Struct igraph_psumtree_t 

pub struct igraph_psumtree_t { /* private fields */ }

Implementations

impl igraph_psumtree_t

pub fn new(size: usize) -> Result<Self>

Creates a tree with size items, all of weight zero (igraph_psumtree_init).

Errors

ErrorKind::InvalidValue if size is zero.

pub fn from_weights(weights: &[f64]) -> Result<Self>

Creates a tree whose items have the given weights.

Errors

ErrorKind::InvalidValue if weights is empty, or a weight is negative or not finite.

pub fn len(&self) -> usize

The number of items (igraph_psumtree_size).

pub fn is_empty(&self) -> bool

Whether the tree has no items (never true for a successfully created tree).

pub fn get(&self, index: usize) -> Option<f64>

The weight of item index, or None if out of bounds (igraph_psumtree_get). O(1).

pub fn weights(&self) -> Vec<f64>

The weights of all the items, in order.

pub fn sum(&self) -> f64

The total weight of the items (igraph_psumtree_sum). O(1).

pub fn update(&mut self, index: usize, weight: f64) -> Result<()>

Sets the weight of item index (igraph_psumtree_update). O(log n).

Errors

ErrorKind::InvalidValue if index is out of bounds or weight is negative, infinite or NaN.

pub fn reset(&mut self)

Resets all the weights to zero (igraph_psumtree_reset).

pub fn search(&self, value: f64) -> Result<usize>

Finds the item whose cumulative weight interval contains value (igraph_psumtree_search). O(log n).

Precisely, it returns the lowest index i such that the total weight of the items before i is <= value and adding the weight of i makes it > value. Items of weight zero are therefore never returned.

Errors

ErrorKind::InvalidValue unless 0 <= value < self.sum() (in particular when all weights are zero).

pub fn sample(&self) -> Option<usize>

Draws an item with probability proportional to its weight, using the thread’s default random number generator; None if all weights are zero. O(log n).

Examples

use igraph::{misc::PsumTree, prelude::*};

rng::seed(3)?;
let tree = PsumTree::from_weights(&[0.0, 1.0, 0.0])?;
assert!((0..100).all(|_| tree.sample() == Some(1)));

Trait Implementations

impl Clone for igraph_psumtree_t

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for igraph_psumtree_t

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

Formats the value using the given formatter.

impl Drop for igraph_psumtree_t

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.