All files hyp2f1negcequalbc.js

94.87% Statements 74/78
50% Branches 2/4
100% Functions 1/1
94.87% Lines 74/78

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 791x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x 28x     28x 28x 28x 28x 28x 28x     28x 28x 1x 1x 1x 1x 1x  
/**
* @license Apache-2.0
*
* Copyright (c) 2026 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.
*
*
* ## Notice
*
* The original C code and copyright notice are from the [Cephes Mathematical Library]{@link https://www.netlib.org/cephes/}. The implementation has been modified for JavaScript.
*
* ```text
* (C) Copyright Stephen L. Moshier 1984, 1987, 1992, 2000.
*
* Use, modification and distribution are subject to the
* Cephes Mathematical Library License. (See accompanying file
* LICENSE or copy at https://smath.com/en-US/view/CephesMathLibrary/license)
* ```
*/
 
'use strict';
 
// MODULES //
 
var abs = require( '@stdlib/math/base/special/abs' );
var max = require( '@stdlib/math/base/special/max' );
 
 
// MAIN //
 
/**
* Evaluates 2F1(a, b; b; x) when `b = c` is a negative integer using AMS55 #15.4.2.
*
* @private
* @param {number} a - first parameter
* @param {number} b - second parameter (equals c, a non-positive integer)
* @param {number} x - argument
* @returns {number} function value, or NaN if precision is insufficient
*/
function hyp2f1NegCEqualBC( a, b, x ) {
	var collectorMax;
	var collector;
	var sum;
	var k;
 
	collectorMax = 1.0;
	collector = 1.0;
	sum = 1.0;
 
	if ( abs( b ) >= 1.0e5 ) {
		return NaN;
	}
	for ( k = 1; k <= -b; k++ ) {
		collector *= ( ( a + k - 1.0 ) * x ) / k;
		collectorMax = max( abs( collector ), collectorMax );
		sum += collector;
	}
	if ( 1.0e-16 * ( 1.0 + ( collectorMax / abs( sum ) ) ) > 1.0e-7 ) {
		return NaN;
	}
	return sum;
}
 
 
// EXPORTS //
 
module.exports = hyp2f1NegCEqualBC;