eigen/doc/snippets/MatrixBase_eval.cpp
Benoit Jacob 78ba523d30 Make snippet run successfully again:
the snippet for 'eval' was taking m=m.transpose() as an example of code
 that needs an explicit call to eval(), but that doesn't work anymore now
 that we have the clever assert detecting aliasing issues.
2010-01-04 21:23:37 -05:00

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C++

Matrix2f M = Matrix2f::Random();
Matrix2f m;
m = M;
cout << "Here is the matrix m:" << endl << m << endl;
cout << "Now we want to copy a column into a row." << endl;
cout << "If we do m.col(1) = m.row(0), then m becomes:" << endl;
m.col(1) = m.row(0);
cout << m << endl << "which is wrong!" << endl;
cout << "Now let us instead do m.col(1) = m.row(0).eval(). Then m becomes" << endl;
m = M;
m.col(1) = m.row(0).eval();
cout << m << endl << "which is right." << endl;