(十一)pcl-eigen篇-基本运算

参考：https://www.cnblogs.com/rainbow70626/p/8819119.html

#include <iostream>
#include <Eigen/Dense>
using namespace Eigen;
using namespace std;
int main()
{
    MatrixXf a(4, 1);
    a = MatrixXf::Zero(4, 1);//初始化为0
    cout << "初始化为0" << endl << a << endl;

    a = MatrixXf::Ones(4, 1);//初始化为1，矩阵大小与初始化相关，因为是动态矩阵
    cout << "初始化为1" << endl << a << endl;

    a.setZero();//矩阵置零
    cout << "矩阵置零" << endl << a << endl;

    a << 1, 2, 3, 4;//手动赋值

    MatrixXf b(1, 4);
    b.setRandom();//随机生成一个矩阵
    MatrixXf c(3, 3);
    c.setIdentity();
    cout << "置单位矩阵：" << endl << c << endl;
    c.setRandom();
    cout << "置随机矩阵：" << endl << c << endl;

    MatrixXf d = c;
    d = d.inverse();
    cout << "置矩阵的逆：" << endl << d << endl;

    cout << "矩阵a：" << endl << a << endl;
    cout << "矩阵b：" << b << endl;
    cout << "矩阵c：" << endl << c << endl;

    cout << "访问a(0)：" << endl << a(0) << endl;
    cout << "矩阵相乘：" << endl << a * b << endl;
    cout << "矩阵数乘：" << endl << 2 * a << endl;
    cout << "矩阵c求逆d：" << endl << d << endl;
    cout << "逆矩阵回乘：" << endl << d * c << endl;
    cout << "逆矩阵d转置：" << endl << d.transpose() << endl;
    Vector3d v(1, 2, 3);
    Vector3d w(1, 0, 0);
    cout << "向量相加：" << endl << v + w << endl;
    return 0;
}

输出：

初始化为0
0
0
0
0
初始化为1
1
1
1
1
矩阵置零
0
0
0
0
置单位矩阵：
1 0 0
0 1 0
0 0 1
置随机矩阵：
  0.170019   0.791925  -0.651784
-0.0402539    0.64568   0.717887
 -0.299417    0.49321   0.421003
置矩阵的逆：
 0.289714   2.30709  -3.48548
 0.697552  0.435359  0.337562
-0.611145   1.13077  -0.49905
矩阵a：
1
2
3
4
矩阵b：-0.997497  0.127171 -0.613392  0.617481
矩阵c：
  0.170019   0.791925  -0.651784
-0.0402539    0.64568   0.717887
 -0.299417    0.49321   0.421003
访问a(0)：
1
矩阵相乘：
-0.997497  0.127171 -0.613392  0.617481
 -1.99499  0.254341  -1.22678   1.23496
 -2.99249  0.381512  -1.84017   1.85244
 -3.98999  0.508683  -2.45357   2.46992
矩阵数乘：
2
4
6
8
矩阵c求逆d：
 0.289714   2.30709  -3.48548
 0.697552  0.435359  0.337562
-0.611145   1.13077  -0.49905
逆矩阵回乘：
           1            0            0
 7.45058e-09            1 -4.47035e-08
           0 -4.47035e-08            1
逆矩阵d转置：
 0.289714  0.697552 -0.611145
  2.30709  0.435359   1.13077
 -3.48548  0.337562  -0.49905
向量相加：
2
2
3