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add detailed comment about gbmcore

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This commit is contained in:
tqchen
2014-02-07 20:30:39 -08:00
parent 779d6a34de
commit 3dd477c4b2
3 changed files with 23 additions and 5 deletions
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21
booster/xgboost_gbmbase.h
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@@ -21,13 +21,28 @@ namespace xgboost{
* \brief a base model class,
* that assembles the ensembles of booster together and provide single routines to do prediction buffer and update
* this class can be used as base code to create booster variants
*
* *
* relation to xgboost.h:
* (1) xgboost.h provides a interface to a single booster(e.g. a single regression tree )
* while GBMBaseModel builds upon IBooster to build a class that
* ensembls the boosters together;
* (2) GBMBaseModel provides prediction buffering scheme to speedup training;
* (3) Summary: GBMBaseModel is a standard wrapper for boosting ensembles;
*
* Usage of this class, the number index gives calling dependencies:
* (1) model.SetParam to set the parameters
* (2) model.LoadModel to load old models or model.InitModel to create a new model
* (3) model.InitTrainer before calling model.Predict and model.DoBoost
* (4) model.Predict to get predictions given a instance
* (4) model.DoBoost to update the ensembles, add new booster to the model
* (4) model.SaveModel to save learned results
*
* Bufferring: each instance comes with a buffer_index in Predict.
* when param.num_pbuffer != 0, a unique buffer index can be
* assigned to each instance to buffer previous results of boosters,
* this helps to speedup training, so consider assign buffer_index
* for each training instances, if buffer_index = -1, the code
* recalculate things from scratch and will still works correctly
*/
class GBMBaseModel{
public:
@@ -214,7 +229,8 @@ namespace xgboost{
// load buffered results if any
if( param.do_reboost == 0 && buffer_index >= 0 ){
utils::Assert( buffer_index < param.num_pbuffer, "buffer index exceed num_pbuffer" );
utils::Assert( buffer_index < param.num_pbuffer,
"buffer index exceed num_pbuffer" );
istart = this->pred_counter[ buffer_index ];
psum = this->pred_buffer [ buffer_index ];
}
@@ -278,4 +294,3 @@ namespace xgboost{
};
};
#endif