| [section:dist_ref Statistical Distributions Reference] |
| |
| [include distributions/non_members.qbk] |
| |
| [section:dists Distributions] |
| |
| [include distributions/bernoulli.qbk] |
| [include distributions/beta.qbk] |
| [include distributions/binomial.qbk] |
| [include distributions/cauchy.qbk] |
| [include distributions/chi_squared.qbk] |
| [include distributions/exponential.qbk] |
| [include distributions/extreme_value.qbk] |
| [include distributions/fisher.qbk] |
| [include distributions/gamma.qbk] |
| [include distributions/inverse_chi_squared.qbk] |
| [include distributions/inverse_gamma.qbk] |
| [include distributions/hypergeometric.qbk] |
| [include distributions/laplace.qbk] |
| [include distributions/logistic.qbk] |
| [include distributions/lognormal.qbk] |
| [include distributions/negative_binomial.qbk] |
| [include distributions/nc_beta.qbk] |
| [include distributions/nc_chi_squared.qbk] |
| [include distributions/nc_f.qbk] |
| [include distributions/nc_t.qbk] |
| [include distributions/normal.qbk] |
| [include distributions/pareto.qbk] |
| [include distributions/poisson.qbk] |
| [include distributions/rayleigh.qbk] |
| [include distributions/students_t.qbk] |
| [include distributions/triangular.qbk] |
| [include distributions/weibull.qbk] |
| [include distributions/uniform.qbk] |
| |
| [endsect][/section:dists Distributions] |
| |
| [include dist_algorithms.qbk] |
| |
| [endsect][/section:dist_ref Statistical Distributions and Functions Reference] |
| |
| |
| [section:future Extras/Future Directions] |
| |
| [h4 Adding Additional Location and Scale Parameters] |
| |
| In some modelling applications we require a distribution with a specific |
| location and scale: |
| often this equates to a specific mean and standard deviation, although for many |
| distributions the relationship between these properties and the location and |
| scale parameters are non-trivial. |
| See [@http://www.itl.nist.gov/div898/handbook/eda/section3/eda364.htm http://www.itl.nist.gov/div898/handbook/eda/section3/eda364.htm] for more |
| information. |
| |
| The obvious way to handle this is via an adapter template: |
| |
| template <class Dist> |
| class scaled_distribution |
| { |
| scaled_distribution( |
| const Dist dist, |
| typename Dist::value_type location, |
| typename Dist::value_type scale = 0); |
| }; |
| |
| Which would then have its own set of overloads for the non-member accessor functions. |
| |
| [h4 An "any_distribution" class] |
| |
| It would be fairly trivial to add a distribution object that virtualises |
| the actual type of the distribution, and can therefore hold "any" object |
| that conforms to the conceptual requirements of a distribution: |
| |
| template <class RealType> |
| class any_distribution |
| { |
| public: |
| template <class Distribution> |
| any_distribution(const Distribution& d); |
| }; |
| |
| // Get the cdf of the underlying distribution: |
| template <class RealType> |
| RealType cdf(const any_distribution<RealType>& d, RealType x); |
| // etc.... |
| |
| Such a class would facilitate the writing of non-template code that can |
| function with any distribution type. It's not clear yet whether there is a |
| compelling use case though. Possibly tests for goodness of fit might |
| provide such a use case: this needs more investigation. |
| |
| [h4 Higher Level Hypothesis Tests] |
| |
| Higher-level tests roughly corresponding to the |
| [@http://documents.wolfram.com/mathematica/Add-onsLinks/StandardPackages/Statistics/HypothesisTests.html Mathematica Hypothesis Tests] |
| package could be added reasonably easily, for example: |
| |
| template <class InputIterator> |
| typename std::iterator_traits<InputIterator>::value_type |
| test_equal_mean( |
| InputIterator a, |
| InputIterator b, |
| typename std::iterator_traits<InputIterator>::value_type expected_mean); |
| |
| Returns the probability that the data in the sequence [a,b) has the mean |
| /expected_mean/. |
| |
| [h4 Integration With Statistical Accumulators] |
| |
| [@http://boost-sandbox.sourceforge.net/libs/accumulators/doc/html/index.html |
| Eric Niebler's accumulator framework] - also work in progress - provides the means |
| to calculate various statistical properties from experimental data. There is an |
| opportunity to integrate the statistical tests with this framework at some later date: |
| |
| // Define an accumulator, all required statistics to calculate the test |
| // are calculated automatically: |
| accumulator_set<double, features<tag::test_expected_mean> > acc(expected_mean=4); |
| // Pass our data to the accumulator: |
| acc = std::for_each(mydata.begin(), mydata.end(), acc); |
| // Extract the result: |
| double p = probability(acc); |
| |
| [endsect][/section:future Extras Future Directions] |
| |
| [/ dist_reference.qbk |
| Copyright 2006, 2010 John Maddock and Paul A. Bristow. |
| Distributed under the Boost Software License, Version 1.0. |
| (See accompanying file LICENSE_1_0.txt or copy at |
| http://www.boost.org/LICENSE_1_0.txt). |
| ] |
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