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Load MXNet model

In this tutorial, you learn how to load an existing MXNet model and use it to run a prediction task.


This tutorial requires the installation of Java Kernel. For more information on installing the Java Kernel, see the README.

// %mavenRepo snapshots

%maven ai.djl:api:0.22.1
%maven ai.djl:model-zoo:0.22.1
%maven ai.djl.mxnet:mxnet-engine:0.22.1
%maven ai.djl.mxnet:mxnet-model-zoo:0.22.1
%maven org.slf4j:slf4j-simple:1.7.32
import java.awt.image.*;
import java.nio.file.*;
import ai.djl.*;
import ai.djl.inference.*;
import ai.djl.ndarray.*;
import ai.djl.modality.*;
import ai.djl.translate.*;
import ai.djl.util.*;

Step 1: Prepare your MXNet model

This tutorial assumes that you have a MXNet model trained using Python. A MXNet symbolic model usually contains the following files: * Symbol file: {MODEL_NAME}-symbol.json - a json file that contains network information about the model * Parameters file: {MODEL_NAME}-{EPOCH}.params - a binary file that stores the parameter weight and bias * Synset file: synset.txt - an optional text file that stores classification classes labels

This tutorial uses a pre-trained MXNet resnet18_v1 model.

We use DownloadUtils for downloading files from internet."", "build/resnet/resnet18_v1-symbol.json", new ProgressBar());"", "build/resnet/resnet18_v1-0000.params", new ProgressBar());"", "build/resnet/synset.txt", new ProgressBar());
Downloading: 100% |████████████████████████████████████████| resnet18_v1-symbol.json
Downloading: 100% |████████████████████████████████████████| resnet18_v1-0000.params
Downloading: 100% |████████████████████████████████████████| synset.txt

Step 2: Load your model

Path modelDir = Paths.get("build/resnet");
Model model = Model.newInstance("resnet");
model.load(modelDir, "resnet18_v1");

Step 3: Create a Translator

Pipeline pipeline = new Pipeline();
pipeline.add(new CenterCrop()).add(new Resize(224, 224)).add(new ToTensor());
Translator<Image, Classifications> translator = ImageClassificationTranslator.builder()

Step 4: Load image for classification

var img = ImageFactory.getInstance().fromUrl("");

Step 5: Run inference

Predictor<Image, Classifications> predictor = model.newPredictor(translator);
Classifications classifications = predictor.predict(img);

    {"class": "n02123045 tabby, tabby cat", "probability": 0.48384}
    {"class": "n02123159 tiger cat", "probability": 0.20599}
    {"class": "n02124075 Egyptian cat", "probability": 0.18810}
    {"class": "n02123394 Persian cat", "probability": 0.06411}
    {"class": "n02127052 lynx, catamount", "probability": 0.01021}


Now, you can load any MXNet symbolic model and run inference.

You might also want to check out load_pytorch_model.ipynb which demonstrates loading a local model using the ModelZoo API.