result_type result(Args const &args) const
{
float_type threshold = sum_of_weights(args)
* ( ( is_same<LeftRight, left>::value ) ? args[quantile_probability] : 1. - args[quantile_probability] );
std::size_t n = 0;
Weight sum = Weight(0);
while (sum < threshold)
{
if (n < static_cast<std::size_t>(tail_weights(args).size()))
{
sum += *(tail_weights(args).begin() + n);
n++;
}
else
{
if (std::numeric_limits<result_type>::has_quiet_NaN)
{
return std::numeric_limits<result_type>::quiet_NaN();
}
else
{
std::ostringstream msg;
msg << "index n = " << n << " is not in valid range [0, " << tail(args).size() << ")";
boost::throw_exception(std::runtime_error(msg.str()));
return Sample(0);
}
}
}
// Note that the cached samples of the left are sorted in ascending order,
// whereas the samples of the right tail are sorted in descending order
return *(boost::begin(tail(args)) + n - 1);
}
result_type result(Args const &args) const
{
float_type threshold = sum_of_weights(args)
* ( ( is_same<LeftRight, left>::value ) ? args[quantile_probability] : 1. - args[quantile_probability] );
std::size_t n = 0;
Weight sum = Weight(0);
while (sum < threshold)
{
if (n < static_cast<std::size_t>(tail_weights(args).size()))
{
sum += *(tail_weights(args).begin() + n);
n++;
}
else
{
if (std::numeric_limits<float_type>::has_quiet_NaN)
{
std::fill(
this->tail_means_.begin()
, this->tail_means_.end()
, std::numeric_limits<float_type>::quiet_NaN()
);
}
else
{
std::ostringstream msg;
msg << "index n = " << n << " is not in valid range [0, " << tail(args).size() << ")";
boost::throw_exception(std::runtime_error(msg.str()));
}
}
}
std::size_t num_variates = tail_variate(args).begin()->size();
this->tail_means_.clear();
this->tail_means_.resize(num_variates, Sample(0));
this->tail_means_ = std::inner_product(
tail_variate(args).begin()
, tail_variate(args).begin() + n
, tail_weights(args).begin()
, this->tail_means_
, numeric::functional::plus<array_type const, array_type const>()
, numeric::functional::multiply_and_promote_to_double<VariateType const, Weight const>()
);
float_type factor = sum * ( (is_same<Impl, relative>::value) ? non_coherent_weighted_tail_mean(args) : 1. );
std::transform(
this->tail_means_.begin()
, this->tail_means_.end()
, this->tail_means_.begin()
, std::bind2nd(numeric::functional::divides<typename array_type::value_type const, float_type const>(), factor)
);
return make_iterator_range(this->tail_means_);
}
result_type result(Args const &args) const
{
float_type threshold = sum_of_weights(args)
* ( ( is_same<LeftRight, left>::value ) ? args[quantile_probability] : 1. - args[quantile_probability] );
std::size_t n = 0;
Weight sum = Weight(0);
while (sum < threshold)
{
if (n < static_cast<std::size_t>(tail_weights(args).size()))
{
sum += *(tail_weights(args).begin() + n);
n++;
}
else
{
if (std::numeric_limits<result_type>::has_quiet_NaN)
{
return std::numeric_limits<result_type>::quiet_NaN();
}
else
{
std::ostringstream msg;
msg << "index n = " << n << " is not in valid range [0, " << tail(args).size() << ")";
boost::throw_exception(std::runtime_error(msg.str()));
return result_type(0);
}
}
}
return numeric::average(
std::inner_product(
tail(args).begin()
, tail(args).begin() + n
, tail_weights(args).begin()
, weighted_sample(0)
)
, sum
);
}
result_type result(Args const &args) const
{
if (this->is_dirty_)
{
this->is_dirty_ = false;
float_type threshold = sum_of_weights(args)
* ( ( is_same<LeftRight, left>::value ) ? this->threshold_probability_ : 1. - this->threshold_probability_ );
std::size_t n = 0;
Weight sum = Weight(0);
while (sum < threshold)
{
if (n < static_cast<std::size_t>(tail_weights(args).size()))
{
mu_ += *(tail_weights(args).begin() + n) * *(tail(args).begin() + n);
sigma2_ += *(tail_weights(args).begin() + n) * *(tail(args).begin() + n) * (*(tail(args).begin() + n));
sum += *(tail_weights(args).begin() + n);
n++;
}
else
{
if (std::numeric_limits<float_type>::has_quiet_NaN)
{
return boost::make_tuple(
std::numeric_limits<float_type>::quiet_NaN()
, std::numeric_limits<float_type>::quiet_NaN()
, std::numeric_limits<float_type>::quiet_NaN()
);
}
else
{
std::ostringstream msg;
msg << "index n = " << n << " is not in valid range [0, " << tail(args).size() << ")";
boost::throw_exception(std::runtime_error(msg.str()));
return boost::make_tuple(Sample(0), Sample(0), Sample(0));
}
}
}
float_type u = *(tail(args).begin() + n - 1) * this->sign_;
this->mu_ = this->sign_ * numeric::average(this->mu_, sum);
this->sigma2_ = numeric::average(this->sigma2_, sum);
this->sigma2_ -= this->mu_ * this->mu_;
if (is_same<LeftRight, left>::value)
this->threshold_probability_ = 1. - this->threshold_probability_;
float_type tmp = numeric::average(( this->mu_ - u )*( this->mu_ - u ), this->sigma2_);
float_type xi_hat = 0.5 * ( 1. - tmp );
float_type beta_hat = 0.5 * ( this->mu_ - u ) * ( 1. + tmp );
float_type beta_bar = beta_hat * std::pow(1. - threshold_probability_, xi_hat);
float_type u_bar = u - beta_bar * ( std::pow(1. - threshold_probability_, -xi_hat) - 1.)/xi_hat;
this->fit_parameters_ = boost::make_tuple(u_bar, beta_bar, xi_hat);
}
return this->fit_parameters_;
}