ROC Curve Module

The roc class derives from plotting and provides ROC (Receiver Operating Characteristic) curve computation and storage for multi-class classifiers. It is used by the built-in AccuracyMetric to generate AUC tables after training.

Struct: `roc_t`

Header: <plotting/roc.h>

Field	Type	Description
`cls`	`int`	Class index (0-based) that this ROC curve belongs to.
`kfold`	`int`	k-fold index for which the ROC was computed.
`model`	`std::string`	Name of the model that produced these scores.
`_auc`	`std::vector<double>`	Area under the ROC curve for each threshold (one per class).
`tpr_`	`std::vector<std::vector<double>>`	True-positive rates across thresholds (outer: threshold, inner: class).
`fpr_`	`std::vector<std::vector<double>>`	False-positive rates across thresholds.
`truth`	`std::vector<std::vector<int>>*`	Pointer to truth labels (shape `[N_events, N_classes]`).
`scores`	`std::vector<std::vector<double>>*`	Pointer to model score tensors (shape `[N_events, N_classes]`).

Class: `roc`

Header: <plotting/roc.h>

Inheritance: plotting

Public Methods

Signature	Description
`void build_ROC(std::string name, int kfold, std::vector<int>* label, std::vector<std::vector<double>>* scores)`	Computes the ROC curves for classifier name, fold kfold, given ground-truth label (flat integer class vector) and scores (one row per event, one column per class). Results are stored in the internal `roc_data` and `labels` maps.
`std::vector<roc_t*> get_ROC()`	Returns pointers to all computed `roc_t` objects. The caller does not own the returned pointers (owned by `roc`).

Public Fields

Field / Type	Description
`std::map<std::string, std::map<int, std::vector<std::vector<double>>*>> roc_data`	Maps model-name → {kfold → score vectors}.
`std::map<std::string, std::map<int, std::vector<std::vector<int>>*>> labels`	Maps model-name → {kfold → truth label vectors}.

Example:

roc roc_obj;
roc_obj.build_ROC("MyModel", 0, &truth_labels, &model_scores);
for (roc_t* r : roc_obj.get_ROC()) {
    std::cout << "AUC (class 0): " << r->_auc[0] << std::endl;
}