etl/docs/maths/variance.md

title
variance

template <bool Variance_Type, typename TInput, typename TCalc = TInput>
class variance : public etl::unary_function<TInput, void> 

Variance_Type Population or Sample.
TInput The input data type.
TCalc The type to use for internal calculations. By default, equal to TInput.

Enumeration

variance_type
etl::variance_type::Sample     
etl::variance_type::Population 

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variance()

Description
Default constructor.

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template <typename TIterator>
variance(TIterator first, TIterator last)

Description
Construct from an iterator range.

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void add(TInput value1)

Description
Add a value.

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template <typename TIterator>
void add(TIterator first, TIterator last)

Description
Add a range of values.

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void operator()(TInput value)

Description
Add a values.

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template <typename TIterator>
void operator()(TIterator first, TIterator last)

Description
Add a range of values.

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double get_variance() const

Return
The calculated variance for the data.

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operator double() const

Return
The calculated variance for the data.

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size_t count() const

Description
Get the total number added entries.

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void clear()

Description
Clear the variance.

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Example

std::array<char, 10> input
{
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9
};

etl::variance<etl::variance_type::Population, char, int32_t> variance(input.begin(),
                                                                      input.end());

double variance_result;

variance_result = variance; // variance_result  == 8.25