examples.h

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license.

#pragma once

#include <cstddef>
#include <iostream>
#include <fstream>
#include <iomanip>
#include <vector>
#include <string>
#include <chrono>
#include <random>
#include <thread>
#include <mutex>
#include <memory>
#include <limits>
#include <algorithm>
#include <numeric>
#include "seal/seal.h"

void example_bfv_basics();

void example_encoders();

void example_levels();

void example_ckks_basics();

void example_rotation();

void example_performance_test();

/*
Helper function: Prints the name of the example in a fancy banner.
*/
inline void print_example_banner(std::string title)
{
    if (!title.empty())
    {
        std::size_t title_length = title.length();
        std::size_t banner_length = title_length + 2 * 10;
        std::string banner_top = "+" + std::string(banner_length - 2, '-') + "+";
        std::string banner_middle =
            "|" + std::string(9, ' ') + title + std::string(9, ' ') + "|";

        std::cout << std::endl
            << banner_top << std::endl
            << banner_middle << std::endl
            << banner_top << std::endl;
    }
}

/*
Helper function: Prints the parameters in a SEALContext.
*/
inline void print_parameters(std::shared_ptr<seal::SEALContext> context)
{
    // Verify parameters
    if (!context)
    {
        throw std::invalid_argument("context is not set");
    }
    auto &context_data = *context->key_context_data();

    /*
    Which scheme are we using?
    */
    std::string scheme_name;
    switch (context_data.parms().scheme())
    {
    case seal::scheme_type::BFV:
        scheme_name = "BFV";
        break;
    case seal::scheme_type::CKKS:
        scheme_name = "CKKS";
        break;
    default:
        throw std::invalid_argument("unsupported scheme");
    }
    std::cout << "/" << std::endl;
    std::cout << "| Encryption parameters :" << std::endl;
    std::cout << "|   scheme: " << scheme_name << std::endl;
    std::cout << "|   poly_modulus_degree: " <<
        context_data.parms().poly_modulus_degree() << std::endl;

    /*
    Print the size of the true (product) coefficient modulus.
    */
    std::cout << "|   coeff_modulus size: ";
    std::cout << context_data.total_coeff_modulus_bit_count() << " (";
    auto coeff_modulus = context_data.parms().coeff_modulus();
    std::size_t coeff_mod_count = coeff_modulus.size();
    for (std::size_t i = 0; i < coeff_mod_count - 1; i++)
    {
        std::cout << coeff_modulus[i].bit_count() << " + ";
    }
    std::cout << coeff_modulus.back().bit_count();
    std::cout << ") bits" << std::endl;

    /*
    For the BFV scheme print the plain_modulus parameter.
    */
    if (context_data.parms().scheme() == seal::scheme_type::BFV)
    {
        std::cout << "|   plain_modulus: " << context_data.
            parms().plain_modulus().value() << std::endl;
    }

    std::cout << "\\" << std::endl;
}

/*
Helper function: Prints the `parms_id' to std::ostream.
*/
inline std::ostream &operator <<(std::ostream &stream, seal::parms_id_type parms_id)
{
    /*
    Save the formatting information for std::cout.
    */
    std::ios old_fmt(nullptr);
    old_fmt.copyfmt(std::cout);

    stream << std::hex << std::setfill('0')
        << std::setw(16) << parms_id[0] << " "
        << std::setw(16) << parms_id[1] << " "
        << std::setw(16) << parms_id[2] << " "
        << std::setw(16) << parms_id[3] << " ";

    /*
    Restore the old std::cout formatting.
    */
    std::cout.copyfmt(old_fmt);

    return stream;
}

/*
Helper function: Prints a vector of floating-point values.
*/
template<typename T>
inline void print_vector(std::vector<T> vec, std::size_t print_size = 4, int prec = 3)
{
    /*
    Save the formatting information for std::cout.
    */
    std::ios old_fmt(nullptr);
    old_fmt.copyfmt(std::cout);

    std::size_t slot_count = vec.size();

    std::cout << std::fixed << std::setprecision(prec);
    std::cout << std::endl;
    if(slot_count <= 2 * print_size)
    {
        std::cout << "    [";
        for (std::size_t i = 0; i < slot_count; i++)
        {
            std::cout << " " << vec[i] << ((i != slot_count - 1) ? "," : " ]\n");
        }
    }
    else
    {
        vec.resize(std::max(vec.size(), 2 * print_size));
        std::cout << "    [";
        for (std::size_t i = 0; i < print_size; i++)
        {
            std::cout << " " << vec[i] << ",";
        }
        if(vec.size() > 2 * print_size)
        {
            std::cout << " ...,";
        }
        for (std::size_t i = slot_count - print_size; i < slot_count; i++)
        {
            std::cout << " " << vec[i] << ((i != slot_count - 1) ? "," : " ]\n");
        }
    }
    std::cout << std::endl;

    /*
    Restore the old std::cout formatting.
    */
    std::cout.copyfmt(old_fmt);
}


/*
Helper function: Prints a matrix of values.
*/
template<typename T>
inline void print_matrix(std::vector<T> matrix, std::size_t row_size)
{
    /*
    We're not going to print every column of the matrix (there are 2048). Instead
    print this many slots from beginning and end of the matrix.
    */
    std::size_t print_size = 5;

    std::cout << std::endl;
    std::cout << "    [";
    for (std::size_t i = 0; i < print_size; i++)
    {
        std::cout << std::setw(3) << std::right << matrix[i] << ",";
    }
    std::cout << std::setw(3) << " ...,";
    for (std::size_t i = row_size - print_size; i < row_size; i++)
    {
        std::cout << std::setw(3) << matrix[i]
            << ((i != row_size - 1) ? "," : " ]\n");
    }
    std::cout << "    [";
    for (std::size_t i = row_size; i < row_size + print_size; i++)
    {
        std::cout << std::setw(3) << matrix[i] << ",";
    }
    std::cout << std::setw(3) << " ...,";
    for (std::size_t i = 2 * row_size - print_size; i < 2 * row_size; i++)
    {
        std::cout << std::setw(3) << matrix[i]
            << ((i != 2 * row_size - 1) ? "," : " ]\n");
    }
    std::cout << std::endl;
};

/*
Helper function: Print line number.
*/
inline void print_line(int line_number)
{
    std::cout << "Line " << std::setw(3) << line_number << " --> ";
}