This function returns the numerical derivative of an analytic function. Of special note, is the incorporation of the "complex stepderivative"approach which offers greatly improved derivative accuracy compared to approximations. This is especially

四阶龙格库塔算法。deltaT为积分步长，XX为X_k,X_next为X_k+1，Control以及Param为用户可选参数。微分方程在deriv中定义。-RungeKutta,where deltaT refers to the step size, XX refers to X_k, X_next refers to X_k+1, Control and Param is user defined parameters. The differential equation should be

产生高斯脉冲的前15阶导函数。 %该函数的输入参数为： %1)矢量t定义时间轴； %2)高斯脉冲导函数的阶数k，取值范围[1,15]； %3)脉冲形成因子alpha。 %没有输出值。 %函数3将返回一个矢量deriv，这个变量是在时间轴t上计算得到的k阶 %高斯脉冲导函数的若干数值。