javascript - 'info' 和 'history' 在 tensorflow.js 的模型中未定义

Question

我正在尝试在我的 expo 项目中使用 tensorflow.js 库构建简单的机器学习模型。在代码沙箱中运行相同的代码不会出现任何错误。通过在 visual studio code 中运行，它也会给出未定义信息、历史记录和日志的错误。我的代码附在下面:

import React from 'react';
import {View, Text, StyleSheet} from 'react-native';
import * as tf from '@tensorflow/tfjs';
import '@tensorflow/tfjs-react-native';

export default class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      isTfReady: false,
    };
  }

  init() {
    const model = tf.sequential({
        layers: [
            tf.layers.dense({
                inputShape: [784],
                units: 32,
                activation: "relu"
            }),
            tf.layers.dense({
                units: 10,
                activation: "softmax"
            })
        ]
    });
    model.weights.forEach(w => {
        console.log(w.name, w.shape);
    });
    model.weights.forEach(w => {
        const newVals = tf.randomNormal(w.shape);
        // w.val is an instance of tf.Variable
        w.val.assign(newVals);
    });
    model.compile({
        optimizer: "sgd",
        loss: "categoricalCrossentropy",
        metrics: ["accuracy"]
    });
    const data = tf.randomNormal([100, 784]);
    const labels = tf.randomUniform([100, 10]);

    function onBatchEnd(batch, logs) {
      logs.acc = parseFloat((logs.acc * 100).toFixed(2));
      logs.loss = parseFloat((logs.loss * 100).toFixed(3));

        console.log("Accuracy", logs.acc);
    }

    // Train for 5 epochs with batch size of 32.
    model
        .fit(data, labels, {
            epochs: 5,
            batchSize: 32,
            callbacks: {
                onBatchEnd
            }
        })
        .then(info => {
            console.log("Final accuracy", info.history.acc);
        });
  }

  async componentDidMount() {
    // Wait for tf to be ready.
    await tf.ready();
    // Signal to the app that tensorflow.js can now be used.
    this.setState({
      isTfReady: true,
    });
  }


  render() {
    //this.init()
    // //
    return (


      <View style={styles.buttonContainer}>

            <Text>{'Final accuracy', info.history.acc}</Text>

      </View>
    )
  }
}
const styles = StyleSheet.create({
  // container: {
  //   flex: 1,
  // },
  buttonContainer: {
   // flexDirection: 'row',
    alignItems: 'center',
    marginTop: 50,
  },
})

错误信息是:

Can't find variable info

Answer 1

信息可以添加到应用程序的状态

.then(info => {
        this.state = {...this.state, info}
        console.log("Final accuracy", info.history.acc);
    });

仅在模型使用条件渲染完成训练后显示信息

render() {
    const {info} = this.state; 
    return (


      <View style={styles.buttonContainer}>

            {info && <Text>{'Final accuracy', info.history.acc}</Text>}

      </View>
    )
  }