iterTriangleWave

Create an iterator which generates a triangle wave.

A triangle waveform is represented by the following equation

f left-parenthesis t semicolon tau comma a comma phi right-parenthesis equals StartFraction 2 a Over pi EndFraction arc sine sine StartFraction 2 pi left-parenthesis t minus phi right-parenthesis Over tau EndFraction

where τ is the period, a is the peak amplitude, and φ is the phase offset.

Usage

var iterTriangleWave = require( '@stdlib/simulate/iter/triangle-wave' );

iterTriangleWave( [options] )

Returns an iterator which generates a triangle wave.

var it = iterTriangleWave();
// returns <Object>

var v = it.next().value;
// returns <number>

v = it.next().value;
// returns <number>

v = it.next().value;
// returns <number>

// ...

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.

The function supports the following options:

  • period: period (i.e., the number of iterations before a waveform repeats). Default: 10.
  • amplitude: peak amplitude. Default: 1.0.
  • offset: phase offset (in units of iterations; zero-based). A negative offset translates a waveform to the left. A positive offset translates a waveform to the right. Default: 0.
  • iter: number of iterations. Default: 1e308.

By default, the function returns an iterator which generates a triangle wave that repeats every 10 iterations. To specify an alternative period, set the period option.

var opts = {
    'period': 4
};

var it = iterTriangleWave( opts );
// returns <Object>

var v = it.next().value;
// returns 0.0

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

v = it.next().value;
// returns 0.0

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

v = it.next().value;
// returns 0.0

// ...

To adjust at what point the iterator begins in the waveform cycle, set the phase offset option. For example, to translate the waveform to the left,

var opts = {
    'period': 4,
    'offset': -1
};

var it = iterTriangleWave( opts );
// returns <Object>

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

v = it.next().value;
// returns 0.0

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

v = it.next().value;
// returns 0.0

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

// ...

To translate the waveform to the right,

var opts = {
    'period': 4,
    'offset': 1
};

var it = iterTriangleWave( opts );
// returns <Object>

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

v = it.next().value;
// returns 0.0

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

v = it.next().value;
// returns 0.0

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

// ...

By default, the function returns an infinite iterator (i.e., an iterator which never ends). To limit the number of iterations, set the iter option.

var opts = {
    'iter': 2
};
var it = iterTriangleWave( opts );
// returns <Object>

var v = it.next().value;
// returns <number>

v = it.next().value;
// returns <number>

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

Notes

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

Examples

var iterTriangleWave = require( '@stdlib/simulate/iter/triangle-wave' );

// Create an iterator:
var opts = {
    'period': 10,
    'amplitude': 10.0,
    'offset': -5,
    'iter': 100
};
var it = iterTriangleWave( opts );

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