incrsummary

Compute a statistical summary incrementally.

Usage

var incrsummary = require( '@stdlib/stats/incr/summary' );

incrsummary()

Returns an accumulator function which incrementally computes a statistical summary.

var accumulator = incrsummary();

accumulator( [x] )

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

var accumulator = incrsummary();

var summary = accumulator();
// returns {}

summary = accumulator( 2.0 );
/* returns
    {
        'count': 1,
        'max': 2.0,
        'min': 2.0,
        'range': 0.0,
        'midrange': 2.0,
        'sum': 2.0,
        'mean': 2.0,
        'variance': 0.0,
        'stdev': 0.0,
        'skewness': null,
        'kurtosis': null
    }
*/

summary = accumulator( 1.0 );
/* returns
    {
        'count': 2,
        'max': 2.0,
        'min': 1.0,
        'range': 1.0,
        'midrange': 1.5,
        'sum': 3.0,
        'mean': 1.5,
        'variance': 0.5,
        'stdev': 0.7071067811865476,
        'skewness': null,
        'kurtosis': null
    }
*/

summary = accumulator( -3.0 );
/* returns
    {
        'count': 3,
        'max': 2.0,
        'min': -3.0,
        'range': 5.0,
        'midrange': -0.5,
        'sum': 0.0,
        'mean': 0.0,
        'variance': 7,
        'stdev': ~2.65,
        'skewness': ~-1.46,
        'kurtosis': null
    }
*/

summary = accumulator();
/* returns
    {
        'count': 3,
        'max': 2.0,
        'min': -3.0,
        'range': 5.0,
        'midrange': -0.5,
        'sum': 0.0,
        'mean': 0.0,
        'variance': 7,
        'stdev': ~2.65,
        'skewness': ~-1.46,
        'kurtosis': null
    }
*/

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 incrsummary = require( '@stdlib/stats/incr/summary' );

var accumulator;
var v;
var i;

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

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