incrnansum

Compute a sum incrementally, ignoring NaN values.

The sum is defined as

Usage

var incrnansum = require( '@stdlib/stats/incr/nansum' );

incrnansum()

Returns an accumulator function which incrementally computes a sum, ignoring NaN values.

var accumulator = incrnansum();

accumulator( [x] )

If provided an input value x, the accumulator function returns an updated sum. If not provided an input value x, the accumulator function returns the current sum.

var accumulator = incrnansum();

var sum = accumulator( 2.0 );
// returns 2.0

sum = accumulator( 1.0 );
// returns 3.0

sum = accumulator( NaN );
// returns 3.0

sum = accumulator( 3.0 );
// returns 6.0

sum = accumulator();
// returns 6.0

Notes

Input values are not type checked. If non-numeric inputs are possible, you are advised to type check and handle accordingly before passing the value to the accumulator function.
For long running accumulations or accumulations of large numbers, care should be taken to prevent overflow.

Examples

var randu = require( '@stdlib/random/base/randu' );
var incrnansum = require( '@stdlib/stats/incr/nansum' );

var accumulator;
var v;
var i;

// Initialize an accumulator:
accumulator = incrnansum();

// For each simulated datum, update the sum...
for ( i = 0; i < 100; i++ ) {
    if ( randu() < 0.2 ) {
        v = NaN;
    } else {
        v = randu() * 100.0;
    }
    accumulator( v );
}
console.log( accumulator() );