How to interpolate eqp when building BSK?

[hbshu]

Dear developers,

Can yambo interpolate quasi-particle energies obtained on a sparse k-grid onto a dense one? A very dense k-grid is often required in order to converge BSE calculation, but evaluating quasi-particle energies on a dense k-gird is very time-consuming and sometimes impractical due to memory and CPU-time limitation.

Since interpolation is employed to obtain a full band structure, can it also be used to obtain quasi-particle energies on a dense k-grid, thus avoiding calculating them directly?

I ran yambo with "-V qp" and find the following line in input-file:
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KfnQP_N= 1 # [EXTQP BSK BSS] Interpolation neighbours
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I think this parameter is related to interpolation, but don't know its physical meaning. How to specify it?

Best,
hbshu