stepNum = sqrt((p3(1)-p1(1))^2+(p3(2)-p1(2))^2+(p3(3)-p1(3))^2)/step;什么意思？

这段代码是用来计算从点p1到点p3的步数的。其中，step是步长。首先，代码中计算了从p1到p3的直线距离，即sqrt((p3(1)-p1(1))^2 + (p3(2)-p1(2))^2 + (p3(3)-p1(3))^2)。然后，将这个距离除以步长step，得到的结果就是从p1到p3所需要的步数stepNum。

相关问题

stepNum = sqrt((p3(1)-p1(1))^2+(p3(2)-p1(2))^2+(p3(3)-p1(3))^2)/step;

This line of code calculates the number of steps needed to move from point p1 to point p3 with a certain step size.

Here's a breakdown of the code:

- `sqrt()` is a function that calculates the square root of a given value.
- `(p3(1)-p1(1))^2` calculates the difference of the x-coordinates of p3 and p1, and then raises it to the power of 2.
- `(p3(2)-p1(2))^2` calculates the difference of the y-coordinates of p3 and p1, and then raises it to the power of 2.
- `(p3(3)-p1(3))^2` calculates the difference of the z-coordinates of p3 and p1, and then raises it to the power of 2.
- These three calculations are multiplied together to get the total distance between p1 and p3.
- This distance value is then divided by the step size to get the number of steps needed to reach p3 from p1.

So in summary, this line of code calculates the number of steps needed to move from p1 to p3 with a certain step size.

p3 = sum((y-p1).^3)/(fre_line_num*sqrt(p2^3));

这是一段MATLAB代码，其中使用了变量y, p1, p2, fre_line_num。它计算出了一个名为p3的值，表达式为：

p3 = sum((y-p1).^3)/(fre_line_num*sqrt(p2^3));

具体来说，它的计算过程为：首先，用y-p1计算出每个数据点与拟合直线的残差，然后取各个残差的立方，并相加求和；接着，将这个和除以fre_line_num和p2的立方根的乘积。其中，fre_line_num是自由度（数据点数目减去拟合曲线的参数数目），p2是标准差估计值。最终，得到的p3值反映了拟合直线的波动程度以及数据的分布情况，通常用于判断拟合的好坏或进行模型选择。