itercusumabs

Create an iterator which iteratively computes a cumulative sum of absolute values.

The cumulative sum of absolute values is defined as

StartLayout 1st Row 1st Column s 0 2nd Column equals StartAbsoluteValue x 0 EndAbsoluteValue 2nd Row 1st Column s 1 2nd Column equals StartAbsoluteValue x 1 EndAbsoluteValue plus s 0 3rd Row 1st Column s 2 2nd Column equals StartAbsoluteValue x 2 EndAbsoluteValue plus s 1 4th Row 1st Column s Subscript n 2nd Column equals StartAbsoluteValue x Subscript n Baseline EndAbsoluteValue plus s Subscript n minus 1 Baseline equals StartAbsoluteValue x Subscript n Baseline EndAbsoluteValue plus sigma-summation Underscript i equals 0 Overscript n minus 1 Endscripts StartAbsoluteValue x Subscript i Baseline EndAbsoluteValue EndLayout

Usage

var itercusumabs = require( '@stdlib/stats/iter/cusumabs' );

itercusumabs( iterator )

Returns an iterator which iteratively computes a cumulative sum of absolute values.

var array2iterator = require( '@stdlib/array/to-iterator' );

var arr = array2iterator( [ 2.0, 1.0, 3.0, -7.0, -5.0 ] );
var it = itercusumabs( arr );

var s = it.next().value;
// returns 2.0

s = it.next().value;
// returns 3.0

s = it.next().value;
// returns 6.0

s = it.next().value;
// returns 13.0

s = it.next().value;
// returns 18.0

Notes

  • If an iterated value is non-numeric (including NaN), the function returns NaN for all future iterations. If non-numeric iterated values are possible, you are advised to provide an iterator which type checks and handles non-numeric values accordingly.

Examples

var runif = require( '@stdlib/random/iter/uniform' );
var itercusumabs = require( '@stdlib/stats/iter/cusumabs' );

// Create an iterator for generating uniformly distributed pseudorandom numbers:
var rand = runif( -10.0, 10.0, {
    'seed': 1234,
    'iter': 100
});

// Create an iterator for iteratively computing a cumulative sum of absolute values:
var it = itercusumabs( rand );

// Perform manual iteration...
var v;
while ( true ) {
    v = it.next();
    if ( typeof v.value === 'number' ) {
        console.log( 'sumabs: %d', v.value );
    }
    if ( v.done ) {
        break;
    }
}