在Java脚本中根据点坐标计算体积
如何从这样的任意点坐标数组在Java脚本中计算体积?
const points = [
[0, 1, 0],
[1, -1, 1],
[-1, -1, 1],
[0, -1, -1]
]
我使用了scipy.spatial.vvexHull库来计算体积,但我不能在我的react js应用程序上使用python,因此我需要一个能够执行类似功能的javascrip库。提前感谢
解决方案
This JavaScript library执行任意维度的Delaunay三角剖分。因此,您可以使用我在Python中向您展示的相同方式。
我在这里使用Node:
var triangulate = require("delaunay-triangulate")
const vertices = [
[0.,0.,0.], [0.,1.,0.1], [1.,1.,0.1], [0.,1.,0.],
[0.,0.,1.], [0.,1.,1.1], [1.,1.,1.1], [0.,1.,1.]
];
const tetrahedra_indices = triangulate(vertices);
var tetrahedra = new Array(tetrahedra_indices.length);
for(let i = 0; i < tetrahedra.length; i++){
const indices = tetrahedra_indices[i];
tetrahedra[i] = [
vertices[indices[0]],
vertices[indices[1]],
vertices[indices[2]],
vertices[indices[3]]
];
}
const array1_minus_array2 = (arr1, arr2) => (
arr2.map(function(num, idx){ return num - arr1[idx] })
);
const det3x3 = arr => (
arr[0][0] * (arr[1][1]*arr[2][2] - arr[1][2]*arr[2][1]) -
arr[0][1] * (arr[1][0]*arr[2][2] - arr[1][2]*arr[2][0]) +
arr[0][2] * (arr[1][0]*arr[2][1] - arr[1][1]*arr[2][0])
);
const volume_tetrahedron = tetrahedron => {
const a = tetrahedron[0];
const b = tetrahedron[1];
const c = tetrahedron[2];
const d = tetrahedron[3];
const matrix3x3 = [
array1_minus_array2(a, d),
array1_minus_array2(b, d),
array1_minus_array2(c, d)
];
return Math.abs(det3x3(matrix3x3)) / 6;
};
const volumes = tetrahedra.map(volume_tetrahedron);
const volume = volumes.reduce( (a,b) => a + b );
console.log(volume);
// 0.5166666666666667
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