message: boosted_trees: fix the comments about gain by removing a confusing dash.
diff: @@ -137,7 +137,7 @@ struct NodeStats {
  Eigen::MatrixXf hessian =
  TensorToEigenMatrix(grad_stats.second.t, grad_dim, grad_dim);
  // I is an identity matrix.
  - // The gain in general form is -g^T (H+l2 I)^-1 g.
  + // The gain in general form is g^T (H+l2 I)^-1 g.
  // The node weights are -(H+l2 I)^-1 g.
  Eigen::MatrixXf identity;
  identity.setIdentity(grad_dim, grad_dim);
  @@ -240,7 +240,7 @@ struct NodeStats {
  // given regularized Hessian and gradient vector g.
  void CalculateWeightAndGain(const Eigen::MatrixXf& hessian_and_reg,
  const Eigen::VectorXf& g) {
  - // The gain in general form is -g^T (Hessian_and_regularization)^-1 g.
  + // The gain in general form is g^T (Hessian_and_regularization)^-1 g.
  // The node weights are -(Hessian_and_regularization)^-1 g.
  Eigen::VectorXf weight;
  // If we want to calculate x = K^-1 v, instead of explicitly calculating
  