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BitAdder.hpp
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BitAdder.hpp
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/*
* BitAdder.cpp
*
*/
#ifndef GC_BITADDER_HPP_
#define GC_BITADDER_HPP_
#include "BitAdder.h"
#include <assert.h>
template<class T>
void BitAdder::add(vector<vector<T>>& res, const vector<vector<vector<T>>>& summands,
SubProcessor<T>& proc, int length, ThreadQueues* queues, int player)
{
assert(not summands.empty());
assert(not summands[0].empty());
res.resize(summands[0][0].size());
if (queues)
{
assert(length == T::default_length);
int n_available = queues->find_available();
int n_per_thread = queues->get_n_per_thread(res.size());
vector<vector<array<T, 3>>> triples(n_available);
vector<void*> supplies(n_available);
for (int i = 0; i < n_available; i++)
{
if (T::expensive_triples)
{
supplies[i] = &triples[i];
for (size_t j = 0; j < n_per_thread * summands.size(); j++)
triples[i].push_back(proc.DataF.get_triple(T::default_length));
#ifdef VERBOSE_EDA
cerr << "supplied " << triples[i].size() << endl;
#endif
}
}
ThreadJob job(&res, &summands, T::default_length, player);
int start = queues->distribute_no_setup(job, res.size(), 0, 1,
&supplies);
BitAdder().add(res, summands, start,
summands[0][0].size(), proc, T::default_length);
if (start)
queues->wrap_up(job);
}
else
add(res, summands, 0, res.size(), proc, length);
}
template<class T>
void BitAdder::add(vector<vector<T> >& res,
const vector<vector<vector<T> > >& summands, size_t begin, size_t end,
SubProcessor<T>& proc, int length, int input_begin, const void* supply)
{
#ifdef VERBOSE_EDA
fprintf(stderr, "add bits %lu to %lu\n", begin, end);
#endif
if (input_begin < 0)
input_begin = begin;
int n_bits = summands.size();
for (size_t i = begin; i < end; i++)
res.at(i).resize(n_bits + 1);
size_t n_items = end - begin;
if (supply)
{
#ifdef VERBOSE_EDA
fprintf(stderr, "got supply\n");
#endif
auto& s = *(vector<array<T, 3>>*) supply;
assert(s.size() == n_items * n_bits);
proc.DataF.push_triples(s);
}
if (summands[0].size() > 2)
return multi_add(res, summands, begin, end, proc, length, input_begin);
vector<T> carries(n_items);
vector<T> a(n_items), b(n_items);
auto& protocol = proc.protocol;
for (int i = 0; i < n_bits; i++)
{
assert(summands[i].size() == 2);
assert(summands[i][0].size() >= input_begin + n_items);
assert(summands[i][1].size() >= input_begin + n_items);
for (size_t j = 0; j < n_items; j++)
{
a[j] = summands[i][0][input_begin + j];
b[j] = summands[i][1][input_begin + j];
}
protocol.init_mul();
for (size_t j = 0; j < n_items; j++)
{
res[begin + j][i] = a[j] + b[j] + carries[j];
// full adder using MUX
protocol.prepare_mul(a[j] + b[j], carries[j] + a[j], length);
}
protocol.exchange();
for (size_t j = 0; j < n_items; j++)
carries[j] = a[j] + protocol.finalize_mul(length);
}
for (size_t j = 0; j < n_items; j++)
res[begin + j][n_bits] = carries[j];
}
template<class T>
void BitAdder::multi_add(vector<vector<T> >& res,
const vector<vector<vector<T> > >& summands, size_t begin, size_t end,
SubProcessor<T>& proc, int length, int input_begin)
{
int n_bits = summands.size() + ceil(log2(proc.P.num_players()));
size_t n_items = end - begin;
assert(n_bits > 0);
vector<vector<vector<T>>> my_summands(n_bits);
for (auto& x : my_summands)
{
x.resize(2);
for (auto& y : x)
y.resize(n_items);
}
for (size_t i = 0; i < summands.size(); i++)
for (int j = 0; j < 2; j++)
{
auto& x = my_summands.at(i).at(j);
auto& z = summands.at(i).at(j);
auto y = z.begin() + input_begin;
assert(y + n_items <= z.end());
x.clear();
x.insert(x.begin(), y, y + n_items);
}
vector<vector<T>> my_res(n_items);
for (size_t k = 2; k < summands.at(0).size(); k++)
{
add(my_res, my_summands, 0, n_items, proc, length);
for (size_t i = 0; i < my_summands.size(); i++)
for (size_t j = 0; j < n_items; j++)
my_summands[i][0][j] = my_res[j][i];
for (size_t i = 0; i < summands.size(); i++)
{
auto& z = summands.at(i).at(k);
auto y = z.begin() + input_begin;
assert(y + n_items <= z.end());
auto& x = my_summands.at(i).at(1);
x.clear();
x.insert(x.begin(), y, y + n_items);
}
}
add(res, my_summands, begin, end, proc, length, 0);
}
#endif