diff options
| author | Stanislaw Halik <sthalik@misaki.pl> | 2019-03-03 21:09:10 +0100 |
|---|---|---|
| committer | Stanislaw Halik <sthalik@misaki.pl> | 2019-03-03 21:10:13 +0100 |
| commit | f0238cfb6997c4acfc2bd200de7295f3fa36968f (patch) | |
| tree | b215183760e4f615b9c1dabc1f116383b72a1b55 /eigen/doc/tutorial.cpp | |
| parent | 543edd372a5193d04b3de9f23c176ab439e51b31 (diff) | |
don't index Eigen
Diffstat (limited to 'eigen/doc/tutorial.cpp')
| -rw-r--r-- | eigen/doc/tutorial.cpp | 62 |
1 files changed, 0 insertions, 62 deletions
diff --git a/eigen/doc/tutorial.cpp b/eigen/doc/tutorial.cpp deleted file mode 100644 index 62be7c2..0000000 --- a/eigen/doc/tutorial.cpp +++ /dev/null @@ -1,62 +0,0 @@ -#include <Eigen/Array> - -int main(int argc, char *argv[]) -{ - std::cout.precision(2); - - // demo static functions - Eigen::Matrix3f m3 = Eigen::Matrix3f::Random(); - Eigen::Matrix4f m4 = Eigen::Matrix4f::Identity(); - - std::cout << "*** Step 1 ***\nm3:\n" << m3 << "\nm4:\n" << m4 << std::endl; - - // demo non-static set... functions - m4.setZero(); - m3.diagonal().setOnes(); - - std::cout << "*** Step 2 ***\nm3:\n" << m3 << "\nm4:\n" << m4 << std::endl; - - // demo fixed-size block() expression as lvalue and as rvalue - m4.block<3,3>(0,1) = m3; - m3.row(2) = m4.block<1,3>(2,0); - - std::cout << "*** Step 3 ***\nm3:\n" << m3 << "\nm4:\n" << m4 << std::endl; - - // demo dynamic-size block() - { - int rows = 3, cols = 3; - m4.block(0,1,3,3).setIdentity(); - std::cout << "*** Step 4 ***\nm4:\n" << m4 << std::endl; - } - - // demo vector blocks - m4.diagonal().block(1,2).setOnes(); - std::cout << "*** Step 5 ***\nm4.diagonal():\n" << m4.diagonal() << std::endl; - std::cout << "m4.diagonal().start(3)\n" << m4.diagonal().start(3) << std::endl; - - // demo coeff-wise operations - m4 = m4.cwise()*m4; - m3 = m3.cwise().cos(); - std::cout << "*** Step 6 ***\nm3:\n" << m3 << "\nm4:\n" << m4 << std::endl; - - // sums of coefficients - std::cout << "*** Step 7 ***\n m4.sum(): " << m4.sum() << std::endl; - std::cout << "m4.col(2).sum(): " << m4.col(2).sum() << std::endl; - std::cout << "m4.colwise().sum():\n" << m4.colwise().sum() << std::endl; - std::cout << "m4.rowwise().sum():\n" << m4.rowwise().sum() << std::endl; - - // demo intelligent auto-evaluation - m4 = m4 * m4; // auto-evaluates so no aliasing problem (performance penalty is low) - Eigen::Matrix4f other = (m4 * m4).lazy(); // forces lazy evaluation - m4 = m4 + m4; // here Eigen goes for lazy evaluation, as with most expressions - m4 = -m4 + m4 + 5 * m4; // same here, Eigen chooses lazy evaluation for all that. - m4 = m4 * (m4 + m4); // here Eigen chooses to first evaluate m4 + m4 into a temporary. - // indeed, here it is an optimization to cache this intermediate result. - m3 = m3 * m4.block<3,3>(1,1); // here Eigen chooses NOT to evaluate block() into a temporary - // because accessing coefficients of that block expression is not more costly than accessing - // coefficients of a plain matrix. - m4 = m4 * m4.transpose(); // same here, lazy evaluation of the transpose. - m4 = m4 * m4.transpose().eval(); // forces immediate evaluation of the transpose - - std::cout << "*** Step 8 ***\nm3:\n" << m3 << "\nm4:\n" << m4 << std::endl; -} |
