Difference between revisions of "User:Tellenbach/3.4"
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Tellenbach (Talk | contribs) (Created page with "=== Changes that might impact existing code === * Using float or double for indexing matrices, vectors and array will now fail to compile, ex.: <source lang="cpp"> MatrixXd A...") |
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Vector4<MyType> V; // Instead of Vector<4, MyType> | Vector4<MyType> V; // Instead of Vector<4, MyType> | ||
</source> | </source> | ||
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=== New Backends === | === New Backends === | ||
* '''Arm SVE:''' Eigen now supports Arm's [https://developer.arm.com/documentation/101726/0300/Learn-about-the-Scalable-Vector-Extension--SVE-/What-is-the-Scalable-Vector-Extension- Scalable Vector Extension (SVE)]. Currently only fixed-lenght SVE vectors for <code>uint32_t</code> and <code>float</code> are available. | * '''Arm SVE:''' Eigen now supports Arm's [https://developer.arm.com/documentation/101726/0300/Learn-about-the-Scalable-Vector-Extension--SVE-/What-is-the-Scalable-Vector-Extension- Scalable Vector Extension (SVE)]. Currently only fixed-lenght SVE vectors for <code>uint32_t</code> and <code>float</code> are available. | ||
+ | |||
+ | === Improvements to Eigen Core === | ||
+ | |||
+ | * Eigen now uses c++11 '''alignas''' keyword for static alignment. Users targeting C++17 only and recent compilers (e.g., GCC>=7, clang>=5, MSVC>=19.12) will thus be able to completely forget about all [http://eigen.tuxfamily.org/dox-devel/group__TopicUnalignedArrayAssert.html issues] related to static alignment, including <code>EIGEN_MAKE_ALIGNED_OPERATOR_NEW</code>. | ||
+ | * Various performance improvements for products and Eigen's GEBP and GEMV kernels have been implemented: | ||
+ | ** By using half- and quater-packets the performance of matrix multiplications of small to medium sized matrices has been improved | ||
+ | ** Eigen's GEMM now falls back to GEMV if it detects that a matrix is a run-time vector | ||
+ | ** The performance of matrix products using Arm Neon has been drastically improved (up to 20%) |
Revision as of 21:30, 17 August 2021
Contents
Changes that might impact existing code
- Using float or double for indexing matrices, vectors and array will now fail to compile, ex.:
MatrixXd A(10,10); float one = 1; double a11 = A(one,1.); // compilation error here
New Major Features in Core
- Add c++11 initializer_list constructors to Matrix and Array [doc]:
MatrixXi a { // construct a 2x3 matrix {1,2,3}, // first row {4,5,6} // second row }; VectorXd v{{1, 2, 3, 4, 5}}; // construct a dynamic-size vector with 5 elements Array<int,1,5> a{1,2, 3, 4, 5}; // initialize a fixed-size 1D array of size 5.
- Add STL-compatible iterators for dense expressions [doc]. Some examples:
VectorXd v = ...; MatrixXd A = ...; // range for loop over all entries of v then A for(auto x : v) { cout << x << " "; } for(auto x : A.reshaped()) { cout << x << " "; } // sort v then each column of A std::sort(v.begin(), v.end()); for(auto c : A.colwise()) std::sort(c.begin(), c.end());
- Add C++11 template aliases for Matrix, Vector, and Array of common sizes, including generic
Vector<Type,Size>
andRowVector<Type,Size>
aliases [doc].
MatrixX<double> M; // Instead of MatrixXd or Matrix<Dynamic, Dynamic, double> Vector4<MyType> V; // Instead of Vector<4, MyType>
New Backends
- Arm SVE: Eigen now supports Arm's Scalable Vector Extension (SVE). Currently only fixed-lenght SVE vectors for
uint32_t
andfloat
are available.
Improvements to Eigen Core
- Eigen now uses c++11 alignas keyword for static alignment. Users targeting C++17 only and recent compilers (e.g., GCC>=7, clang>=5, MSVC>=19.12) will thus be able to completely forget about all issues related to static alignment, including
EIGEN_MAKE_ALIGNED_OPERATOR_NEW
. - Various performance improvements for products and Eigen's GEBP and GEMV kernels have been implemented:
- By using half- and quater-packets the performance of matrix multiplications of small to medium sized matrices has been improved
- Eigen's GEMM now falls back to GEMV if it detects that a matrix is a run-time vector
- The performance of matrix products using Arm Neon has been drastically improved (up to 20%)