A tip for using trained models in RapidMiner

There are some cases that you may train a model like Artificial Neural Network, SVD or Linear regression in RapidMiner and you may need to reapply your model to the other testing data in future. There are two options to handle it. The first option is to save the model for future use and reopen it when it is needed and then update the old test data set with the newer data set and run the model. This option is reasonable when the training process does not last so long. In the cases that you are dealing with a huge data set and your model needs couple of hours to get trained, like ANN models, this option seems tedious. The second way to handle this problem is to just save the trained model and then apply it later on the new data set. In this post I will illustrate this process.

At first you need to build the original model. Let’s say that we have an ANN model similar to the following figure.

 To save the trained model, you should use Write Model operator. Search for this operator and add it to the model and connect the mod port of the Neural Net operator to the mod port of the Write Model operator and then connect the thr port to the mod port of the Apply Model as illustrated in the figure below. In your computer create a new Text file. It will be used by RapidMiner to save the model. Afterward, in Write Model operator properties window enter the address of the new created text file in model file textbox.

You can also add the Write Model operator after the Apply Model operator too, like the following figure.

Now, when you are going to test your model on the new test data set, you need to create a new project and then import your saved model to this process by using Read Model operator. Add the Apply Model operator and then import the new data set to the model and connect it to the unl port of the Apply Model operator. Your model should look like the following operator.