All files main.js

100% Statements 101/101
100% Branches 15/15
100% Functions 1/1
100% Lines 101/101

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 1022x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 2x 7012x 7012x 7012x 7012x 7012x 7012x 7012x 7006x 7012x 8x 8x 7012x 5002x 4001x 4001x 1001x 1001x 7012x 1000x 1000x 1002x 7012x 2x 2x 2x 2x 2x  
/**
* @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 exp = require( '@stdlib/math/base/special/exp' );
var phi2 = require( './phi2.js' );
 
 
// MAIN //
 
/**
* Evaluates the moment-generating function (MGF) for a triangular distribution with lower limit `a`, upper limit `b`, and mode `c` at a value `t`.
*
* @param {number} t - input value
* @param {number} a - lower limit
* @param {number} b - upper limit
* @param {number} c - mode
* @returns {number} evaluated MGF
*
* @example
* var y = mgf( 0.5, -1.0, 1.0, 0.0 );
* // returns ~1.021
*
* @example
* var y = mgf( 0.5, -1.0, 1.0, 0.5 );
* // returns ~1.111
*
* @example
* var y = mgf( -0.3, -20.0, 0.0, -2.0 );
* // returns ~24.334
*
* @example
* var y = mgf( -2.0, -1.0, 1.0, 0.0 );
* // returns ~1.381
*
* @example
* var y = mgf( NaN, 0.0, 1.0, 0.5 );
* // returns NaN
*
* @example
* var y = mgf( 0.0, NaN, 1.0, 0.5 );
* // returns NaN
*
* @example
* var y = mgf( 0.0, 0.0, NaN, 0.5 );
* // returns NaN
*
* @example
* var y = mgf( 0.5, 1.0, 0.0, NaN );
* // returns NaN
*
* @example
* var y = mgf( 0.5, 1.0, 0.0, 1.5 );
* // returns NaN
*/
function mgf( t, a, b, c ) {
	if (
		isnan( t ) ||
		isnan( a ) ||
		isnan( b ) ||
		isnan( c ) ||
		a > c ||
		c > b
	) {
		return NaN;
	}
	if ( a < c ) {
		if ( c < b ) {
			return exp( c*t ) * ( ( (c-a)*phi2( (a-c)*t ) ) + ( (b-c)*phi2( (b-c)*t ) ) ) / ( b-a ); // eslint-disable-line max-len
		}
		return exp( c*t ) * phi2( ( a-c ) * t );
	}
	if ( c < b ) {
		return exp( c*t ) * phi2( ( b-c ) * t );
	}
	return exp( c*t );
}
 
 
// EXPORTS //
 
module.exports = mgf;