# Copyright 2018 Regents of the University of Colorado. All Rights Reserved.
# Released under the MIT license.
# This software was developed at the University of Colorado's Laboratory for Atmospheric and Space Physics.
# Verify current version before use at: https://github.com/MAVENSDC/Pytplot
import pytplot
import numpy as np
import copy
[docs]def derive(tvar,new_tvar=None):
"""
Takes the derivative of the tplot variable.
Parameters:
tvar : str
Name of tplot variable.
new_tvar : str
Name of new tplot variable. If not set, then the data in tvar is replaced.
Returns:
None
Examples:
>>> pytplot.store_data('b', data={'x':[2,5,8,11,14,17,20], 'y':[[1,1,1,1,1,1],[2,2,5,4,1,1],[100,100,3,50,1,1],[4,4,8,58,1,1],[5,5,9,21,1,1],[6,6,2,2,1,1],[7,7,1,6,1,1]]})
>>> pytplot.derive('b','dbdt')
>>> print(pytplot.data_quants['dbdt'].values)
"""
a = pytplot.data_quants[tvar].differentiate('time')
if new_tvar is None:
a.name = tvar
a.attrs = copy.deepcopy(pytplot.data_quants[tvar].attrs)
pytplot.data_quants[tvar] = a
else:
data = {'x':a.coords['time'], 'y':a.values}
for coord in a.coords:
if coord != 'time' and coord != 'spec_bins':
data[coord] = a.coords[coord].values
pytplot.store_data(new_tvar, data=data)
pytplot.data_quants[new_tvar].attrs = copy.deepcopy(pytplot.data_quants[tvar].attrs)
return