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- typedef Matrix<float,1,Dynamic> MatrixType;
- typedef Map<MatrixType> MapType;
- typedef Map<const MatrixType> MapTypeConst; // a read-only map
- const int n_dims = 5;
-
- MatrixType m1(n_dims), m2(n_dims);
- m1.setRandom();
- m2.setRandom();
- float *p = &m2(0); // get the address storing the data for m2
- MapType m2map(p,m2.size()); // m2map shares data with m2
- MapTypeConst m2mapconst(p,m2.size()); // a read-only accessor for m2
- cout << "m1: " << m1 << endl;
- cout << "m2: " << m2 << endl;
- cout << "Squared euclidean distance: " << (m1-m2).squaredNorm() << endl;
- cout << "Squared euclidean distance, using map: " <<
- (m1-m2map).squaredNorm() << endl;
- m2map(3) = 7; // this will change m2, since they share the same array
- cout << "Updated m2: " << m2 << endl;
- cout << "m2 coefficient 2, constant accessor: " << m2mapconst(2) << endl;
- /* m2mapconst(2) = 5; */ // this yields a compile-time error
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