text: /**
  * @license Apache-2.0
  *
  * Copyright (c) 2018 The Stdlib Authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *    http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
  
  'use strict';
  
  // MODULES //
  
  var isPositiveInteger = require( '@stdlib/assert/is-positive-integer' ).isPrimitive;
  var isNumber = require( '@stdlib/assert/is-number' ).isPrimitive;
  var incrmpcorr = require( '@stdlib/stats/incr/mpcorr' );
  
  
  // MAIN //
  
  /**
  * Returns an accumulator function which incrementally computes a moving squared sample Pearson product-moment correlation coefficient.
  *
  * @param {PositiveInteger} W - window size
  * @param {number} [meanx] - mean value
  * @param {number} [meany] - mean value
  * @throws {TypeError} first argument must be a positive integer
  * @throws {TypeError} second argument must be a number primitive
  * @throws {TypeError} third argument must be a number primitive
  * @returns {Function} accumulator function
  *
  * @example
  * var accumulator = incrmpcorr2( 3 );
  *
  * var r2 = accumulator();
  * // returns null
  *
  * r2 = accumulator( 2.0, 1.0 );
  * // returns 0.0
  *
  * r2 = accumulator( -5.0, 3.14 );
  * // returns ~1.0
  *
  * r2 = accumulator( 3.0, -1.0 );
  * // returns ~0.86
  *
  * r2 = accumulator( 5.0, -9.5 );
  * // returns ~0.74
  *
  * r2 = accumulator();
  * // returns ~0.74
  *
  * @example
  * var accumulator = incrmpcorr2( 3, -2.0, 10.0 );
  */
  function incrmpcorr2( W, meanx, meany ) {
  	var acc;
  	if ( !isPositiveInteger( W ) ) {
  		throw new TypeError( 'invalid argument. First argument must be a positive integer. Value: `' + W + '`.' );
  	}
  	if ( arguments.length > 1 ) {
  		if ( !isNumber( meanx ) ) {
  			throw new TypeError( 'invalid argument. Second argument must be a number primitive. Value: `' + meanx + '`.' );
  		}
  		if ( !isNumber( meany ) ) {
  			throw new TypeError( 'invalid argument. Third argument must be a number primitive. Value: `' + meany + '`.' );
  		}
  		acc = incrmpcorr( W, meanx, meany );
  	} else {
  		acc = incrmpcorr( W );
  	}
  	return accumulator;
  
  	/**
  	* If provided a value, the accumulator function returns an updated accumulated value. If not provided a value, the accumulator function returns the current accumulated value.
  	*
  	* @private
  	* @param {number} [x] - input value
  	* @param {number} [y] - input value
  	* @returns {(number|null)} squared sample correlation coefficient or null
  	*/
  	function accumulator( x, y ) {
  		var r;
  		if ( arguments.length === 0 ) {
  			r = acc();
  			if ( r === null ) {
  				return r;
  			}
  			return r * r;
  		}
  		r = acc( x, y );
  		return r * r;
  	}
  }
  
  
  // EXPORTS //
  
  module.exports = incrmpcorr2;
  