moment

Computes the n-th central moment of a slice.

auto moment(S slice, Order order)
template moment(sumTemplateArgs...)
nothrow @nogc pure nothrow @nogc
auto
moment
(
S
Order
)
(
S slice
,
in Order order
)
if (
isSlice!S
)
auto moment(S slice, Order order, Seed seed)

Members

Functions

moment auto moment(S slice, Order order)
moment deprecated auto moment(S slice, Order order, Seed seed): Undocumented in source. Be warned that the author may not have intended to support it.

Parameters

sumTemplateArgs: template arguments to pass to mir.math.sum (to compute the mean of the slice and the relevant moment)

Examples

2nd central moment of vector

import std.math : approxEqual;
import mir.ndslice.slice : sliced;

static immutable x = [0.0, 1.0, 1.5, 2.0, 3.5, 4.25,
                      2.0, 7.5, 5.0, 1.0, 1.5, 0.0];

// FIXME assert(approxEqual(x.sliced.moment(2), 54.76563 / 12));
assert(approxEqual(x.sliced.moment(2.0), 54.76563 / 12));

2nd central moment of matrix

import mir.ndslice.slice : sliced;
import std.math : approxEqual;

static immutable x = [0.0, 1.0, 1.5, 2.0, 3.5, 4.25,
                      2.0, 7.5, 5.0, 1.0, 1.5, 0.0];

assert(approxEqual(x.sliced(2, 6).moment(2.0), 54.76563 / 12));

Row 2nd central moment of matrix

import mir.ndslice.slice : sliced;
import mir.ndslice.topology : byDim, alongDim, map;
import std.math : approxEqual;

static immutable x = [0.0, 1.0, 1.5, 2.0, 3.5, 4.25,
                      2.0, 7.5, 5.0, 1.0, 1.5, 0.0];
static immutable y = [2.092014, 6.722222];

// Use byDim or alongDim with map to compute moment of row/column.
assert(approxEqual(x.sliced(2, 6).byDim!0.map!(a => a.moment(2.0)), y.sliced));
assert(approxEqual(x.sliced(2, 6).alongDim!1.map!(a => a.moment(2.0)), y.sliced));

moment

Members

Functions

Parameters

Examples

See Also

Meta

Source