using System;
using System.Collections.Generic;
using System.Text;

namespace RungeKutta.ODEs
{
    /// <summary>
    ///  Damped spring with equation in form y'' = a - b y' - c y
    /// </summary>
    class DampedSpring : ODE
    {
        /// <summary>
        /// Constant force 
        /// </summary>
        public float A { get; set; }

        /// <summary>
        /// Drag coefficient
        /// </summary>
        public float B { get; set; }

        /// <summary>
        /// Spring coefficient
        /// </summary>
        public float C { get; set; }
        
        public float EvaluateForceAtState(State state)
        {
            return A - state.velocity * B - state.position * C;
        }
    }
}