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<ArrayXf>(A.data(), A.size()), // concatenate matrices into a 1d array
Map<ArrayXf>(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