27 lines
768 B
C++
27 lines
768 B
C++
#include <Eigen/Core.h>
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USING_PART_OF_NAMESPACE_EIGEN
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using namespace std;
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template<typename Scalar, typename Derived>
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Eigen::DynBlock<Derived>
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topLeftCorner(MatrixBase<Scalar, Derived>& m, int rows, int cols)
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{
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return Eigen::DynBlock<Derived>(m.ref(), 0, 0, rows, cols);
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}
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template<typename Scalar, typename Derived>
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const Eigen::DynBlock<Derived>
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topLeftCorner(const MatrixBase<Scalar, Derived>& m, int rows, int cols)
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{
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return Eigen::DynBlock<Derived>(m.ref(), 0, 0, rows, cols);
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}
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int main(int, char**)
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{
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Matrix4d m = Matrix4d::identity();
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cout << topLeftCorner(4*m, 2, 3) << endl; // calls the const version
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topLeftCorner(m, 2, 3) *= 5; // 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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