We only use the accuracy for classification problems while for regression problems we do the following:

1. Mean Squared Error: mean_squared_error, MSE or mse
2. Mean Absolute Error: mean_absolute_error, MAE, mae
3. Mean Absolute Percentage Error: mean_absolute_percentage_error, MAPE, mape
4. Cosine Proximity: cosine_proximity, cosine

You can have your custom metrics as well.