Source code for openquake.hazardlib.calc.filters

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
#
# Copyright (C) 2012-2018 GEM Foundation
#
# OpenQuake is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# OpenQuake is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
# along with OpenQuake. If not, see <http://www.gnu.org/licenses/>.

import sys
import operator
import collections
from contextlib import contextmanager
import numpy
try:
    import rtree
except ImportError:
    rtree = None
from scipy.interpolate import interp1d
from openquake.baselib import hdf5, config
from openquake.baselib.parallel import Starmap
from openquake.baselib.general import gettemp, groupby
from openquake.baselib.python3compat import raise_
from openquake.hazardlib.geo.utils import (
    KM_TO_DEGREES, angular_distance, within, fix_lon, get_bounding_box)

MAX_DISTANCE = 2000  # km, ultra big distance used if there is no filter
src_group_id = operator.attrgetter('src_group_id')


[docs]@contextmanager def context(src): """ Used to add the source_id to the error message. To be used as with context(src): operation_with(src) Typically the operation is filtering a source, that can fail for tricky geometries. """ try: yield except Exception: etype, err, tb = sys.exc_info() msg = 'An error occurred with source id=%s. Error: %s' msg %= (src.source_id, err) raise_(etype, msg, tb)
[docs]def getdefault(dic_with_default, key): """ :param dic_with_default: a dictionary with a 'default' key :param key: a key that may be present in the dictionary or not :returns: the value associated to the key, or to 'default' """ try: return dic_with_default[key] except KeyError: return dic_with_default['default']
[docs]class Piecewise(object): """ Given two arrays x and y of non-decreasing values, build a piecewise function associating to each x the corresponding y. If x is smaller then the minimum x, the minimum y is returned; if x is larger than the maximum x, the maximum y is returned. """ def __init__(self, x, y): self.y = numpy.array(y) # interpolating from x values to indices in the range [0: len(x)] self.piecewise = interp1d(x, range(len(x)), bounds_error=False, fill_value=(0, len(x) - 1)) def __call__(self, x): idx = numpy.int64(numpy.ceil(self.piecewise(x))) return self.y[idx]
[docs]class IntegrationDistance(collections.Mapping): """ Pickleable object wrapping a dictionary of integration distances per tectonic region type. The integration distances can be scalars or list of pairs (magnitude, distance). Here is an example using 'default' as tectonic region type, so that the same values will be used for all tectonic region types: >>> maxdist = IntegrationDistance({'default': [ ... (3, 30), (4, 40), (5, 100), (6, 200), (7, 300), (8, 400)]}) >>> maxdist('Some TRT', mag=2.5) 30 >>> maxdist('Some TRT', mag=3) 30 >>> maxdist('Some TRT', mag=3.1) 40 >>> maxdist('Some TRT', mag=8) 400 >>> maxdist('Some TRT', mag=8.5) # 2000 km are used above the maximum 2000 It has also a method `.get_closest(sites, rupture)` returning the closest sites to the rupture and their distances. The integration distance can be missing if the sites have been already filtered (empty dictionary): in that case the method returns all the sites and all the distances. """ def __init__(self, dic): self.dic = dic or {} # TRT -> float or list of pairs self.magdist = {} # TRT -> (magnitudes, distances) for trt, value in self.dic.items(): if isinstance(value, list): # assume a list of pairs (mag, dist) self.magdist[trt] = value else: self.dic[trt] = float(value) def __call__(self, trt, mag=None): value = getdefault(self.dic, trt) if isinstance(value, float): # scalar maximum distance return value elif mag is None: # get the maximum distance return MAX_DISTANCE elif not hasattr(self, 'piecewise'): self.piecewise = {} # function cache try: md = self.piecewise[trt] # retrieve from the cache except KeyError: # fill the cache mags, dists = zip(*getdefault(self.magdist, trt)) if mags[-1] < 11: # use 2000 km for mag > mags[-1] mags = numpy.concatenate([mags, [11]]) dists = numpy.concatenate([dists, [MAX_DISTANCE]]) md = self.piecewise[trt] = Piecewise(mags, dists) return md(mag)
[docs] def get_bounding_box(self, lon, lat, trt=None, mag=None): """ Build a bounding box around the given lon, lat by computing the maximum_distance at the given tectonic region type and magnitude. :param lon: longitude :param lat: latitude :param trt: tectonic region type, possibly None :param mag: magnitude, possibly None :returns: min_lon, min_lat, max_lon, max_lat """ if trt is None: # take the greatest integration distance maxdist = max(self(trt, mag) for trt in self.dic) else: # get the integration distance for the given TRT maxdist = self(trt, mag) a1 = min(maxdist * KM_TO_DEGREES, 90) a2 = min(angular_distance(maxdist, lat), 180) return lon - a2, lat - a1, lon + a2, lat + a1
[docs] def get_affected_box(self, src): """ Get the enlarged bounding box of a source. :param src: a source object :returns: a bounding box (min_lon, min_lat, max_lon, max_lat) """ mag = src.get_min_max_mag()[1] maxdist = self(src.tectonic_region_type, mag) bbox = get_bounding_box(src, maxdist) return (fix_lon(bbox[0]), bbox[1], fix_lon(bbox[2]), bbox[3])
def __getstate__(self): # otherwise is not pickleable due to .piecewise return dict(dic=self.dic, magdist=self.magdist) def __getitem__(self, trt): return self(trt) def __iter__(self): return iter(self.dic) def __len__(self): return len(self.dic) def __repr__(self): return repr(self.dic)
[docs]def prefilter(srcs, srcfilter, monitor): """ :returns: a dict src_group_id -> sources """ return groupby(srcfilter.filter(srcs), src_group_id)
[docs]class SourceFilter(object): """ Filter objects have a .filter method yielding filtered sources, i.e. sources with an attribute .indices, containg the IDs of the sites within the given maximum distance. There is also a .pfilter method that filters the sources in parallel and returns a dictionary src_group_id -> filtered sources. Filter the sources by using `self.sitecol.within_bbox` which is based on numpy. """ def __init__(self, sitecol, integration_distance, hdf5path=None): if sitecol is not None and len(sitecol) < len(sitecol.complete): raise ValueError('%s is not complete!' % sitecol) self.hdf5path = hdf5path if hdf5path and ( config.distribution.oq_distribute in ('no', 'processpool') or config.directory.shared_dir): # store the sitecol with hdf5.File(hdf5path, 'w') as h5: h5['sitecol'] = sitecol else: # keep the sitecol in memory self.__dict__['sitecol'] = sitecol self.integration_distance = ( IntegrationDistance(integration_distance) if isinstance(integration_distance, dict) else integration_distance) self.distribute = None @property def sitecol(self): """ Read the site collection from .hdf5path and cache it """ if 'sitecol' in vars(self): return self.__dict__['sitecol'] with hdf5.File(self.hdf5path, 'r') as h5: self.__dict__['sitecol'] = sc = h5['sitecol'] return sc
[docs] def get_rectangle(self, src): """ :param src: a source object :returns: ((min_lon, min_lat), width, height), useful for plotting """ min_lon, min_lat, max_lon, max_lat = ( self.integration_distance.get_affected_box(src)) return (min_lon, min_lat), (max_lon - min_lon) % 360, max_lat - min_lat
[docs] def get_close_sites(self, source): """ Returns the sites within the integration distance from the source, or None. """ source_sites = list(self([source])) if source_sites: return source_sites[0][1]
def __call__(self, sources): """ :yields: pairs (src, sites) """ if not self.integration_distance: # do not filter for src in sources: yield src, self.sitecol return for src in self.filter(sources): yield src, self.sitecol.filtered(src.indices) # used in the disaggregation calculator
[docs] def get_bounding_boxes(self, trt=None, mag=None): """ :param trt: a tectonic region type (used for the integration distance) :param mag: a magnitude (used for the integration distance) :returns: a list of bounding boxes, one per site """ bbs = [] for site in self.sitecol: bb = self.integration_distance.get_bounding_box( site.location.longitude, site.location.latitude, trt, mag) bbs.append(bb) return bbs
[docs] def filter(self, sources): """ :param sources: a sequence of sources :yields: sources with .indices """ for src in sources: if hasattr(src, 'indices'): # already filtered yield src continue box = self.integration_distance.get_affected_box(src) indices = self.sitecol.within_bbox(box) if len(indices): src.indices = indices yield src
[docs] def pfilter(self, sources, monitor): """ Filter the sources in parallel by using Starmap.apply :param sources: a sequence of sources :param monitor: a Monitor instance :returns: a dictionary src_group_id -> sources """ sources_by_grp = Starmap.apply( prefilter, (sources, self, monitor), distribute=self.distribute, name=self.__class__.__name__).reduce() Starmap.shutdown() # close the processpool Starmap.init() # reopen it when necessary # avoid task ordering issues for sources in sources_by_grp.values(): sources.sort(key=operator.attrgetter('source_id')) return sources_by_grp
[docs]class RtreeFilter(SourceFilter): """ The RtreeFilter uses the rtree library. The index is generated at instantiation time and stored in a temporary file. The filter should be instantiated only once per calculation, after the site collection is known. It should be used as follows:: rfilter = RtreeFilter(sitecol, integration_distance) for src, sites in rfilter(sources): do_something(...) As a side effect, sets the `.indices` attribute of the source, i.e. the number of sites within the integration distance. Notice that libspatialindex indices cannot be properly pickled (https://github.com/Toblerity/rtree/issues/65) this is why they must be saved on the file system where they can be read from the workers. NB: an RtreeFilter has an .indexpath attribute, but not a .sitecol attribute nor an .index attribute, so it can be pickled and transferred easily. :param sitecol: :class:`openquake.hazardlib.site.SiteCollection` instance :param integration_distance: Integration distance dictionary (TRT -> distance in km) """ def __init__(self, sitecol, integration_distance, hdf5path=None): if rtree is None: raise ImportError('rtree') super().__init__(sitecol, integration_distance, hdf5path) self.distribute = 'processpool' self.indexpath = gettemp() lonlats = zip(sitecol.lons, sitecol.lats) index = rtree.index.Index(self.indexpath) for i, (lon, lat) in enumerate(lonlats): index.insert(i, (lon, lat, lon, lat)) index.close()
[docs] def filter(self, sources): """ :param sources: a sequence of sources :yields: rtree-filtered sources """ index = rtree.index.Index(self.indexpath) try: for src in sources: box = self.integration_distance.get_affected_box(src) indices = within(box, index) if len(indices): src.indices = indices yield src finally: index.close()
source_site_noop_filter = SourceFilter(None, {})