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 isnan = require( '@stdlib/assert/is-nan' );
  var pow = require( '@stdlib/math/base/special/pow' );
  var SQRT_TWO_PI = require( '@stdlib/constants/float64/sqrt-two-pi' );
  var exp = require( '@stdlib/math/base/special/exp' );
  
  
  // VARIABLES //
  
  var INV_SQRT_TWO_PI = 1.0 / SQRT_TWO_PI;
  
  
  // MAIN //
  
  /**
  * Computes the Gaussian kernel for a value.
  *
  * @private
  * @param {number} u - input value
  * @returns {number} the value for the Gaussian kernel at u
  *
  * @example
  * var u = 5.0;
  * var out = gaussian( u );
  * // returns ~0.0
  */
  function gaussian( u ) {
  	if ( isnan( u ) ) {
  		return NaN;
  	}
  	return INV_SQRT_TWO_PI * exp( -0.5 * pow( u, 2.0 ) );
  }
  
  
  // EXPORTS //
  
  module.exports = gaussian;
  