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/math/base/assert/is-nan' );
  var pow = require( '@stdlib/math/base/special/pow' );
  
  
  // MAIN //
  
  /**
  * Evaluates the moment-generating function (MGF) for a gamma distribution.
  *
  * @param {number} t - input value
  * @param {NonNegativeNumber} alpha - shape parameter
  * @param {PositiveNumber} beta - rate parameter
  * @returns {number} evaluated MGF
  *
  * @example
  * var y = mgf( 0.5, 0.5, 1.0 );
  * // returns ~1.414
  *
  * @example
  * var y = mgf( 0.1, 1.0, 1.0 );
  * // returns ~1.111
  *
  * @example
  * var y = mgf( -1.0, 4.0, 2.0 );
  * // returns ~0.198
  *
  * @example
  * var y = mgf( NaN, 1.0, 1.0 );
  * // returns NaN
  *
  * @example
  * var y = mgf( 0.0, NaN, 1.0 );
  * // returns NaN
  *
  * @example
  * var y = mgf( 0.0, 1.0, NaN );
  * // returns NaN
  *
  * @example
  * var y = mgf( 2.0, 4.0, 1.0 );
  * // returns NaN
  *
  * @example
  * var y = mgf( 2.0, -0.5, 1.0 );
  * // returns NaN
  *
  * @example
  * var y = mgf( 2.0, 1.0, 0.0 );
  * // returns NaN
  *
  * @example
  * var y = mgf( 2.0, 1.0, -1.0 );
  * // returns NaN
  */
  function mgf( t, alpha, beta ) {
  	var base;
  	if (
  		isnan( t ) ||
  		isnan( alpha ) ||
  		isnan( beta ) ||
  		alpha < 0.0 ||
  		beta <= 0.0 ||
  		t >= beta
  	) {
  		return NaN;
  	}
  	base = 1.0 - (t / beta);
  	return pow( base, -alpha );
  }
  
  
  // EXPORTS //
  
  module.exports = mgf;
  