Struct ndarray_stats::histogram::Grid

pub struct Grid<A: Ord> { /* fields omitted */ }

A Grid is a partition of a rectangular region of an n-dimensional space—e.g. [a₀, b₀) × ⋯ × [a_n−1, b_n−1)—into a collection of rectangular n-dimensional bins.

The grid is fully determined by its 1-dimensional projections on the coordinate axes. For example, this is a partition that can be represented as a Grid struct:

+---+-------+-+
|   |       | |
+---+-------+-+
|   |       | |
|   |       | |
|   |       | |
|   |       | |
+---+-------+-+

while the next one can't:

+---+-------+-+
|   |       | |
|   +-------+-+
|   |         |
|   |         |
|   |         |
|   |         |
+---+-------+-+

Example:

use ndarray::{Array, array};
use ndarray_stats::{HistogramExt,
                    histogram::{Histogram, Grid, GridBuilder,
                                Edges, Bins, strategies::Auto}};
use noisy_float::types::{N64, n64};

// 1-dimensional observations, as a (n_observations, 1) 2-d matrix
let observations = Array::from_shape_vec(
    (12, 1),
    vec![1, 4, 5, 2, 100, 20, 50, 65, 27, 40, 45, 23],
).unwrap();

// The optimal grid layout is inferred from the data,
// specifying a strategy (Auto in this case)
let grid = GridBuilder::<Auto<usize>>::from_array(&observations).unwrap().build();
let expected_grid = Grid::from(vec![Bins::new(Edges::from(vec![1, 20, 39, 58, 77, 96, 115]))]);
assert_eq!(grid, expected_grid);

let histogram = observations.histogram(grid);

let histogram_matrix = histogram.counts();
// Bins are left inclusive, right exclusive!
let expected = array![4, 3, 3, 1, 0, 1];
assert_eq!(histogram_matrix, expected.into_dyn());

Methods

impl<A: Ord> Grid<A>

pub fn ndim(&self) -> usize

Returns n, the number of dimensions of the region partitioned by the grid.

pub fn shape(&self) -> Vec<usize>

Returns the number of bins along each coordinate axis.

pub fn projections(&self) -> &[Bins<A>]

Returns the grid projections on the coordinate axes as a slice of immutable references.

pub fn index_of<S>(&self, point: &ArrayBase<S, Ix1>) -> Option<Vec<usize>> where
    S: Data<Elem = A>, 

Returns the index of the n-dimensional bin containing the point, if one exists.

Returns None if the point is outside the grid.

Panics if point.len() does not equal self.ndim().

impl<A: Ord + Clone> Grid<A>

pub fn index(&self, index: &[usize]) -> Vec<Range<A>>

Given i=(i_0, ..., i_{n-1}), an n-dimensional index, it returns I_{i_0}x...xI_{i_{n-1}}, an n-dimensional bin, where I_{i_j} is the i_j-th interval on the j-th projection of the grid on the coordinate axes.

Panics if at least one among (i_0, ..., i_{n-1}) is out of bounds on the respective coordinate axis - i.e. if there exists j such that i_j >= self.projections[j].len().

Trait Implementations

impl<A: Eq + Ord> Eq for Grid<A>

impl<A: Clone + Ord> Clone for Grid<A>

fn clone(&self) -> Grid<A>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<A: PartialEq + Ord> PartialEq<Grid<A>> for Grid<A>

fn eq(&self, other: &Grid<A>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Grid<A>) -> bool

This method tests for !=.

impl<A: Ord> From<Vec<Bins<A>>> for Grid<A>

fn from(projections: Vec<Bins<A>>) -> Self

Get a Grid instance from a Vec<Bins<A>>.

The i-th element in Vec<Bins<A>> represents the 1-dimensional projection of the bin grid on the i-th axis.

Alternatively, a Grid can be built directly from data using a GridBuilder.

impl<A: Debug + Ord> Debug for Grid<A>

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.