All files main.js

100% Statements 88/88
100% Branches 11/11
100% Functions 1/1
100% Lines 88/88

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 891x 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 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 2017x 2017x 2017x 2017x 5x 5x 2012x 2017x 256x 256x 2017x 1510x 1510x 246x 2017x 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.
*/
 
'use strict';
 
// MODULES //
 
var isnan = require( '@stdlib/math/base/assert/is-nan' );
 
 
// MAIN //
 
/**
* Computes the modified huber loss gradient with respect to prediction.
*
* ## Notes
*
* -   If `y` is not +1 or -1, the function returns `NaN`.
*
* ## References
*
* -   Zhang, Tong. 2004. "Solving Large Scale Linear Prediction Problems Using Stochastic Gradient Descent Algorithms." In _Proceedings of the Twenty-First International Conference on Machine Learning_, 116. New York, NY, USA: Association for Computing Machinery. doi:[10.1145/1015330.1015332][@zhang:2004a].
*
* [@zhang:2004a]: https://doi.org/10.1145/1015330.1015332
*
* @param {number} y - true target value
* @param {number} p - predicted value
* @returns {number} modified huber loss gradient
*
* @example
* var v = modifiedHuberGradient( 1.0, 0.782 );
* // returns ~-0.436
*
* @example
* var v = modifiedHuberGradient( 1.0, 0.202 );
* // returns -1.596
*
* @example
* var v = modifiedHuberGradient( 1.0, -0.999 );
* // returns -3.998
*
* @example
* var v = modifiedHuberGradient( -1.0, 0.234 );
* // returns 2.468
*
* @example
* var v = modifiedHuberGradient( -1.0, 0.2 );
* // returns 2.4
*
* @example
* var v = modifiedHuberGradient( 1.0, -0.9 );
* // returns -3.8
*/
function modifiedHuberGradient( y, p ) {
	var z;
 
	if ( isnan( y ) || isnan( p ) || ( y !== -1.0 && y !== 1.0 ) ) {
		return NaN;
	}
	z = y*p;
	if ( z >= 1.0 ) {
		return 0.0;
	}
	if ( z >= -1.0 ) {
		return -2.0 * ( 1.0 - z ) * y;
	}
	return -4.0*y;
}
 
 
// EXPORTS //
 
module.exports = modifiedHuberGradient;