# Copyright 2020 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 pyspedas
from pyspedas.tplot_tools import store_data, tinterp
import copy
import logging
[docs]
def subtract(
tvar1,
tvar2,
newname=None,
):
"""
Subtracts two tplot variables. Will interpolate if the two are not on the same time cadence.
Parameters
----------
tvar1 : str
Name of first tplot variable.
tvar2 : int/float
Name of second tplot variable
newname : str
Name of new tvar for added data.
Default: None. If not set, then the data in tvar1 is replaced.
Returns
-------
None
Examples
--------
>>> pyspedas.store_data('a', data={'x':[0,4,8,12,16], 'y':[1,2,3,4,5]})
>>> pyspedas.store_data('c', data={'x':[0,4,8,12,16,19,21], 'y':[1,4,1,7,1,9,1]})
>>> pyspedas.subtract('a','c',newname='a-c')
"""
#interpolate tvars
tv2 = tinterp(tvar1,tvar2)
#separate and subtract data
data1 = pyspedas.tplot_tools.data_quants[tvar1].values
data2 = pyspedas.tplot_tools.data_quants[tv2].values
data = data1 - data2
#store subtracted data
if newname is None:
pyspedas.tplot_tools.data_quants[tvar1].values = data
return tvar1
if 'spec_bins' in pyspedas.tplot_tools.data_quants[tvar1].coords:
store_data(newname, data={'x': pyspedas.tplot_tools.data_quants[tvar1].coords['time'].values, 'y': data, 'v':pyspedas.tplot_tools.data_quants[tvar1].coords['spec_bins'].values})
pyspedas.tplot_tools.data_quants[newname].attrs = copy.deepcopy(pyspedas.tplot_tools.data_quants[tvar1].attrs)
else:
store_data(newname,data={'x': pyspedas.tplot_tools.data_quants[tvar1].coords['time'].values, 'y': data})
pyspedas.tplot_tools.data_quants[newname].attrs = copy.deepcopy(pyspedas.tplot_tools.data_quants[tvar1].attrs)
return newname