Source code for openquake.hazardlib.mfd.evenly_discretized

# The Hazard Library
# Copyright (C) 2012-2014, GEM Foundation
#
# This program 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.
#
# This program 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.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
"""
Module :mod:`openquake.hazardlib.mfd.evenly_discretized` defines an evenly
discretized MFD.
"""
from openquake.hazardlib.mfd.base import BaseMFD
from openquake.hazardlib.slots import with_slots


@with_slots
[docs]class EvenlyDiscretizedMFD(BaseMFD): """ Evenly discretized MFD is defined as a precalculated histogram. :param min_mag: Positive float value representing the middle point of the first bin in the histogram. :param bin_width: A positive float value -- the width of a single histogram bin. :param occurrence_rates: The list of non-negative float values representing the actual annual occurrence rates. The resulting histogram has as many bins as this list length. """ MODIFICATIONS = set(('set_mfd',)) __slots__ = 'min_mag bin_width occurrence_rates'.split() def __init__(self, min_mag, bin_width, occurrence_rates): self.min_mag = min_mag self.bin_width = bin_width self.occurrence_rates = occurrence_rates self.check_constraints()
[docs] def check_constraints(self): """ Checks the following constraints: * Bin width is positive. * Occurrence rates list is not empty. * Each number in occurrence rates list is non-negative. * Minimum magnitude is positive. """ if not self.bin_width > 0: raise ValueError('bin width must be positive') if not self.occurrence_rates: raise ValueError('at least one bin must be specified') if not all(value >= 0 for value in self.occurrence_rates): raise ValueError('all occurrence rates must not be negative') if not any(value > 0 for value in self.occurrence_rates): raise ValueError('at least one occurrence rate must be positive') if not self.min_mag >= 0: raise ValueError('minimum magnitude must be non-negative')
[docs] def get_annual_occurrence_rates(self): """ Returns the predefined annual occurrence rates. """ return [(self.min_mag + i * self.bin_width, occurrence_rate) for i, occurrence_rate in enumerate(self.occurrence_rates)]
[docs] def get_min_max_mag(self): """ Returns the minumun and maximum magnitudes """ return self.min_mag, self.min_mag + self. bin_width * ( len(self.occurrence_rates) - 1)
[docs] def modify_set_mfd(self, min_mag, bin_width, occurrence_rates): """ Applies absolute modification of the MFD from the ``min_mag``, ``bin_width`` and ``occurrence_rates`` modification. :param min_mag: Positive float value representing the middle point of the first bin in the histogram. :param bin_width: A positive float value -- the width of a single histogram bin. :param occurrence_rates: The list of non-negative float values representing the actual annual occurrence rates. The resulting histogram has as many bins as this list length. """ self.min_mag = min_mag self.bin_width = bin_width self.occurrence_rates = occurrence_rates self.check_constraints()