namespace CeresSharp.Enums;

/// <summary>
/// Numeric differentiation methods for NumericDiffCostFunction.
/// Values must match ceres_numeric_diff_method_t enum in ceres_wrapper.h.
/// Note: The wrapper defines its own enum order (Forward=0, Central=1) which differs
/// from ceres::NumericDiffMethodType (Central=0, Forward=1). The wrapper uses a switch
/// statement to map correctly, so C# must match the wrapper's enum.
/// </summary>
public enum NumericDiffMethod
{
    /// <summary>
    /// Compute forward finite difference: f'(x) ~ (f(x+h) - f(x)) / h.
    /// </summary>
    Forward = 0,

    /// <summary>
    /// Compute central finite difference: f'(x) ~ (f(x+h) - f(x-h)) / 2h.
    /// </summary>
    Central = 1,

    /// <summary>
    /// Adaptive numerical differentiation using Ridders' method.
    /// </summary>
    Ridders = 2
}