Source code for podpac.core.compositor

Compositor Summary

from __future__ import division, unicode_literals, print_function, absolute_import

from multiprocessing.pool import ThreadPool
import numpy as np
import traitlets as tl

# Internal imports
from podpac.core.settings import settings
from podpac.core.coordinates import Coordinates, merge_dims
from podpac.core.node import Node
from podpac.core.utils import common_doc
from podpac.core.utils import ArrayTrait
from podpac.core.node import COMMON_NODE_DOC 
from podpac.core.node import node_eval 
from import COMMON_DATA_DOC
from import interpolation_trait
from podpac.core.utils import trait_is_defined


[docs]@common_doc(COMMON_COMPOSITOR_DOC) class Compositor(Node): """Compositor Attributes ---------- cache_native_coordinates : Bool Default is True. If native_coordinates are requested by the user, it may take a long time to calculate if the Compositor points to many sources. The result is relatively small and is cached by default. Caching may not be desired if the datasource change or is updated. interpolation : str, dict, optional {interpolation} is_source_coordinates_complete : Bool Default is False. The source_coordinates do not have to completely describe the source. For example, the source coordinates could include the year-month-day of the source, but the actual source also has hour-minute-second information. In that case, source_coordinates is incomplete. This flag is used to automatically construct native_coordinates. shared_coordinates : :class:`podpac.Coordinates`, optional Coordinates that are shared amongst all of the composited sources source : str The source is used for a unique name to cache composited products. source_coordinates : :class:`podpac.Coordinates` Description sources : :class:`np.ndarray` An array of sources. This is a numpy array as opposed to a list so that boolean indexing may be used to subselect the nodes that will be evaluated. source_coordinates : :class:`podpac.Coordinates`, optional Coordinates that make each source unique. This is used for subsetting which sources to evaluate based on the user-requested coordinates. It is an optimization. Notes ----- Developers of new Compositor nodes need to implement the `composite` method. Multitheading:: * When MULTITHREADING is False, the compositor stops evaluated sources once the output is completely filled. * When MULTITHREADING is True, the compositor must evaluate every source. The result is the same, but note that because of this, disabling multithreading could sometimes be faster, especially if the number of threads is low. * NASA data servers seem to have a hard limit of 10 simultaneous requests, so a max of 10 threads is recommend for most use-cases. """ shared_coordinates = tl.Instance(Coordinates, allow_none=True) source_coordinates = tl.Instance(Coordinates, allow_none=True) is_source_coordinates_complete = tl.Bool(False, help=("This allows some optimizations but assumes that a node's " "native_coordinates=source_coordinate + shared_coordinate " "IN THAT ORDER")) source = tl.Unicode().tag(attr=True) sources = ArrayTrait(ndim=1) cache_native_coordinates = tl.Bool(True) interpolation = interpolation_trait(default_value=None) @tl.default('source') def _source_default(self): source = [] for s in self.sources[:3]: source.append(str(s)) return '_'.join(source) @tl.default('source_coordinates') def _source_coordinates_default(self): return self.get_source_coordinates() # default representation def __repr__(self): source_name = str(self.__class__.__name__) rep = '{}'.format(source_name) rep += '\n\tsource: {}'.format(self.source) rep += '\n\tinterpolation: {}'.format(self.interpolation) return rep
[docs] def get_source_coordinates(self): """ Returns the coordinates describing each source. This may be implemented by derived classes, and is an optimization that allows evaluation subsets of source. Returns ------- :class:`podpac.Coordinates` Coordinates describing each source. """ return None
@tl.default('shared_coordinates') def _shared_coordinates_default(self): return self.get_shared_coordinates()
[docs] def get_shared_coordinates(self): """Coordinates shared by each source. Raises ------ NotImplementedError Description """ raise NotImplementedError()
[docs] def select_sources(self, coordinates): """Downselect compositor sources based on requested coordinates. This is used during the :meth:`eval` process as an optimization when :attr:`source_coordinates` are not pre-defined. Parameters ---------- coordinates : :class:`podpac.Coordinates` Coordinates to evaluate at compositor sources Returns ------- :class:`np.ndarray` Array of downselected sources """ # if source coordinates are defined, use intersect if self.source_coordinates is not None: # intersecting sources only try: _, I = self.source_coordinates.intersect(coordinates, outer=True, return_indices=True) except: # Likely non-monotonic coordinates _, I = self.source_coordinates.intersect(coordinates, outer=False, return_indices=True) src_subset = self.sources[I] # no downselection possible - get all sources compositor else: src_subset = self.sources return src_subset
[docs] def composite(self, outputs, result=None): """Implements the rules for compositing multiple sources together. Parameters ---------- outputs : list A list of outputs that need to be composited together result : UnitDataArray, optional An optional pre-filled array may be supplied, otherwise the output will be allocated. Raises ------ NotImplementedError """ raise NotImplementedError()
[docs] def iteroutputs(self, coordinates): """Summary Parameters ---------- coordinates : :class:`podpac.Coordinates` Coordinates to evaluate at compositor sources Yields ------ :class:`podpac.core.units.UnitsDataArray` Output from source node eval method """ # downselect sources based on coordinates src_subset = self.select_sources(coordinates) if len(src_subset) == 0: yield self.create_output_array(coordinates) return # Set the interpolation properties for sources if self.interpolation is not None: for s in src_subset.ravel(): if trait_is_defined(self, 'interpolation'): s.interpolation = self.interpolation # Optimization: if coordinates complete and source coords is 1D, # set native_coordinates unless they are set already # WARNING: this assumes # native_coords = source_coords + shared_coordinates # NOT native_coords = shared_coords + source_coords if self.is_source_coordinates_complete and self.source_coordinates.ndim == 1: coords_subset = list(self.source_coordinates.intersect(coordinates, outer=True).coords.values())[0] coords_dim = list(self.source_coordinates.dims)[0] for s, c in zip(src_subset, coords_subset): nc = merge_dims([Coordinates(np.atleast_1d(c), dims=[coords_dim]), self.shared_coordinates]) if trait_is_defined(s,'native_coordinates') is False: s.native_coordinates = nc if settings['MULTITHREADING']: # TODO pool of pre-allocated scratch space # TODO: docstring? def f(src): return src.eval(coordinates) pool = ThreadPool(processes=settings.get('N_THREADS', 10)) results = [pool.apply_async(f, [src]) for src in src_subset] for src, res in zip(src_subset, results): yield res.get() #src._output = None # free up memory else: output = None # scratch space for src in src_subset: output = src.eval(coordinates, output) yield output
#output[:] = np.nan
[docs] @node_eval @common_doc(COMMON_COMPOSITOR_DOC) def eval(self, coordinates, output=None): """Evaluates this nodes using the supplied coordinates. Parameters ---------- coordinates : :class:`podpac.Coordinates` {requested_coordinates} output : podpac.UnitsDataArray, optional {eval_output} Returns ------- {eval_return} """ self._requested_coordinates = coordinates outputs = self.iteroutputs(coordinates) output = self.composite(outputs, output) return output
[docs] def find_coordinates(self): """ Get the available native coordinates for the Node. Returns ------- coords_list : list list of available coordinates (Coordinate objects) """ raise NotImplementedError("TODO")
@property @common_doc(COMMON_COMPOSITOR_DOC) def base_definition(self): """Base node defintion for Compositor nodes. Returns ------- {definition_return} """ d = super(Compositor, self).base_definition d['sources'] = self.sources d['interpolation'] = self.interpolation return d
[docs]class OrderedCompositor(Compositor): """Compositor that combines sources based on their order in self.sources. Once a request contains no nans, the result is returned. """
[docs] @common_doc(COMMON_COMPOSITOR_DOC) def composite(self, outputs, result=None): """Composites outputs in order that they appear. Parameters ---------- outputs : generator Generator that gives UnitDataArray's with the source values. result : None, optional Description Returns ------- {eval_return} This composites the sources together until there are no nans or no more sources. """ if result is None: # consume the first source output result = next(outputs).copy() # initialize the mask # if result is None, probably this is all false mask = np.isfinite( if np.all(mask): return result # loop through remaining outputs for output in outputs: output = output.transpose(*result.dims) source_mask = np.isfinite( b = ~mask & source_mask[b] =[b] mask |= source_mask # stop if the results are full if np.all(mask): break return result