@stdlib/iter-linspace NPM

iterLinspace

Create an iterator which returns evenly spaced numbers over a specified interval.

Installation

npm install @stdlib/iter-linspace

Usage

var iterLinspace = require( '@stdlib/iter-linspace' );

iterLinspace( start, stop[, N] )

Returns an iterator which returns evenly spaced numbers over a specified interval.

var it = iterLinspace( 0, 99 );
// returns <Object>

var v = it.next().value;
// returns 0

v = it.next().value;
// returns 1

v = it.next().value;
// returns 2

// ...

The returned iterator protocol-compliant object has the following properties:

next: function which returns an iterator protocol-compliant object containing the next iterated value (if one exists) assigned to a value property and a done property having a boolean value indicating whether the iterator is finished.
return: function which closes an iterator and returns a single (optional) argument in an iterator protocol-compliant object.

By default, the iterator returns 100 values. To return an alternative number of values over the specified interval, provide an N argument.

var it = iterLinspace( 0, 10, 3 );
// returns <Object>

var v = it.next().value;
// returns 0

v = it.next().value;
// returns 5

v = it.next().value;
// returns 10

var bool = it.next().done;
// returns true

Notes

The returned iterator is guaranteed to return the start and stop values. Beware, however, that values between the start and stop are subject to floating-point rounding errors. For example,

var it = iterLinspace( 0.0, 1.0, 3 );
// returns <Object>

var v = it.next().value;
// returns 0

v = it.next().value;
// returns ~0.5

v = it.next().value;
// returns 1.0

where the second iterated value is only guaranteed to be approximately equal to 0.5. If you desire more control over value precision, consider using roundn:

var roundn = require( '@stdlib/math-base-special-roundn' );
var iterMap = require( '@stdlib/iter-map' );

function round( v ) {
    return roundn( v, -2 );
}

// Create an iterator returning values subject to floating-point errors:
var it1 = iterLinspace( 0.0, 1.0, 21 );

// Create an iterator to round each value to the nearest hundredth:
var it2 = iterMap( it1, roundn );

// Perform manual iteration...
var v;
while ( true ) {
    v = it2.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}

If an environment supports Symbol.iterator, the returned iterator is iterable.

Examples

var iterLinspace = require( '@stdlib/iter-linspace' );

// Create a "countdown" iterator:
var it = iterLinspace( 100, 0, 101 );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( v.done ) {
        break;
    }
    console.log( v.value );
}

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.