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Revert back to outputs_per_second + use logic error on output miss

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j-berman 2021-09-30 01:29:29 -07:00 committed by Lee *!* Clagett
parent a9794d39b8
commit 25356a91e1
2 changed files with 6 additions and 10 deletions
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14
src/util/gamma_picker.cpp
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@ -51,7 +51,7 @@ namespace lws
gamma_picker::gamma_picker(std::vector<std::uint64_t> offsets_in, double shape, double scale)
: rct_offsets(std::move(offsets_in)),
gamma(shape, scale),
seconds_per_output(0)
outputs_per_second(0)
{
if (!rct_offsets.empty())
{
@ -61,11 +61,8 @@ namespace lws
const std::size_t outputs_to_consider = rct_offsets.back() - initial;
static_assert(0 < DIFFICULTY_TARGET_V2, "block target time cannot be zero");
// match wallet2's integer truncation implementation to avoid creating distinct anonymity puddles
// this assumes constant target over the whole rct range
seconds_per_output = DIFFICULTY_TARGET_V2 * blocks_to_consider / outputs_to_consider;
if (seconds_per_output == 0)
seconds_per_output = double(DIFFICULTY_TARGET_V2 * blocks_to_consider) / outputs_to_consider;
outputs_per_second = outputs_to_consider / double(DIFFICULTY_TARGET_V2 * blocks_to_consider);
}
}
@ -95,21 +92,20 @@ namespace lws
{
double output_age_in_seconds = std::exp(gamma(engine));
// match wallet2 implementation to avoid creating distinct anonymity pools
// shift output back by unlock time to apply distribution from chain tip
if (output_age_in_seconds > defaut_unlock_time)
output_age_in_seconds -= defaut_unlock_time;
else
output_age_in_seconds = crypto::rand_idx(recent_spend_window);
std::uint64_t output_index = output_age_in_seconds / seconds_per_output;
std::uint64_t output_index = output_age_in_seconds * outputs_per_second;
if (num_rct_outputs <= output_index)
continue; // gamma selected older than blockchain height (rare)
output_index = num_rct_outputs - 1 - output_index;
const auto selection = std::lower_bound(offsets().begin(), end, output_index);
if (selection == end)
throw std::runtime_error{"Unable to select random output - output not found"};
throw std::logic_error{"Unable to select random output - output not found in range (should never happen)"};
const std::uint64_t first_rct = offsets().begin() == selection ? 0 : *(selection - 1);
const std::uint64_t n_rct = *selection - first_rct;
@ -117,7 +113,7 @@ namespace lws
return first_rct + crypto::rand_idx(n_rct);
// block had zero outputs (miner didn't collect XMR?)
}
throw std::runtime_error{"Unable to select random output in spendable range using gamma distribution after 1,024 attempts"};
throw std::runtime_error{"Unable to select random output in spendable range using gamma distribution after 100 attempts"};
}
std::vector<std::uint64_t> gamma_picker::take_offsets()

2
src/util/gamma_picker.h
View file

@ -36,7 +36,7 @@ namespace lws
{
std::vector<uint64_t> rct_offsets;
std::gamma_distribution<double> gamma;
double seconds_per_output;
double outputs_per_second;
gamma_picker(const gamma_picker&) = default; // force explicit usage of `clone()` to copy.
public: