Question: Multiply imaginary i for CKKS without increase the scale of the ciphertext

[guiming-shi]

I find the imult function in HEAAN library but not this library, this realize the function
ciphertext * i, e.g., ([3, 4, -2i, i] * i = [3i, 4i, 2, -1]) without increase the scale of the
ciphertext, is this function will be realized? thanks.

[lehugueni]

It's automatically taken care of in lattigo. If op1 in the Mul function (or any variant) is a gaussian integer, the scale is not increased.

[guiming-shi]

Thanks