139 lines
4.8 KiB
Plaintext
139 lines
4.8 KiB
Plaintext
|
|
{{alias}}( N, c, x, strideX, out, strideOut )
|
|
Computes the mean and standard deviation of a double-precision floating-
|
|
point strided array using a two-pass algorithm.
|
|
|
|
The `N` and `stride` parameters determine which elements are accessed at
|
|
runtime.
|
|
|
|
Indexing is relative to the first index. To introduce an offset, use a typed
|
|
array view.
|
|
|
|
If `N <= 0`, the function returns a mean and standard deviation equal to
|
|
`NaN`.
|
|
|
|
Parameters
|
|
----------
|
|
N: integer
|
|
Number of indexed elements.
|
|
|
|
c: number
|
|
Degrees of freedom adjustment. Setting this parameter to a value other
|
|
than `0` has the effect of adjusting the divisor during the calculation
|
|
of the standard deviation according to `N - c` where `c` corresponds to
|
|
the provided degrees of freedom adjustment. When computing the standard
|
|
deviation of a population, setting this parameter to `0` is the standard
|
|
choice (i.e., the provided array contains data constituting an entire
|
|
population). When computing the corrected sample standard deviation,
|
|
setting this parameter to `1` is the standard choice (i.e., the provided
|
|
array contains data sampled from a larger population; this is commonly
|
|
referred to as Bessel's correction).
|
|
|
|
x: Float64Array
|
|
Input array.
|
|
|
|
strideX: integer
|
|
Index increment for `x`.
|
|
|
|
out: Float64Array
|
|
Output array.
|
|
|
|
strideOut: integer
|
|
Index increment for `out`.
|
|
|
|
Returns
|
|
-------
|
|
out: Float64Array
|
|
Output array.
|
|
|
|
Examples
|
|
--------
|
|
// Standard Usage:
|
|
> var x = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 2.0 ] );
|
|
> var out = new {{alias:@stdlib/array/float64}}( 2 );
|
|
> {{alias}}( x.length, 1, x, 1, out, 1 )
|
|
<Float64Array>[ ~0.3333, ~2.0817 ]
|
|
|
|
// Using `N` and `stride` parameters:
|
|
> x = new {{alias:@stdlib/array/float64}}( [ -2.0, 1.0, 1.0, -5.0, 2.0, -1.0 ] );
|
|
> out = new {{alias:@stdlib/array/float64}}( 2 );
|
|
> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
|
> {{alias}}( N, 1, x, 2, out, 1 )
|
|
<Float64Array>[ ~0.3333, ~2.0817 ]
|
|
|
|
// Using view offsets:
|
|
> var x0 = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 3.0, 2.0, 5.0, 1.0 ] );
|
|
> var x1 = new {{alias:@stdlib/array/float64}}( x0.buffer, x0.BYTES_PER_ELEMENT*1 );
|
|
> N = {{alias:@stdlib/math/base/special/floor}}( x0.length / 2 );
|
|
> out = new {{alias:@stdlib/array/float64}}( 2 );
|
|
> {{alias}}( N, 1, x1, 2, out, 1 )
|
|
<Float64Array>[ ~0.3333, ~2.0817 ]
|
|
|
|
{{alias}}.ndarray( N, c, x, strideX, offsetX, out, strideOut, offsetOut )
|
|
Computes the mean and standard deviation of a double-precision floating-
|
|
point strided array using a two-pass algorithm and alternative indexing
|
|
semantics.
|
|
|
|
While typed array views mandate a view offset based on the underlying
|
|
buffer, the `offset` parameter supports indexing semantics based on a
|
|
starting index.
|
|
|
|
Parameters
|
|
----------
|
|
N: integer
|
|
Number of indexed elements.
|
|
|
|
c: number
|
|
Degrees of freedom adjustment. Setting this parameter to a value other
|
|
than `0` has the effect of adjusting the divisor during the calculation
|
|
of the standard deviation according to `N - c` where `c` corresponds to
|
|
the provided degrees of freedom adjustment. When computing the standard
|
|
deviation of a population, setting this parameter to `0` is the standard
|
|
choice (i.e., the provided array contains data constituting an entire
|
|
population). When computing the corrected sample standard deviation,
|
|
setting this parameter to `1` is the standard choice (i.e., the provided
|
|
array contains data sampled from a larger population; this is commonly
|
|
referred to as Bessel's correction).
|
|
|
|
x: Float64Array
|
|
Input array.
|
|
|
|
strideX: integer
|
|
Index increment for `x`.
|
|
|
|
offsetX: integer
|
|
Starting index for `x`.
|
|
|
|
out: Float64Array
|
|
Output array.
|
|
|
|
strideOut: integer
|
|
Index increment for `out`.
|
|
|
|
offsetOut: integer
|
|
Starting index for `out`.
|
|
|
|
Returns
|
|
-------
|
|
out: Float64Array
|
|
Output array.
|
|
|
|
Examples
|
|
--------
|
|
// Standard Usage:
|
|
> var x = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 2.0 ] );
|
|
> var out = new {{alias:@stdlib/array/float64}}( 2 );
|
|
> {{alias}}.ndarray( x.length, 1, x, 1, 0, out, 1, 0 )
|
|
<Float64Array>[ ~0.3333, ~2.0817 ]
|
|
|
|
// Using offset parameter:
|
|
> var x = new {{alias:@stdlib/array/float64}}( [ 1.0, -2.0, 3.0, 2.0, 5.0, 1.0 ] );
|
|
> var N = {{alias:@stdlib/math/base/special/floor}}( x.length / 2 );
|
|
> out = new {{alias:@stdlib/array/float64}}( 2 );
|
|
> {{alias}}.ndarray( N, 1, x, 2, 1, out, 1, 0 )
|
|
<Float64Array>[ ~0.3333, ~2.0817 ]
|
|
|
|
See Also
|
|
--------
|
|
|