simpeg.electromagnetics.time_domain.sources.RawWaveform#

class simpeg.electromagnetics.time_domain.sources.RawWaveform(off_time=0.0, waveform_function=None, **kwargs)[source]#

Bases: BaseWaveform

A waveform you can define. You need to provide a waveform_function that returns the waveform evaluated at a given time. This can be used, for example if you would like to interpolate between points specified in a waveform file.

Parameters:
off_timefloat, default: 0.0

time at which the transmitter is turned off in units of seconds (default is 0s)

waveform_function: function

Examples

In this example, we define a saw-tooth waveform

>>> import matplotlib.pyplot as plt
>>> import numpy as np
>>> from simpeg.electromagnetics import time_domain as tdem

>>> def my_waveform(t):
>>>     period = 1e-2
>>>     quarter_period = period / 4
>>>     t_cycle = np.mod(t, period)
>>>     if t_cycle <= quarter_period:
>>>         return t_cycle / quarter_period
>>>     elif (t_cycle > quarter_period) & (t_cycle <= 3*quarter_period):
>>>         return -t_cycle / quarter_period + 2
>>>     elif t_cycle > 3*quarter_period:
>>>         return t_cycle / quarter_period - 4

>>> times = np.linspace(0, 1e-2, 1000)
>>> waveform = tdem.sources.RawWaveform(waveform_function=my_waveform)
>>> plt.plot(times, [waveform.eval(t) for t in times])
>>> plt.show()

(Source code, png, pdf)

../../../_images/simpeg-electromagnetics-time_domain-sources-RawWaveform-1.png

Attributes

epsilon

Window of time within which the waveform is considered on

has_initial_fields

Whether the waveform has initial fields.

off_time

Off-time

waveform_function

Function handle for a custom waveform

Methods

eval(time)

Evaluate current waveform at a given time

eval_deriv(time)

Evaluate the time derivative of the linear ramp-off waveform at given times

Galleries and Tutorials using simpeg.electromagnetics.time_domain.sources.RawWaveform#

EM: TDEM: 1D: Inversion with VTEM waveform

EM: TDEM: 1D: Inversion with VTEM waveform