Possible error in _alg2d_fmp.py

[brijn02]

Dear @paulmueller,

I am currently working on my Bachelor Thesis and I used your code as a basis for different testings. I discovered some inconsistencies in the _alg2d_fmp.py file. The function fourier_map_2d adds a filter to Fcomp to only include the wave with a wavenumber smaller then \sqrt{2} k_m in line 255. However, I believe this conditions isn't applied correctly. The results are now inconsistent for different units (one can apply dimensionless code by compensating for the resolution on the detector or compute the results with units). I believe the mistake is in line 255 and it should be corrected as follows:

Fcomp[np.where(np.sqrt(kinx * * 2 + kiny * * 2) > np.sqrt(2) * km)] = 0

With the square root added the units are correct in that equation. Do you agree?

Thanks in advance!

Best regards,

Bernd

[paulmueller]

What you are writing makes a lot of sense to me!

In the current implementation, it seems like the Fourier space is unnecessarily cropped.

A slightly faster approach would probably be to square km like so:

Fcomp[np.where((kinx**2 + kiny**2) > 2 * km**2)] = 0

Would you like to create a pull request and officially contribute to ODTbrain?

[brijn02]

Dear @paulmueller,

Thank you for your fast response. A contribution would be nice! I will create a pull request tomorrow.

Thanks again.

Best regards,

Bernd