qpms/BUGS.rst

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Known bugs

Wrong factor on B coefficient (single coeff version) -----------------------------(Probably fixed in the "calculator object" versions!) Under Kristensson normalisation (with CS = -1), my code gives B(1,0,n,n)/B(1,0,n,-n) == -(2n)! at (x,y,z) = (x,0,0) (expected plus or minus 1). A-coefficients seem to behave correctly. BUT THE CSPHASE MIGHT BE WRONG ON BOTH SINGLE A AND B (TODO TEST)

Xu's antinormalisation

"Xu's antinormalisation" is broken (most likely in legendre.c and maybe also in qpms_types.h) the plane wave test fails and the spherical wave reconstruction as well (but the translation coefficients match the Xu's tables).

Longitudinal waves

Plane wave decompositions gives wrong value on the longitudinal part. The implementation of the L coefficients OR the longitudinal waves is thus probably wrong.

Scattering result asymmetry

The lattice scattering code (such as finitesqlatzsym-scattery.py) produces asymmetric results where one should not get them, due to the system symmetry.

It seems that the asymmetry appears mostly in the y-direction (i.e. for example the scattering/absorption cross section at k = (kx, ky, kz) is not exactly the same as k = (kx, -ky, kz).

What has been checked (hopefully):
  • The flip operators for electric waves
  • Some weird kind of rounding or other numerical error depending on the position ordering of the matrix (randomized indices give the same asymmetry).
What has not been checked (so well):
  • The x,y,z-flip operators for magnetic waves (i.e. are they really supposet to bejust the same as the operators for electric waves, just with opposite sign?)
  • zplane_pq_y
  • the translation operators

Singular value asymmetry

Similar as the scattering result asymmetry, although not necessarily only in the y-direction?

Overflows etc.

Assertion failed in gaunt_xu for test_vswf_translations.c and high values of LMAX (LMAX=25)

Moreover, the non-normalized legendre functions that are used in translations.c are likely to overflow for even smaller values of l. Therefore TODO: modify translations.c in a way that uses normalised legendre functions everywhere.

Memory management

When compiled with optimizations, I get stack smashing error in qpms_trans_calculator_get_2DFT_longrange_AB_arrays().