[英]Java // Array // Multiplication // For-loop;
目标:使用旋转矩阵产生旋转;
private double[][] rotateX = {{1.00,0.00,0.00},{0.00,Math.cos(theta),Math.sin(-theta)},{0.00,Math.sin(theta),Math.cos(theta)}}; // Rotation matrice for x axis;
问题定义:输出与预期不符;
预期产量:
newX = 3
newY = -2.236
newZ = -0.002
// Checked in MathCAD;
产生的输出:
newX = 3.00
newY =-2.00
newZ = 1.0000000000000002
应用的代码:
public class Test2 {
private double[] target = {3.00,1.00,2.00}; // target data for matrix multiplication;
private double[] product = {0.00,0.00,0.00}; // product of the for-loop;
private double theta = Math.toRadians(90.00); // Rotation angle;
private double[][] rotateX = {{1.00,0.00,0.00},
{0.00,Math.cos(theta),Math.sin(-theta)},
{0.00,Math.sin(theta),Math.cos(theta)}}; // Rotation matrice for x axis;
private void rotateAroundX(){
double temp; // temp. data storage;
double newX = 0.00; // new x after for-loop;
double newY = 0.00; // new y after for-loop;
double newZ = 0.00; // new z after for-loop;
for(int i = 0; i < rotateX.length ; i ++){ // check how many items are stored in the matrix;
for(int j = 0; j < rotateX[i].length; j++){ // check how many elements are stored in each item;
temp = rotateX[i][j] * target[j]; // store product of the multiplication in temp;
if(i == 0){
newX += temp; // if i index is 0 finalize matrix multiplication and set newX; Ex. 1 row of rotateX - (1.00*3.00 + 0.00*1.00 + 0.00*2.00);
}
if(i == 1){ // if i index is 1 finalize matrix multiplication and set newY;
newY += temp;
}
if(i == 2){ // if i index is 2 finalize matrix multiplication and set newZ;
newZ += temp;
}
}
}
this.product[0] = newX; // Add newX to product;
this.product[1] = newY; // Add newY to product;
this.product[2] = newZ; // Add newZ to product;
}
public void sart(){
rotateAroundX(); // run test-case;
for (double e : product){
System.out.println(e); // output the product information;
}
}
}
我认为答案有点奇怪,但很简单:您的预期输出是错误的。 对我来说,您产生的输出似乎正确。
您使用的是弧度,而在预期的输出中,则使用度。
更改
private double theta = Math.toRadians(90.00);
至:
private double theta = 90;
给您预期的输出。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.