SetCustomExcite Error

[qummarzaman1991]

Hi
I am using SetCustomExcite() function in python but I am getting error that object has no attribute 'SetCustomExcite'
I am following the documentation from
https://fasterems.github.io/openEMS-Project/concepts/signals.html
Thanks in advance for your guidance in this regard

[thliebig]

The most important details are missing, which openEMS version on which OS are you using? Octave or Python interface?
Maybe give a short code snippet on how you use it.

[qummarzaman1991]

Thanks for your fast response

Here is snape of my python code

“import os
import numpy as np
import matplotlib.pyplot as plt

os.environ["OPENEMS_INSTALL_PATH"] = r"C:\Users\Qummar\openEMS"

os.environ["PATH"] += os.pathsep + os.environ["OPENEMS_INSTALL_PATH"]

WORK_DIR = os.path.join(os.getcwd(), "test_openEMS")

os.makedirs(WORK_DIR, exist_ok=True)

from openEMS import openEMS
from openEMS.ports import *
from CSXCAD import ContinuousStructure

fdtd = openEMS.openEMS(NrTS=10000)
f0 = 500e6;
T = 1 / f0;
f_str = '(1 - exp(-1 * (t / T^2)) * sin(2 * pi * f0 * t)'
f_str = f_str.replace("T", str(T))
f_str = f_str.replace("f0", str(f0))

f_bytes = f_str.encode("UTF-8")
fdtd.SetCustomExcite(f_bytes, f0 * 2, f0 * 2)”

I Installed openEMS-0.0.36-cp310-cp310-win_amd64.whl file and python is 3.10.18

I am using “Sypder Python IDE” from Anaconda in window environment.

After running this code I got the following error “AttributeError: 'openEMS.openEMS.openEMS' object has no attribute 'SetCustomExcite'”

[thliebig]

The documentation you mentioned is for the latest development build. You are using the last release. I think this is just not jet part of it. Unfortunately building newer Windows version is very hard and I have to find and setup my environment again...
I really recommend you just stick to the normal Gaussian excitation as that is the most efficient?

[qummarzaman1991]

Thanks for your reply but for my task I need to excite the system using custom excitation signal.
Unfortunately Gaussian cannot help a lot.
Is there any other way to excite using custom excitation?

[thliebig]

Well you can switch to the Octave interface instead of python. Or build the latest openEMS on Linux, maybe on WSL2 on Windows.
Alternatively you stick to the Gaussian pulse, make sure it is broadband (which also makes it fast) and thus have the system response for all frequencies and apply signal theory to calculate the expected behavior for any possible time-signal imaginable in post processing.
I think this would be the most efficient approach, but of course it relies heavily on signal theory...

[qummarzaman1991]

Thanks for your nice explanation.
As far as I understand FDTD simulation uses XML generated file.
Would it also possible if some how write external source excitation at XML file before running the FDTD simulation?
I can patch XML file by using some python script.
Thanks in advance for your guidance in this matter