/**
 * @license
 * Copyright 2018 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 { CustomCallback } from '@tensorflow/tfjs';
export declare const progressBarHelper: {
    ProgressBar: any;
    log: Function;
};
/**
 * Terminal-based progress bar callback for tf.Model.fit().
 */
export declare class ProgbarLogger extends CustomCallback {
    private numTrainBatchesPerEpoch;
    private progressBar;
    private currentEpochBegin;
    private epochDurationMillis;
    private usPerStep;
    private batchesInLatestEpoch;
    private terminalWidth;
    private readonly RENDER_THROTTLE_MS;
    /**
     * Construtor of LoggingCallback.
     */
    constructor();
    private formatLogsAsMetricsContent;
    private isFieldRelevant;
}
/**
 * Get a succint string representation of a number.
 *
 * Uses decimal notation if the number isn't too small.
 * Otherwise, use engineering notation.
 *
 * @param x Input number.
 * @return Succinct string representing `x`.
 */
export declare function getSuccinctNumberDisplay(x: number): string;
/**
 * Determine the number of decimal places to display.
 *
 * @param x Number to display.
 * @return Number of decimal places to display for `x`.
 */
export declare function getDisplayDecimalPlaces(x: number): number;
export interface TensorBoardCallbackArgs {
    /**
     * The frequency at which loss and metric values are written to logs.
     *
     * Currently supported options are:
     *
     * - 'batch': Write logs at the end of every batch of training, in addition
     *   to the end of every epoch of training.
     * - 'epoch': Write logs at the end of every epoch of training.
     *
     * Note that writing logs too often slows down the training.
     *
     * Default: 'epoch'.
     */
    updateFreq?: 'batch' | 'epoch';
}
/**
 * Callback for logging to TensorBoard during training.
 *
 * Users are expected to access this class through the `tensorBoardCallback()`
 * factory method instead.
 */
export declare class TensorBoardCallback extends CustomCallback {
    readonly logdir: string;
    private trainWriter;
    private valWriter;
    private batchesSeen;
    private readonly args;
    constructor(logdir?: string, args?: TensorBoardCallbackArgs);
    private logMetrics;
    private ensureTrainWriterCreated;
    private ensureValWriterCreated;
}
/**
 * Callback for logging to TensorBoard during training.
 *
 * Writes the loss and metric values (if any) to the specified log directory
 * (`logdir`) which can be ingested and visualized by TensorBoard.
 * This callback is usually passed as a callback to `tf.Model.fit()` or
 * `tf.Model.fitDataset()` calls during model training. The frequency at which
 * the values are logged can be controlled with the `updateFreq` field of the
 * configuration object (2nd argument).
 *
 * Usage example:
 * ```js
 * // Constructor a toy multilayer-perceptron regressor for demo purpose.
 * const model = tf.sequential();
 * model.add(
 *     tf.layers.dense({units: 100, activation: 'relu', inputShape: [200]}));
 * model.add(tf.layers.dense({units: 1}));
 * model.compile({
 *   loss: 'meanSquaredError',
 *   optimizer: 'sgd',
 *   metrics: ['MAE']
 * });
 *
 * // Generate some random fake data for demo purpose.
 * const xs = tf.randomUniform([10000, 200]);
 * const ys = tf.randomUniform([10000, 1]);
 * const valXs = tf.randomUniform([1000, 200]);
 * const valYs = tf.randomUniform([1000, 1]);
 *
 * // Start model training process.
 * await model.fit(xs, ys, {
 *   epochs: 100,
 *   validationData: [valXs, valYs],
 *    // Add the tensorBoard callback here.
 *   callbacks: tf.node.tensorBoard('/tmp/fit_logs_1')
 * });
 * ```
 *
 * Then you can use the following commands to point tensorboard
 * to the logdir:
 *
 * ```sh
 * pip install tensorboard  # Unless you've already installed it.
 * tensorboard --logdir /tmp/fit_logs_1
 * ```
 *
 * @param logdir Directory to which the logs will be written.
 * @param args Optional configuration arguments.
 * @returns An instance of `TensorBoardCallback`, which is a subclass of
 *   `tf.CustomCallback`.
 *
 * @doc {heading: 'TensorBoard', namespace: 'node'}
 */
export declare function tensorBoard(logdir?: string, args?: TensorBoardCallbackArgs): TensorBoardCallback;