export interface XGBTreeParams {
    maxDepth: number;
    lambda: number;
    gamma: number;
    minChildWeight: number;
}
export declare class XGBTree {
    private params;
    private root;
    constructor(params: XGBTreeParams);
    /**
     * X, g, h are aligned by row; featureIndices restricts the columns
     * considered (column subsampling is decided by the caller per tree).
     */
    fit(X: number[][], g: number[], h: number[], featureIndices: number[]): void;
    private leafWeight;
    private build;
    predict(X: number[][]): number[];
    featureImportances(nFeatures: number): number[];
    featureCountHint(): number;
}