in pir_server.cpp [17:27]
void PIRServer::preprocess_database() {
if (!is_db_preprocessed_) {
for (uint32_t i = 0; i < db_->size(); i++) {
evaluator_->transform_to_ntt_inplace(
db_->operator[](i), params_.parms_id());
}
is_db_preprocessed_ = true;
}
}