49 lines
1.2 KiB
Plaintext
49 lines
1.2 KiB
Plaintext
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{{alias}}( W[, mean] )
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Returns an accumulator function which incrementally computes a moving
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unbiased sample variance.
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The `W` parameter defines the number of values over which to compute the
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moving unbiased sample variance.
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If provided a value, the accumulator function returns an updated moving
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unbiased sample variance. If not provided a value, the accumulator function
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returns the current moving unbiased sample variance.
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As `W` values are needed to fill the window buffer, the first `W-1` returned
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values are calculated from smaller sample sizes. Until the window is full,
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each returned value is calculated from all provided values.
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Parameters
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----------
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W: integer
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Window size.
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mean: number (optional)
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Known mean.
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Returns
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-------
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acc: Function
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Accumulator function.
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Examples
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--------
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> var accumulator = {{alias}}( 3 );
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> var s2 = accumulator()
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null
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> s2 = accumulator( 2.0 )
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0.0
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> s2 = accumulator( -5.0 )
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24.5
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> s2 = accumulator( 3.0 )
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19.0
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> s2 = accumulator( 5.0 )
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28.0
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> s2 = accumulator()
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28.0
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See Also
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--------
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