Function lbcrypto::CoeffEncodingCollapse

• Defined in File ckksrns-utils.cpp

Function Documentation

std::vector<std::vector<std::vector<std::complex<double>>>> lbcrypto::CoeffEncodingCollapse(const std::vector<std::complex<double>> &pows, const std::vector<uint32_t> &rotGroup, uint32_t levelBudget, bool flag_i)

Computes the coefficients for the given level budget for the FFT encoding. Needed in EvalLTFFTPrecomputeEncoding.

Parameters

• pows – vector of roots of unity powers.

• rotGroup – rotation group indices to appropriately choose the elements of pows to compute iFFT.

• levelBudget – the user specified budget for levels.

• flag_i – flag that is 0 when we compute the coefficients for conj(U_0^T) and is 1 for conj(i*U_0^T).