21 lines
764 B
C++
21 lines
764 B
C++
#include <Eigen/Core>
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#include <iostream>
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template <typename Derived>
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Eigen::Block<Derived> topLeftCorner(Eigen::MatrixBase<Derived>& m, int rows, int cols) {
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return Eigen::Block<Derived>(m.derived(), 0, 0, rows, cols);
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}
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template <typename Derived>
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const Eigen::Block<const Derived> topLeftCorner(const Eigen::MatrixBase<Derived>& m, int rows, int cols) {
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return Eigen::Block<const Derived>(m.derived(), 0, 0, rows, cols);
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}
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int main(int, char**) {
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Eigen::Matrix4d m = Eigen::Matrix4d::Identity();
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std::cout << topLeftCorner(4 * m, 2, 3) << std::endl; // calls the const version
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topLeftCorner(m, 2, 3) *= 5; // calls the non-const version
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std::cout << "Now the matrix m is:" << std::endl << m << std::endl;
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return 0;
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}
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