dask:spec>`).
graph: Dict[str, Any] = {"config": {}}
#: The default key to :meth:`.get` with no argument.
default_key = None
# An index of key names -> full keys.
_index: Dict[str, Key] = {}
#: List of modules containing pre-defined computations.
#:
#: By default, this includes the :mod:`genno` built-in computations in
#: :mod:`genno.computations`. :meth:`require_compat` appends additional modules,
#: e.g. #: :mod:`.compat.pyam.computations`, to this list. User code may also add
#: modules to this list.
modules: Sequence[ModuleType] = [computations]
def __init__(self, **kwargs):
self.graph = {"config": {}}
self._index = {}
self.configure(**kwargs)
[docs] def get_comp(self, name) -> Optional[Callable]:
"""Return a computation function.
:meth:`get_comp` checks each of the :attr:`modules` for a function or callable
with the given `name`. Modules at the end of the list take precedence over those
earlier in the lists.
Returns
-------
.callable
None
If there is no computation with the given `name` in any of :attr:`modules`.
"""
for module in reversed(self.modules):
try:
return getattr(module, name)
except AttributeError:
continue # `name` not in this module
except TypeError:
return None # `name` is not a string; can't be the name of a function
return None
[docs] def require_compat(self, pkg: str):
"""Load computations from ``genno.compat.{pkg}`` for use with :func:`.get_comp`.
The specified module is appended to :attr:`modules`.
Raises
------
ModuleNotFoundError
If the required packages are missing.
See also
--------
.get_comp
"""
name = f"genno.compat.{pkg}"
if not getattr(import_module(name), f"HAS_{pkg.upper()}"):
raise ModuleNotFoundError(
f"No module named '{pkg}', required by genno.compat.{pkg}"
)
self.modules = list(self.modules) + [import_module(f"{name}.computations")]
[docs] def add(self, data, *args, **kwargs):
"""General-purpose method to add computations.
:meth:`add` can be called in several ways; its behaviour depends on `data`; see
below. It chains to methods such as :meth:`add_single`, :meth:`add_queue`,
and/or :meth:`apply`; each can also be called directly.
Returns
-------
list of Key-like
Some or all of the keys added to the Computer.
See also
---------
add_single
add_queue
apply
"""
if isinstance(data, list):
# A list. Use add_queue to add
return self.add_queue(data, *args, **kwargs)
elif isinstance(data, str) and self.get_comp(data):
# *data* is the name of a pre-defined computation
name = data
if hasattr(self, f"add_{name}"):
# Use a method on the current class to add. This invokes any
# argument-handling conveniences, e.g. Computer.add_product()
# instead of using the bare product() computation directly.
return getattr(self, f"add_{name}")(*args, **kwargs)
else:
# Get the function directly
func = self.get_comp(name)
# Rearrange arguments: key, computation function, args, …
func, kwargs = partial_split(func, kwargs)
return self.add(args[0], func, *args[1:], **kwargs)
elif isinstance(data, str) and data in dir(self):
# Name of another method, e.g. 'apply'
return getattr(self, data)(*args, **kwargs)
elif isinstance(data, (str, Key)):
# *data* is a key, *args* are the computation
key, computation = data, args
if kwargs.pop("sums", False):
# Convert *key* to a Key object in order to use .iter_sums()
key = Key.from_str_or_key(key)
# Iterable of computations
# print((tuple([key] + list(computation)), kwargs))
# print([(c, {}) for c in key.iter_sums()])
to_add = chain(
# The original
[(tuple([key] + list(computation)), kwargs)],
# One entry for each sum
[(c, {}) for c in key.iter_sums()],
)
return self.add_queue(to_add)
else:
# Add a single computation (without converting to Key)
return self.add_single(key, *computation, **kwargs)
else:
# Some other kind of input
raise TypeError(data)
[docs] def cache(self, func):
"""Return a decorator to cache data."""
return make_cache_decorator(self, func)
[docs] def add_queue(
self,
queue: Iterable[Tuple[Tuple, Mapping]],
max_tries: int = 1,
fail: Union[str, int] = "raise",
) -> Tuple[KeyLike, ...]:
"""Add tasks from a list or `queue`.
Parameters
----------
queue : iterable of 2-:class:`tuple`
The members of each tuple are the arguments (e.g. :class:`list` or tuple)
and keyword arguments (e.g :class:`dict`) to :meth:`add`.
max_tries : int, optional
Retry adding elements up to this many times.
fail : "raise" or str or :mod:`logging` level, optional
Action to take when a computation from `queue` cannot be added after
`max_tries`: "raise" an exception, or log messages on the indicated level
and continue.
"""
# Elements to retry: list of (tries, args, kwargs)
retry: List[Tuple[int, Tuple[Tuple, Mapping]]] = []
added: List[KeyLike] = []
# Iterate over elements from queue, then from retry. On the first pass,
# count == 1; on subsequent passes, it is incremented.
for count, (args, kwargs) in chain(zip(repeat(1), queue), retry):
try:
# Recurse
key_or_keys = self.add(*args, **kwargs)
except KeyError as exc:
# Adding failed
# Information for debugging
info = [
f"Failed {count} times to add:",
f" ({repr(args)}, {repr(kwargs)})",
f" with {repr(exc)}",
]
def _log(level):
[log.log(level, i) for i in info]
if count < max_tries:
_log(logging.DEBUG)
# This may only be due to items being out of order, so
# retry silently
retry.append((count + 1, (args, kwargs)))
else:
# More than *max_tries* failures; something has gone wrong
if fail == "raise":
_log(logging.ERROR)
raise
else:
_log(
getattr(logging, fail.upper())
if isinstance(fail, str)
else fail
)
else:
if isinstance(key_or_keys, tuple):
added.extend(key_or_keys)
else:
added.append(key_or_keys)
return tuple(added)
# Generic graph manipulations
[docs] def add_single(self, key, *computation, strict=False, index=False):
"""Add a single `computation` at `key`.
Parameters
----------
key : str or Key or hashable
A string, Key, or other value identifying the output of `computation`.
computation : object
Any computation. See :attr:`graph`.
strict : bool, optional
If True, `key` must not already exist in the Computer, and any keys
referred to by `computation` must exist.
index : bool, optional
If True, `key` is added to the index as a full-resolution key, so it can be
later retrieved with :meth:`full_key`.
Raises
------
KeyExistsError
If `strict` is :obj:`True` and either (a) `key` already exists; or (b)
`sums` is :obj:`True` and the key for one of the partial sums of `key`
already exists.
MissingKeyError
If `strict` is :obj:`True` and any key referred to by `computation` does
not exist.
"""
if len(computation) == 1:
# Unpack a length-1 tuple
computation = computation[0]
if strict:
if key in self.graph:
# Key already exists in graph
raise KeyExistsError(key)
# Check valid computations: a tuple with a callable, or a list of other
# keys. Don't check a single value that is iterable, e.g. pd.DataFrame
if isinstance(computation, (list, tuple)):
# Check that keys used in *comp* are in the graph
keylike = filter(lambda e: isinstance(e, (str, Key)), computation)
self.check_keys(*keylike)
if index:
# String equivalent of *key* with all dimensions dropped, but name
# and tag retained
idx = str(Key.from_str_or_key(key, drop=True)).rstrip(":")
# Add *key* to the index
self._index[idx] = key
# Add to the graph
self.graph[key] = computation
return key
[docs] def apply(self, generator, *keys, **kwargs):
"""Add computations by applying `generator` to `keys`.
Parameters
----------
generator : callable
Function to apply to `keys`.
keys : hashable
The starting key(s).
kwargs
Keyword arguments to `generator`.
"""
args = self.check_keys(*keys)
try:
# Inspect the generator function
par = signature(generator).parameters
# Name of the first parameter
par_0 = list(par.keys())[0]
except IndexError:
pass # No parameters to generator
else:
if issubclass(par[par_0].annotation, Computer):
# First parameter wants a reference to the Computer object
args.insert(0, self)
# Call the generator. Might return None, or yield some computations
applied = generator(*args, **kwargs)
if applied:
# Update the graph with the computations
self.graph.update(applied)
[docs] def get(self, key=None):
"""Execute and return the result of the computation *key*.
Only *key* and its dependencies are computed.
Parameters
----------
key : str, optional
If not provided, :attr:`default_key` is used.
Raises
------
ValueError
If `key` and :attr:`default_key` are both :obj:`None`.
"""
if key is None:
if self.default_key is not None:
key = self.default_key
else:
raise ValueError("no default reporting key set")
# Protect 'config' dict, so that dask schedulers do not try to interpret its
# contents as further tasks. Workaround for
# https://github.com/dask/dask/issues/3523
self.graph["config"] = dask.core.quote(self.graph.get("config", dict()))
# Cull the graph, leaving only those needed to compute *key*
dsk, deps = cull(self.graph, key)
log.debug(f"Cull {len(self.graph)} -> {len(dsk)} keys")
try:
result = dask_get(dsk, key)
except Exception as exc:
raise ComputationError(exc) from None
else:
return result
finally:
self.graph["config"] = self.graph["config"][0].data
[docs] def keys(self):
"""Return the keys of :attr:`graph`."""
return self.graph.keys()
[docs] def full_key(self, name_or_key):
"""Return the full-dimensionality key for *name_or_key*.
An quantity 'foo' with dimensions (a, c, n, q, x) is available in the Computer
as ``'foo:a-c-n-q-x'``. This :class:`.Key` can be retrieved with::
c.full_key("foo")
c.full_key("foo:c")
# etc.
"""
name = str(Key.from_str_or_key(name_or_key, drop=True)).rstrip(":")
return self._index[name]
[docs] def check_keys(self, *keys):
"""Check that *keys* are in the Computer.
If any of *keys* is not in the Computer, KeyError is raised.
Otherwise, a list is returned with either the key from *keys*, or the
corresponding :meth:`full_key`.
"""
result = []
missing = []
# Process all keys to produce more useful error messages
for key in keys:
# Add the key directly if it is in the graph
if key in self.graph:
result.append(key)
continue
# Try adding the full key
try:
result.append(self._index[key])
except KeyError:
missing.append(key)
if len(missing):
raise MissingKeyError(*missing)
return result
[docs] def infer_keys(self, key_or_keys, dims=[]):
"""Infer complete `key_or_keys`.
Parameters
----------
dims : list of str, optional
Drop all but these dimensions from the returned key(s).
"""
single = isinstance(key_or_keys, (str, Key))
result = []
for k in [key_or_keys] if single else key_or_keys:
# Has some dimensions or tag
key = Key.from_str_or_key(k) if ":" in k else k
if "::" in k or key not in self:
key = self.full_key(key)
if dims:
# Drop all but *dims*
key = key.drop(*[d for d in key.dims if d not in dims])
result.append(key)
return result[0] if single else tuple(result)
def __contains__(self, name):
return name in self.graph
# Convenience methods
[docs] def add_product(self, key, *quantities, sums=True):
"""Add a computation that takes the product of *quantities*.
Parameters
----------
key : str or Key
Key of the new quantity. If a Key, any dimensions are ignored; the
dimensions of the product are the union of the dimensions of
*quantities*.
sums : bool, optional
If :obj:`True`, all partial sums of the new quantity are also
added.
Returns
-------
:class:`Key`
The full key of the new quantity.
"""
# Fetch the full key for each quantity
base_keys = list(map(Key.from_str_or_key, self.check_keys(*quantities)))
# Compute a key for the result
# Parse the name and tag of the target
key = Key.from_str_or_key(key)
# New key with dimensions of the product
key = Key.product(key.name, *base_keys, tag=key.tag)
# Add the basic product to the graph and index
keys = self.add(key, computations.product, *base_keys, sums=sums, index=True)
return keys[0]
[docs] def aggregate(self, qty, tag, dims_or_groups, weights=None, keep=True, sums=False):
"""Add a computation that aggregates *qty*.
Parameters
----------
qty: :class:`Key` or str
Key of the quantity to be aggregated.
tag: str
Additional string to add to the end the key for the aggregated
quantity.
dims_or_groups: str or iterable of str or dict
Name(s) of the dimension(s) to sum over, or nested dict.
weights : :class:`xarray.DataArray`, optional
Weights for weighted aggregation.
keep : bool, optional
Passed to :meth:`computations.aggregate <genno.computations.aggregate>`.
sums : bool, optional
Passed to :meth:`add`.
Returns
-------
:class:`Key`
The key of the newly-added node.
"""
# TODO maybe split this to two methods?
if isinstance(dims_or_groups, dict):
groups = dims_or_groups
if len(groups) > 1:
raise NotImplementedError("aggregate() along >1 dimension")
key = Key.from_str_or_key(qty, tag=tag)
comp = (computations.aggregate, qty, groups, keep)
else:
dims = dims_or_groups
if isinstance(dims, str):
dims = [dims]
key = Key.from_str_or_key(qty, drop=dims, tag=tag)
comp = (partial(computations.sum, dimensions=dims), qty, weights)
return self.add(key, comp, strict=True, index=True, sums=sums)
add_aggregate = aggregate
[docs] def disaggregate(self, qty, new_dim, method="shares", args=[]):
"""Add a computation that disaggregates `qty` using `method`.
Parameters
----------
qty: hashable
Key of the quantity to be disaggregated.
new_dim: str
Name of the new dimension of the disaggregated variable.
method: callable or str
Disaggregation method. If a callable, then it is applied to `var` with any
extra `args`. If a string, then a method named 'disaggregate_{method}' is
used.
args: list, optional
Additional arguments to the `method`. The first element should be the key
for a quantity giving shares for disaggregation.
Returns
-------
:class:`Key`
The key of the newly-added node.
"""
# Compute the new key
key = Key.from_str_or_key(qty, append=new_dim)
# Get the method
if isinstance(method, str):
try:
method = getattr(computations, "disaggregate_{}".format(method))
except AttributeError:
raise ValueError(
"No disaggregation method 'disaggregate_{}'".format(method)
)
if not callable(method):
raise TypeError(method)
return self.add(key, tuple([method, qty] + args), strict=True)
[docs] def add_file(self, path, key=None, **kwargs):
"""Add exogenous quantities from *path*.
Computing the `key` or using it in other computations causes `path` to
be loaded and converted to :class:`.Quantity`.
Parameters
----------
path : os.PathLike
Path to the file, e.g. '/path/to/foo.ext'.
key : str or .Key, optional
Key for the quantity read from the file.
Other parameters
----------------
dims : dict or list or set
Either a collection of names for dimensions of the quantity, or a
mapping from names appearing in the input to dimensions.
units : str or pint.Unit
Units to apply to the loaded Quantity.
Returns
-------
.Key
Either `key` (if given) or e.g. ``file:foo.ext`` based on the
`path` name, without directory components.
See also
--------
genno.computations.load_file
"""
path = Path(path)
key = key if key else "file:{}".format(path.name)
return self.add(
key, (partial(self.get_comp("load_file"), path, **kwargs),), strict=True
)
# Use add_file as a helper for computations.load_file
add_load_file = add_file
[docs] def describe(self, key=None, quiet=True):
"""Return a string describing the computations that produce *key*.
If *key* is not provided, all keys in the Computer are described.
The string can be printed to the console, if not *quiet*.
"""
if key is None:
# Sort with 'all' at the end
key = tuple(
sorted(filter(lambda k: k != "all", self.graph.keys())) + ["all"]
)
else:
key = (key,)
result = describe_recursive(self.graph, key)
if not quiet:
print(result, end="\n")
return result
[docs] def visualize(self, filename, **kwargs):
"""Generate an image describing the Computer structure.
This is a shorthand for :meth:`dask.visualize`. Requires
`graphviz <https://pypi.org/project/graphviz/>`__.
"""
return dask.visualize(self.graph, filename=filename, **kwargs)
[docs] def write(self, key, path):
"""Write the result of `key` to the file `path`."""
# Call the method directly without adding it to the graph
key = self.check_keys(key)[0]
self.get_comp("write_report")(self.get(key), path)
@property
def unit_registry(self):
"""The :meth:`pint.UnitRegistry` used by the Computer."""
return pint.get_application_registry()
# For .compat.pyam
# "/, " requires Python 3.8; change only if/when support for Python 3.7 is dropped
# def convert_pyam(self, quantities, tag="iamc", /, **kwargs):
[docs] def convert_pyam(self, quantities, tag="iamc", **kwargs):
"""Add conversion of one or more **quantities** to IAMC format.
Parameters
----------
quantities : str or Key or list of (str, Key)
Keys for quantities to transform.
tag : str, optional
Tag to append to new Keys.
Other parameters
----------------
kwargs :
Any keyword arguments accepted by :func:`.as_pyam`.
Returns
-------
list of Key
Each task converts a :class:`.Quantity` into a :class:`pyam.IamDataFrame`.
See also
--------
.as_pyam
"""
self.require_compat("pyam")
# Handle single vs. iterable of inputs
multi_arg = not isinstance(quantities, (str, Key))
if not multi_arg:
quantities = [quantities]
if len(kwargs.get("replace", {})) and not isinstance(
next(iter(kwargs["replace"].values())), dict
):
kwargs["replace"] = dict(variable=kwargs.pop("replace"))
warn(
f"replace must be nested dict(), e.g. {repr(kwargs['replace'])}",
DeprecationWarning,
)
# Check keys
quantities = self.check_keys(*quantities)
# The callable for the task. If pyam is not available, require_compat() above
# will fail; so this will never be None
comp = partial(cast(Callable, self.get_comp("as_pyam")), **kwargs)
keys = []
for qty in quantities:
# Key for the input quantity
key = Key.from_str_or_key(qty)
# Key for the task
keys.append(":".join([key.name, tag]))
# Add the task and store the key
self.add_single(keys[-1], (comp, "scenario", key))
return tuple(keys) if multi_arg else keys[0]
# Use convert_pyam as a helper for computations.as_pyam
add_as_pyam = convert_pyam