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authorStanislaw Halik <sthalik@misaki.pl>2019-03-03 21:09:10 +0100
committerStanislaw Halik <sthalik@misaki.pl>2019-03-03 21:10:13 +0100
commitf0238cfb6997c4acfc2bd200de7295f3fa36968f (patch)
treeb215183760e4f615b9c1dabc1f116383b72a1b55 /eigen/doc/tutorial.cpp
parent543edd372a5193d04b3de9f23c176ab439e51b31 (diff)
don't index Eigen
Diffstat (limited to 'eigen/doc/tutorial.cpp')
-rw-r--r--eigen/doc/tutorial.cpp62
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;
-}