Eigen库学习笔记（九）矩阵拼接

• 1、矩阵拼接

void test_Concatenation()
{
	// Concatenation(vectors)
	Array3f a{ 1,1,1 };
	Array3f b{ 2,2,2 };
	cout << "a:n" << a << std::endl;
	cout << "b:n" << b << std::endl;
	ArrayXf c(a.size() + b.size());
	c << a, b;                              // np.concatenate((a,b))
	cout << "c:n" << c << std::endl;
	// Concatenation(matrix)
	int rows = 3;
	int cols = 3;
	ArrayXXf A = ArrayXXf::Constant(rows, cols, 1.0f);
	ArrayXXf B = ArrayXXf::Constant(rows, cols, 2.0f);

	ArrayXXf BindRows(A.rows() + B.rows(), cols);
	BindRows << A, B;                        // np.concatenate((A,B), axis=0)  
											// or np.vstack((a,b))
	cout << "A:n" << A << std::endl;
	cout << "B:n" << B << std::endl;
	cout << "BindRows:n" << BindRows << std::endl;
	ArrayXXf BindCols(rows, A.cols() + B.cols());
	BindCols << A, B;                        // np.concatenate((A,B), axis=1) 
											// or np.hstack((a,b))
	cout << "BindCols:n" << BindCols << std::endl;
	ArrayXf C(A.size() + B.size());         // np.concatenate((a,b), axis=None)
	C << Map(A.data(), A.size()),  // concatenate matrices into a 1d array
		Map(B.data(), B.size());
	cout << "C:n" << C << std::endl;

}

测试输出：

a:
1
1
1
b:
2
2
2
c:
1
1
1
2
2
2
A:
1 1 1
1 1 1
1 1 1
B:
2 2 2
2 2 2
2 2 2
BindRows:
1 1 1
1 1 1
1 1 1
2 2 2
2 2 2
2 2 2
BindCols:
1 1 1 2 2 2
1 1 1 2 2 2
1 1 1 2 2 2
C:
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2

参考：Eigen 简明教程之如何从Python转到Eigen
参考：Eigen how to concatenate matrix along a specific dimension?