Solve linear equation by OpenCV.

solve.cpp

#include <iostream>
#include <opencv2/opencv.hpp>

int main() {
	// solve the equations below. 
	// x+y+z=6
	// x-y-z=-4
	// x+y+2z=9
	cv::Mat1f coef_mat(3, 4);
	cv::Mat1f answer(3, 1);

	coef_mat(0, 0) = 1;
	coef_mat(0, 1) = 1;
	coef_mat(0, 2) = 1;
	coef_mat(0, 3) = 6;

	coef_mat(1, 0) = 1;
	coef_mat(1, 1) = -1;
	coef_mat(1, 2) = -1;
	coef_mat(1, 3) = -4;

	coef_mat(2, 0) = 1;
	coef_mat(2, 1) = 1;
	coef_mat(2, 2) = 2;
	coef_mat(2, 3) = 9;

	cv::solve(
		cv::Mat(coef_mat, cv::Rect(0, 0, 3, 3)), 
		cv::Mat(coef_mat, cv::Rect(3, 0, 1, 3)), 
		answer);

	std::cout << answer << std::endl;

	return 0;
}