Unexpected galois map index generated by GenLinearTransform(*)

[lilBuffaloEric]

Hi contributors

I found that in ckks GenLinearTransform(), the index of map[int]ringqp.Poly vec will be set to idx += slots ( if idx<0) or idx (if idex>=0) . I guess this is doing idx mod slots . But I think this might potentially generate unexpected rotation index for me when I set logslots < logN -1, i.e. when number of slots required is exactly smaller than the maximum. For example, when idx <0 , the galois element that GenLinearTransform generates is 5^(idx mod slots mod N/2) != 5^(idx mod N/2) , where 5^(idx mod N) is generated by GenRotationKeysForRotations(). Althought the two elements act in the same way, LinearTransformNew will panic when it can't find 5^(idx mod slots mod N) however 5^(idx mod N) is provided.

Not sure if my understanding is correct. But I did encountered this situation these days.

BR

[Pro7ech]

I have opened an issue.