ipex-llm/docs/readthedocs/source/doc/DLlib/QuickStart/dllib-quickstart.md
dding3 0f20dabda3 add dllib quickstart (#3416)
* add dllib quickstart
* fix init_nncontext issue
2021-11-07 21:21:49 +08:00

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# DLlib Quickstarts
---
![](../../../../image/colab_logo_32px.png)[Run in Google Colab](https://colab.research.google.com/github/intel-analytics/BigDL/blob/branch-2.0/python/dllib/colab-notebook/dllib_keras_api.ipynb)  ![](../../../../image/GitHub-Mark-32px.png)[View source on GitHub](https://github.com/intel-analytics/BigDL/blob/branch-2.0/python/dllib/colab-notebook/dllib_keras_api.ipynb)
---
**In this guide we will demonstrate how to use _DLlib keras style api_ and _DLlib NNClassifier_ for classification.**
### **Step 0: Prepare Environment**
We recommend using [conda](https://docs.conda.io/projects/conda/en/latest/user-guide/install/) to prepare the environment. Please refer to the [install guide](../Overview/chronos.html#install) for more details.
```bash
conda create -n my_env python=3.7 # "my_env" is conda environment name, you can use any name you like.
conda activate my_env
pip install bigdl-dllib
```
### Step 1: Data loading and processing using Spark DataFrame
```python
df = spark.read.csv(path, sep=',', inferSchema=True).toDF("num_times_pregrant", "plasma_glucose", "blood_pressure", "skin_fold_thickness", "2-hour_insulin", "body_mass_index", "diabetes_pedigree_function", "age", "class")
```
We process the data using Spark API and split the data into train and test set.
```python
vecAssembler = VectorAssembler(outputCol="features")
vecAssembler.setInputCols(["num_times_pregrant", "plasma_glucose", "blood_pressure", "skin_fold_thickness", "2-hour_insulin", "body_mass_index", "diabetes_pedigree_function", "age"])
train_df = vecAssembler.transform(df)
changedTypedf = train_df.withColumn("label", train_df["class"].cast(DoubleType())+lit(1))\
.select("features", "label")
(trainingDF, validationDF) = changedTypedf.randomSplit([0.9, 0.1])
```
### Step 3: Define classification model using DLlib keras style api
```python
x1 = Input(shape=(8,))
dense1 = Dense(12, activation='relu')(x1)
dense2 = Dense(8, activation='relu')(dense1)
dense3 = Dense(2)(dense2)
model = Model(x1, dense3)
```
### Step 4: Create NNClassifier and Fit NNClassifier
```python
classifier = NNClassifier(model, CrossEntropyCriterion(), [8]) \
.setOptimMethod(Adam()) \
.setBatchSize(32) \
.setMaxEpoch(150)
nnModel = classifier.fit(trainingDF)
```
### Step 5: Evaluate the trained model
```python
predictionDF = nnModel.transform(validationDF).cache()
predictionDF.sample(False, 0.1).show()
evaluator = MulticlassClassificationEvaluator(
labelCol="label", predictionCol="prediction", metricName="accuracy")
accuracy = evaluator.evaluate(predictionDF)
```