Statistics.h File Reference

#include "Stroika/Foundation/StroikaPreComp.h"
#include "Stroika/Foundation/Common/Common.h"
#include "Statistics.inl"

Go to the source code of this file.

Classes
struct	Stroika::Foundation::Math::CommonStatistics< T >

Namespaces
namespace	Stroika::Foundation

Functions
template<typename RESULT_TYPE , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2>
RESULT_TYPE	Stroika::Foundation::Math::Mean (const ITERATOR_OF_T &start, ITERATOR_OF_T2 &&end)
	Mean (average) of a collection of numbers computed.
template<typename RESULT_TYPE , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2, Common::IInOrderComparer< RESULT_TYPE > INORDER_COMPARE_FUNCTION = less<RESULT_TYPE>>
RESULT_TYPE	Stroika::Foundation::Math::Median (const ITERATOR_OF_T &start, ITERATOR_OF_T2 &&end, INORDER_COMPARE_FUNCTION &&compare={})
	Median of a collection of numbers computed.
template<typename RESULT_TYPE , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2>
RESULT_TYPE	Stroika::Foundation::Math::StandardDeviation (const ITERATOR_OF_T &start, ITERATOR_OF_T2 &&end)
	Alias: sd, standard-deviation, stddev.
template<typename T , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2>
CommonStatistics< T >	Stroika::Foundation::Math::ComputeCommonStatistics (const ITERATOR_OF_T &start, ITERATOR_OF_T2 &&end)
	handy aggregation of several common random-variable statistics/measurements.

Detailed Description

Note

Code-Status: Alpha

TODO:

Use std::nth_element from <algorithm> which is O(N): nth_element(a, a + size / 2, a + size); median = a[size/2];

Definition in file Math/Statistics.h.

Function Documentation

Mean()

template<typename RESULT_TYPE , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2>

RESULT_TYPE Stroika::Foundation::Math::Mean	(	const ITERATOR_OF_T &	start,
		ITERATOR_OF_T2 &&	end
	)

Mean (average) of a collection of numbers computed.

Precondition

not empty (or start != end)

Example Usage:

EXPECT_EQ (Mean<double> (vector<int>{1, 3, 5}), 3);

Note

O(N) time complexity

Definition at line 19 of file Math/Statistics.inl.

Median()

template<typename RESULT_TYPE , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2, Common::IInOrderComparer< RESULT_TYPE > INORDER_COMPARE_FUNCTION = less<RESULT_TYPE>>

RESULT_TYPE Stroika::Foundation::Math::Median	(	const ITERATOR_OF_T &	start,
		ITERATOR_OF_T2 &&	end,
		INORDER_COMPARE_FUNCTION &&	compare = {}
	)

Median of a collection of numbers computed.

First template requires explicit RESULT_TYPE argument. Second and third infer it from the iterator/container arguments.

Precondition

not empty

Note

O(N) time complexity

Example Usage:

EXPECT_EQ (Median (vector<int>{1, 3, 5}), 3);

Note

template arguments changed significantly in Stroika v3.0d10

Definition at line 49 of file Math/Statistics.inl.

StandardDeviation()

template<typename RESULT_TYPE , input_iterator ITERATOR_OF_T, sentinel_for< ITERATOR_OF_T > ITERATOR_OF_T2>

RESULT_TYPE Stroika::Foundation::Math::StandardDeviation	(	const ITERATOR_OF_T &	start,
		ITERATOR_OF_T2 &&	end
	)

Alias: sd, standard-deviation, stddev.

Precondition

size of container >= 1

sqrt (sum(mean-di))/(n-1) - 'Bessel's correction'

Example Usage:

EXPECT_TRUE (Math::NearlyEquals (Math::StandardDeviation (vector<double> ({5, 3, 19, 1})), 8.164966, .0001));

See also

https://en.wikipedia.org/wiki/Standard_deviation

Definition at line 90 of file Math/Statistics.inl.