# This file is part of OpenDrift.
#
# OpenDrift is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 2
#
# OpenDrift 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with OpenDrift. If not, see <https://www.gnu.org/licenses/>.
#
# Copyright 2015, Knut-Frode Dagestad, MET Norway
from datetime import datetime
import numpy as np
from opendrift.readers.basereader import BaseReader, ContinuousReader
[docs]
class Reader(BaseReader, ContinuousReader):
'''Returning values oscillating in time with given amplitude and period'''
def __init__(self, variable, amplitude, period_seconds=3600*24,
phase=0, zero_time=datetime(2017, 1, 1, 0)):
'''init with '''
self.variables = [variable]
self.amplitude = amplitude
self.period_seconds = period_seconds
self.zero_time = zero_time
self.proj4 = '+proj=latlong +datum=WGS84'
self.xmin = -180
self.xmax = 180
self.ymin = -90
self.ymax = 90
self.start_time = None
self.end_time = None
self.time_step = None
self.name = 'oscillating_reader'
# Run constructor of parent Reader class
super(Reader, self).__init__()
[docs]
def get_variables(self, requestedVariables, time=None,
x=None, y=None, z=None):
variables = {'time': time, 'x': x, 'y': y, 'z': z}
phase = ((time - self.zero_time).total_seconds()/
self.period_seconds)*np.pi
value = self.amplitude*np.sin(phase)
variables[self.variables[0]] = value*np.ones(x.shape)
return variables