@tensorflow/tfjs-core
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Hardware-accelerated JavaScript library for machine intelligence
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JavaScript
/**
* @license
* Copyright 2020 Google LLC. All Rights Reserved.
* 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.
* =============================================================================
*/
import { convertToTensor } from '../../tensor_util_env';
import { assertShapesMatch } from '../../util';
import { add } from '../add';
import { log } from '../log';
import { Reduction } from '../loss_ops_utils';
import { mul } from '../mul';
import { neg } from '../neg';
import { op } from '../operation';
import { scalar } from '../scalar';
import { sub } from '../sub';
import { computeWeightedLoss } from './compute_weighted_loss';
/**
* Computes the log loss between two tensors.
*
* @param labels The ground truth output tensor, same dimensions as
* 'predictions'.
* @param predictions The predicted outputs.
* @param weights Tensor whose rank is either 0, or the same rank as
* `labels`, and must be broadcastable to `labels` (i.e., all dimensions
* must be either `1`, or the same as the corresponding `losses`
* dimension).
* @param epsilon A small increment to avoid taking log of zero
* @param reduction Type of reduction to apply to loss. Should be of type
* `Reduction`
*
* @doc {heading: 'Training', subheading: 'Losses', namespace: 'losses'}
*/
function logLoss_(labels, predictions, weights, epsilon = 1e-7, reduction = Reduction.SUM_BY_NONZERO_WEIGHTS) {
const $labels = convertToTensor(labels, 'labels', 'logLoss');
const $predictions = convertToTensor(predictions, 'predictions', 'logLoss');
let $weights = null;
if (weights != null) {
$weights = convertToTensor(weights, 'weights', 'logLoss');
}
assertShapesMatch($labels.shape, $predictions.shape, 'Error in logLoss: ');
const one = scalar(1);
const epsilonScalar = scalar(epsilon);
const l1 = neg(mul($labels, log(add($predictions, epsilonScalar))));
const l2 = mul(sub(one, $labels), log(add(sub(one, $predictions), epsilonScalar)));
const losses = sub(l1, l2);
return computeWeightedLoss(losses, $weights, reduction);
}
export const logLoss = op({ logLoss_ });
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