CKKS RNS variant in the threshold example

Library Questions
1

In this example, we see the usage of

CCParams<CryptoContextCKKSRNS> parameters;
    parameters.SetMultiplicativeDepth(3);
    parameters.SetScalingModSize(50);
    parameters.SetBatchSize(batchSize);

    CryptoContext<DCRTPoly> cc = GenCryptoContext(parameters);
    // enable features that you wish to use
    cc->Enable(PKE);
    cc->Enable(KEYSWITCH);
    cc->Enable(LEVELEDSHE);
    cc->Enable(ADVANCEDSHE);
    cc->Enable(MULTIPARTY);

to generate the parameters.

I was reading this paper about the library and wondered,
which of the RNS variants is used in the code above?

2

If I’m not wrong, by default is in mode FLEXIBLEAUTOEXT that is the variant RE-CKKS-DE in this paper Approximate Homomorphic Encryption with Reduced Approximation Error.

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3

As @mmazz mentioned, CKKS defaults to FLEXIBLEAUTOEXT scaling if no specific technique is selected. You can set the scaling technique as follows:

CCParams<CryptoContextCKKSRNS> parameters;
parameters.SetScalingTechnique(<your_preferred_technique>);
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