Final answer:
To make the .fit() method care about MAPE, use a library like scikit-learn or TensorFlow to create and implement a custom MAPE loss function, then pass it to the model during compilation or as part of model selection utilities.
Step-by-step explanation:
In machine learning, the .fit() method is used to train a model on a dataset. To make the .fit() method care about Mean Absolute Percentage Error (MAPE), you must ensure that the algorithm you are using supports this evaluation metric or you can define a custom loss function that calculates MAPE. Typically, to define MAPE as a metric, you would:
- Choose a machine learning library, such as scikit-learn or TensorFlow, that allows you to customize loss functions.
- Implement the MAPE function according to the library's guidelines. This involves writing a function that takes as inputs the true values and the predicted values from the model, and then calculates the percentage errors.
- Pass your custom MAPE function to the model as the loss function when compiling it (in libraries like TensorFlow) or as a scoring parameter in model selection utilities (as in scikit-learn).
MAPE is particularly useful when you are dealing with regression problems and you want errors to be represented as percentages, which can provide a clearer picture of model performance in certain cases.