28 lines
697 B
C++
28 lines
697 B
C++
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#include <Eigen/Core>
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#include <iostream>
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using namespace Eigen;
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using namespace std;
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template<typename Derived>
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Eigen::Block<Derived, 2, 2>
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topLeft2x2Corner(MatrixBase<Derived>& m)
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{
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return Eigen::Block<Derived, 2, 2>(m.derived(), 0, 0);
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}
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template<typename Derived>
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const Eigen::Block<const Derived, 2, 2>
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topLeft2x2Corner(const MatrixBase<Derived>& m)
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{
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return Eigen::Block<const Derived, 2, 2>(m.derived(), 0, 0);
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}
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int main(int, char**)
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{
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Matrix3d m = Matrix3d::Identity();
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cout << topLeft2x2Corner(4*m) << endl; // calls the const version
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topLeft2x2Corner(m) *= 2; // calls the non-const version
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cout << "Now the matrix m is:" << endl << m << endl;
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return 0;
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}
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