Euler工程，相邻元素乘积最大。 给了一个20x20的两位数矩阵，其中的红字部分的积为： 26x63x78x14=1788696 那么，任意方向上（上、下、左、右、对角）4个相邻的数的最大乘积是多少？-In the 20x20 grid below, four numbers along a diagonal line have been marked in red. 08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 7

龙格库塔78阶积分器，matlab语言。可设置积分参数。缺点是中间过程在积分区间较大是无法显示。-78-order Runge-Kutta integrator, the Matlab language. You can set the integration parameters. The disadvantage is that the intermediate process in the larger integration interval can not be displayed.

考虑地球J2项摄动的轨道积分器，变步长，基于龙格库塔78阶，(orbital integrator considering the J2 pertubation, based on the Runge-Kutta 78 integrator, use automatic step control)