97c3a80a34
- Group C API. - Add C API sphinx doc. - Consistent use of `OptionalArg` and the parameter name `config`. - Remove call to deprecated functions in demo. - Fix some formatting errors. - Add links to c examples in the document (only visible with doxygen pages) - Fix arrow.
Defining a Custom Data Iterator to Load Data from External Memory
A simple demo for using custom data iterator with XGBoost. The feature is still experimental and not ready for production use. If you are not familiar with C API, please read its introduction in our tutorials and visit the basic demo first.
Defining Data Iterator
In the example, we define a custom data iterator with 2 methods: reset and next. The
next method passes data into XGBoost and tells XGBoost whether the iterator has reached
its end, and the reset method resets iterations. One important detail when using the C
API for data iterator is users need to make sure that the data passed into next method
must be kept in memory until the next iteration or reset is called. The external memory
DMatrix is not limited to training, but also valid for other features like prediction.