tools::gamma_picker Class Reference

#include <wallet2.h>

Public Member Functions
uint64_t	pick ()
	gamma_picker (const std::vector< uint64_t > &rct_offsets)
	gamma_picker (const std::vector< uint64_t > &rct_offsets, double shape, double scale)

Detailed Description

Definition at line 87 of file wallet2.h.

Constructor & Destructor Documentation

gamma_picker() [1/2]

tools::gamma_picker::gamma_picker

(

const std::vector< uint64_t > &

rct_offsets

)

Definition at line 1010 of file wallet2.cpp.

: gamma_picker(rct_offsets, GAMMA_SHAPE, GAMMA_SCALE) {}

gamma_picker() [2/2]

tools::gamma_picker::gamma_picker	(	const std::vector< uint64_t > &	rct_offsets,
		double	shape,
		double	scale
	)

Definition at line 995 of file wallet2.cpp.

                                                                                            :
    rct_offsets(rct_offsets)
{
  gamma = std::gamma_distribution<double>(shape, scale);
  THROW_WALLET_EXCEPTION_IF(rct_offsets.size() <= ETN_DEFAULT_TX_SPENDABLE_AGE_V8, error::wallet_internal_error, "Bad offset calculation");
  const size_t blocks_in_a_year = 86400 * 365 / DIFFICULTY_TARGET_V6;
  const size_t blocks_to_consider = std::min<size_t>(rct_offsets.size(), blocks_in_a_year);
  const size_t outputs_to_consider = rct_offsets.back() - (blocks_to_consider < rct_offsets.size() ? rct_offsets[rct_offsets.size() - blocks_to_consider - 1] : 0);
  begin = rct_offsets.data();
  end = rct_offsets.data() + rct_offsets.size() - ETN_DEFAULT_TX_SPENDABLE_AGE_V8;
  num_rct_outputs = *(end - 1);
  THROW_WALLET_EXCEPTION_IF(num_rct_outputs == 0, error::wallet_internal_error, "No rct outputs");
  average_output_time = DIFFICULTY_TARGET_V6 * blocks_to_consider / outputs_to_consider; // this assumes constant target over the whole rct range
};

Member Function Documentation

pick()

uint64_t tools::gamma_picker::pick

(

)

Definition at line 1012 of file wallet2.cpp.

{
  double x = gamma(engine);
  x = exp(x);
  uint64_t output_index = x / average_output_time;
  if (output_index >= num_rct_outputs)
    return std::numeric_limits<uint64_t>::max(); // bad pick
  output_index = num_rct_outputs - 1 - output_index;
 
  const uint64_t *it = std::lower_bound(begin, end, output_index);
  THROW_WALLET_EXCEPTION_IF(it == end, error::wallet_internal_error, "output_index not found");
  uint64_t index = std::distance(begin, it);
 
  const uint64_t first_rct = index == 0 ? 0 : rct_offsets[index - 1];
  const uint64_t n_rct = rct_offsets[index] - first_rct;
  if (n_rct == 0)
    return std::numeric_limits<uint64_t>::max(); // bad pick
  MTRACE("Picking 1/" << n_rct << " in block " << index);
  return first_rct + crypto::rand_idx(n_rct);
};

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The documentation for this class was generated from the following files:

• /home/abuild/rpmbuild/BUILD/electroneum-4.0.0.0/src/wallet/wallet2.h
• /home/abuild/rpmbuild/BUILD/electroneum-4.0.0.0/src/wallet/wallet2.cpp