问题描述
我有一个二维欧几里德空间.给出了三点.
I have a two dimensional euclidean space. Three points are given.
例如(p2是中间点):
For example (p2 is the middle point):
Point2D p1 = new Point2D.Double(177, 289);
Point2D p2 = new Point2D.Double(178, 290);
Point2D p3 = new Point2D.Double(178, 291);
现在,我想针对这三点计算曲率.
Now i want to calculate the curvature for these three points.
double curvature = calculateCurvature(p1, p2, p3);
如何执行此操作?是否存在现有方法(没有Java外部库)?
How to do this?Ist there a existing method (no java external libraries)?
- 曲率: https://en.wikipedia.org/wiki/Curvature
- Menger曲率: https://en.wikipedia.org/wiki/Menger_curvature
- Curvature: https://en.wikipedia.org/wiki/Curvature
- Menger Curvature:https://en.wikipedia.org/wiki/Menger_curvature
推荐答案
对于Menger曲率,公式是正确的:
For the Menger Curvature, the formula is right there in the Wikipedia article :
curvature = 4*triangleArea/(sideLength1*sideLength2*sideLength3)
您完全尝试了哪个代码?
Which code did you try exactly?
鉴于您的3分,计算这4个值应该并不难.
It shouldn't be too hard to calculate those 4 values given your 3 points.
此处是一些有用的方法:
/**
* Returns twice the signed area of the triangle a-b-c.
* @param a first point
* @param b second point
* @param c third point
* @return twice the signed area of the triangle a-b-c
*/
public static double area2(Point2D a, Point2D b, Point2D c) {
return (b.x-a.x)*(c.y-a.y) - (b.y-a.y)*(c.x-a.x);
}
/**
* Returns the Euclidean distance between this point and that point.
* @param that the other point
* @return the Euclidean distance between this point and that point
*/
public double distanceTo(Point2D that) {
double dx = this.x - that.x;
double dy = this.y - that.y;
return Math.sqrt(dx*dx + dy*dy);
}
没有更多的事情要做.警告:area2
会根据点的方向(顺时针或逆时针)返回带符号的双精度符号.
There's not much more to do. Warning : area2
returns a signed double, depending on the orientation of your points (clockwise or anticlockwise).
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