# incrmidrange

Compute a mid-range incrementally.

The mid-range, or mid-extreme, is the arithmetic mean of maximum and minimum values. Accordingly, the mid-range is the midpoint of the range and a measure of central tendency.

## Usage

``````var incrmidrange = require( '@stdlib/stats/incr/midrange' );
``````

#### incrmidrange()

Returns an accumulator `function` which incrementally computes a mid-range.

``````var accumulator = incrmidrange();
``````

#### accumulator( [x] )

If provided an input value `x`, the accumulator function returns an updated mid-range. If not provided an input value `x`, the accumulator function returns the current mid-range.

``````var accumulator = incrmidrange();

var midrange = accumulator();
// returns null

midrange = accumulator( -2.0 );
// returns -2.0

midrange = accumulator( 1.0 );
// returns -0.5

midrange = accumulator( 3.0 );
// returns 0.5

midrange = accumulator();
// returns 0.5
``````

## Notes

• Input values are not type checked. If provided `NaN`, the accumulated value is `NaN` for all future invocations. If non-numeric inputs are possible, you are advised to type check and handle accordingly before passing the value to the accumulator function.

## Examples

``````var randu = require( '@stdlib/random/base/randu' );
var incrmidrange = require( '@stdlib/stats/incr/midrange' );

var accumulator;
var v;
var i;

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

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