Hi everyone,

I am currently trying to write my own HDF5 input file for the C++ code and I only have a problem with ddx_k_shift_pos_r and its family (ddx_k_shift_neg_r, ddy_k_shift_pos, ddy_k_shift_neg etc...).

How to compute it? I have only found this formula in the matlab code (in kspaceFirstOrder3D.m):

ddy_k_shift_pos = ifftshift( 1i*kgrid.ky_vec );

ddy_k_shift_neg = ifftshift( 1i*kgrid.ky_vec );

More precisely, I have 3 questions:

- it does not give the same result as when I read an input file created with kspaceFirstOrder_saveToDisk.m what makes me feel that my formula is not the right one, but I don't see anything else in the code...

- what is the difference between ..._neg and ..._pos?

- why is there a ..._r suffix along the x dimension? Is the formula different?

Sorry for the question, but I have fought with this the whole afternoon.

Regards,

Anthony