Crate iter_num_tools

source ·
Expand description

iter-num-tools

Build Status Rust Documentation Latest Version Code Coverage

This is a collection if iterator extensions that make heavy use of number properties. Mostly extending on Range.

LinSpace

LinSpace is an iterator over a range with a fixed number of values all evenly spaced.

use iter_num_tools::lin_space;

// Count from 1.0 up to and including 5.0, with 5 numbers counted in total
let it = lin_space(1.0..=5.0, 5);
assert!(it.eq([1.0, 2.0, 3.0, 4.0, 5.0]));

// Count from 0.0 up to and excluding 5.0, with 5 numbers counted in total
let it = lin_space(0.0..5.0, 5);
assert!(it.eq([0.0, 1.0, 2.0, 3.0, 4.0]));

GridSpace

GridSpace extends on LinSpace.

use iter_num_tools::grid_space;

// count in 2 dimensions (excluding end points),
// from 0.0 up to 1.0 in the x direction with 2 even steps,
// and 0.0 up to 2.0 in the y direction with 4 even steps
let it = grid_space([0.0, 0.0]..[1.0, 2.0], [2, 4]);
assert!(it.eq([
    [0.0, 0.0], [0.5, 0.0],
    [0.0, 0.5], [0.5, 0.5],
    [0.0, 1.0], [0.5, 1.0],
    [0.0, 1.5], [0.5, 1.5],
]));

// count in 2 dimensions (including end points),
// from 0.0 up to 1.0 in the x direction,
// and 0.0 up to 2.0 in the y direction with 3 even steps in all directions
let it = grid_space([0.0, 0.0]..=[1.0, 2.0], 3);
assert!(it.eq([
    [0.0, 0.0], [0.5, 0.0], [1.0, 0.0],
    [0.0, 1.0], [0.5, 1.0], [1.0, 1.0],
    [0.0, 2.0], [0.5, 2.0], [1.0, 2.0],
]));

Arange

Arange is similar to LinSpace, but instead of a fixed amount of steps, it steps by a fixed amount.

use iter_num_tools::arange;

let it = arange(0.0..2.0, 0.5);
assert!(it.eq([0.0, 0.5, 1.0, 1.5]));
Note

There is no inclusive version of arange. Consider the following

ⓘ
use iter_num_tools::arange;
let it = arange(0.0..=2.1, 0.5);

We would not expect 2.1 to ever be a value that the iterator will ever meet, but the range suggests it should be included. Therefore, no RangeInclusive implementation is provided.

ArangeGrid

ArangeGrid is the same as GridSpace but for Arange instead of LinSpace.

use iter_num_tools::arange_grid;

// count in 2 dimensions,
// from 0.0 up to 1.0 in the x direction,
// and 0.0 up to 2.0 in the y direction,
// stepping by 0.5 each time
let it = arange_grid([0.0, 0.0]..[1.0, 2.0], 0.5);
assert!(it.eq([
    [0.0, 0.0], [0.5, 0.0],
    [0.0, 0.5], [0.5, 0.5],
    [0.0, 1.0], [0.5, 1.0],
    [0.0, 1.5], [0.5, 1.5],
]));

// count in 2 dimensions,
// from 0.0 up to 1.0 in the x direction stepping by 0.5 each time,
// and 0.0 up to 2.0 in the y direction stepping by 1.0 each time
let it = arange_grid([0.0, 0.0]..[1.0, 2.0], [0.5, 1.0]);
assert!(it.eq([
    [0.0, 0.0], [0.5, 0.0],
    [0.0, 1.0], [0.5, 1.0],
]));

LogSpace

LogSpace is similar to LinSpace, but instead of evenly spaced linear steps, it has evenly spaced logarithmic steps.

use iter_num_tools::log_space;
use itertools::zip_eq;

// From 1.0 up to and including 1000.0, taking 4 logarithmic steps
let it = log_space(1.0..=1000.0, 4);
let expected: [f64; 4] = [1.0, 10.0, 100.0, 1000.0];

assert!(zip_eq(it, expected).all(|(x, y)| (x-y).abs() < 1e-10));

// From 1.0 up to 1000.0, taking 3 logarithmic steps
let it = log_space(1.0..1000.0, 3);
let expected: [f64; 3] = [1.0, 10.0, 100.0];

assert!(zip_eq(it, expected).all(|(x, y)| (x-y).abs() < 1e-10));

Traits

  • IterAdapter
    Adds a few extra methods to iterators
  • Product2
    Similar to [std::iter::Product] but doesn’t need turbofish to specify the output
  • Sum2
    Similar to [std::iter::Sum] but doesn’t need turbofish to specify the output

Functions

  • arange
    Create a new iterator over the range, stepping by step each time This allows you to create simple float iterators
  • arange_grid
    Creates a grid space over the range made up of fixed step intervals
  • grid_space
    Creates a linear grid space over range with a fixed number of width and height steps
  • lin_space
    Creates a linear space over range with a fixed number of steps
  • log_space
    Creates a logarithmic space over range with a fixed number of steps

Type Definitions