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# https://pyrocko.org - GPLv3 # # The Pyrocko Developers, 21st Century # ---|P------/S----------~Lg----------
from __future__ import absolute_import, print_function, division
import numpy as num
def neighborhood_density(dists, neighborhood=1): sdists = dists.copy() sdists.sort(axis=1) meandists = num.mean(sdists[:, 1:1+neighborhood], axis=1) return meandists
def _weed(dists, badnesses, neighborhood=1, interaction_radius=3., del_frac=4, max_del=100, max_depth=100, depth=0):
if depth > max_depth: assert False, 'max recursion depth reached'
meandists = neighborhood_density(dists, neighborhood)
order = meandists.argsort() candidates = order[:order.size//del_frac+1] badness_candidates = badnesses[candidates] order_badness = (-badness_candidates).argsort()
order[:order.size//del_frac+1] = \ order[:order.size//del_frac+1][order_badness]
deleted = num.zeros(order.size, dtype=num.bool) ndeleted = 0 for i, ind in enumerate(order): if (i < order.size // del_frac // 2 + 1 and ndeleted < max_del and num.all( dists[ind, deleted] > interaction_radius*meandists[ind])):
deleted[ind] = True ndeleted += 1
if ndeleted == 0: return deleted
kept = num.logical_not(deleted).nonzero()[0]
xdists = dists[num.meshgrid(kept, kept)] xbadnesses = badnesses[kept] xdeleted = _weed(xdists, xbadnesses, neighborhood, interaction_radius, del_frac, max_del-ndeleted, max_depth, depth+1)
deleted[kept] = xdeleted return deleted
def weed(x, y, badnesses, neighborhood=1, nwanted=None, interaction_radius=3.): assert x.size == y.size n = x.size NEW = num.newaxis ax = x[NEW, :] ay = y[NEW, :] bx = x[:, NEW] by = y[:, NEW]
if nwanted is None: nwanted = n // 2
dx = num.abs(ax-bx) dx = num.where(dx > 180., 360.-dx, dx)
dists = num.sqrt(dx**2 + (ay-by)**2) deleted = _weed( dists, badnesses, neighborhood, interaction_radius, del_frac=4, max_del=n-nwanted, max_depth=500, depth=0)
kept = num.logical_not(deleted).nonzero()[0] dists_kept = dists[num.meshgrid(kept, kept)] meandists_kept = neighborhood_density(dists_kept, neighborhood) return deleted, meandists_kept
def badnesses_c_mean(badnesses_nslc): # convert stream badnesses to station badnesses by averaging badnesses_nsl = {} for nslc, b in badnesses_nslc.items(): nsl = nslc[:3] badnesses_nsl.setdefault(nsl, []).append(b)
for nsl in list(badnesses_nsl.keys()): this_station_badness = badnesses_nsl[nsl] badnesses_nsl[nsl] = sum(this_station_badness) \ / len(this_station_badness)
return badnesses_nsl
def weed_stations(stations, nwanted, neighborhood=3, default_badness=1.0, badnesses=None, badnesses_ns={}, badnesses_nsl={}, badnesses_nslc={}):
azimuths = num.zeros(len(stations), dtype=num.float) dists = num.zeros(len(stations), dtype=num.float) for ista, sta in enumerate(stations): azimuths[ista] = sta.azimuth dists[ista] = sta.dist_deg
badnesses_nslc_mean_c = badnesses_c_mean(badnesses_nslc) badnesses2 = num.ones(len(stations), dtype=float) for ista, sta in enumerate(stations): nsl = sta.network, sta.station, sta.location if badnesses is not None: b = badnesses[ista] else: b = 1.0 b *= badnesses_ns.get(nsl, 1.0) b *= badnesses_nsl.get(nsl, 1.0) b *= badnesses_nslc_mean_c.get(nsl, 1.0) badnesses2[ista] = b
deleted, meandists_kept = weed( azimuths, dists, badnesses2, nwanted=nwanted, neighborhood=neighborhood)
stations_weeded = [station for (delete, station) in zip(deleted, stations) if not delete]
return stations_weeded, meandists_kept, deleted |