diff options
author | Gael Guennebaud <g.gael@free.fr> | 2010-06-26 16:59:18 +0200 |
---|---|---|
committer | Gael Guennebaud <g.gael@free.fr> | 2010-06-26 16:59:18 +0200 |
commit | 5c866f2d8cbe54ec14627d5739b1645534a8fd1f (patch) | |
tree | 9dc1266fa727727fb134d8bbb1b2cbcd3d344beb /doc/QuickReference.dox | |
parent | 85c2c468df4a3e13271c8e0cfef49060325abfe2 (diff) |
started the quick reference tables
Diffstat (limited to 'doc/QuickReference.dox')
-rw-r--r-- | doc/QuickReference.dox | 648 |
1 files changed, 648 insertions, 0 deletions
diff --git a/doc/QuickReference.dox b/doc/QuickReference.dox new file mode 100644 index 000000000..63e5d5dcc --- /dev/null +++ b/doc/QuickReference.dox @@ -0,0 +1,648 @@ +namespace Eigen { + +/** \page QuickRefPage Quick reference guide + +\b Table \b of \b contents + - \ref QuickRef_Headers + - \ref QuickRef_Types + - \ref QuickRef_Map + - \ref QuickRef_ArithmeticOperators + - \ref QuickRef_Coeffwise +\n + +<hr> + +<a href="#" class="top">top</a> +\section QuickRef_Headers Modules and Header files + +<table class="tutorial_code"> +<tr><td>Module</td><td>Header file</td><td>Contents</td></tr> +<tr><td>Core</td><td>\code#include <Eigen/Core>\endcode</td><td>Matrix and Array classes, basic linear algebra (including triangular and selfadjoint products), array manipulation</td></tr> +<tr><td>Geometry</td><td>\code#include <Eigen/Geometry>\endcode</td><td>Transformation, Translation, Scaling, 2D and 3D rotations (Quaternion, AngleAxis)</td></tr> +<tr><td>LU</td><td>\code#include <Eigen/LU>\endcode</td><td>Inverse, determinant, LU decompositions (FullPivLU, PartialPivLU) with solver</td></tr> +<tr><td>Cholesky</td><td>\code#include <Eigen/Cholesky>\endcode</td><td>LLT and LDLT Cholesky factorization with solver</td></tr> +<tr><td>SVD</td><td>\code#include <Eigen/SVD>\endcode</td><td>SVD decomposition with solver (HouseholderSVD, JacobiSVD)</td></tr> +<tr><td>QR</td><td>\code#include <Eigen/QR>\endcode</td><td>QR decomposition with solver (HouseholderQR, ColPivHouseholerQR, FullPivHouseholderQR)</td></tr> +<tr><td>Eigenvalues</td><td>\code#include <Eigen/Eigenvalues>\endcode</td><td>Eigenvalue, eigenvector decompositions for selfadjoint and non selfadjoint real or complex matrices.</td></tr> +<tr><td>Sparse</td><td>\code#include <Eigen/Sparse>\endcode</td><td>Sparse matrix storage and related basic linear algebra.</td></tr> +<tr><td></td><td>\code#include <Eigen/Dense>\endcode</td><td>Includes Core, Geometry, LU, Cholesky, SVD, QR, and Eigenvalues</td></tr> +<tr><td></td><td>\code#include <Eigen/Eigen>\endcode</td><td>Includes Dense and Sparse</td></tr> +</table> + +<a href="#" class="top">top</a> +\section QuickRef_Types Array, matrix and vector types + +\b Recall: Eigen provides two kinds of dense objects: mathematical matrices and vectors which are both represented by the template class Matrix, and general 1D and 2D arrays represented by the template class Array: +\code +typedef Matrix<Scalar, RowsAtCompileTime, ColsAtCompileTime, Options> MyMatrixType; +typedef Array<Scalar, RowsAtCompileTime, ColsAtCompileTime, Options> MyArrayType; +\endcode + +\li \c Scalar is the scalar type of the coefficients (e.g., \c float, \c double, \c bool, \c int, etc.). +\li \c RowsAtCompileTime and \c ColsAtCompileTime are the number of rows and columns of the matrix as known at compile-time or \c Dynamic. +\li \c Options can be \c ColMajor or \c RowMajor, default is \c ColMajor. (see class Matrix for more options) + +All combinations are allowed: you can have a matrix with a fixed number of rows and a dynamic number of columns, etc. The following are all valid: + +\code +Matrix<double, 6, Dynamic> // Dynamic number of columns (heap allocation) +Matrix<double, Dynamic, 2> // Dynamic number of rows (heap allocation) +Matrix<double, Dynamic, Dynamic, RowMajor> // Fully dynamic, row major (heap allocation) +Matrix<double, 13, 3> // Fully fixed (static allocation) +\endcode + +In most cases, you can simply use one of the convenience typedefs for \ref matrixtypedefs "matrices" and \ref arraytypedefs "arrays". Some examples: +<table class="tutorial_code"> +<tr><td>\code +Matrix<float,Dynamic,Dynamic> <=> MatrixXf +Matrix<double,Dynamic,1> <=> VectorXd +Matrix<int,1,Dynamic> <=> RowVectorXi +Matrix<float,3,3> <=> Matrix3f +Matrix<float,4,1> <=> Vector4f +\endcode</td><td>\code +Array<float,Dynamic,Dynamic> <=> ArrayXXf +Array<double,Dynamic,1> <=> ArrayXd +Array<int,1,Dynamic> <=> RowArrayXi +Array<float,3,3> <=> Array33f +Array<float,4,1> <=> Array4f +\endcode</td></tr> +</table> + +Conversion between the matrix and array worlds: +\code +Array44f a1, a1; +Matrix4f m1, m2; +m1 = a1 * a2; // OK, coeffwise product +a1 = m1 * m2; // OK, matrix product +a2 = a1 + m1.array(); +m2 = a1.matrix() + m1; +ArrayWrapper<Matrix4f> m1a(m1); // m1a is an alias for m1.array(), they share the same coefficients +MatrixWrapper<Array44f> a1m(a1); +\endcode + +In the rest of this document we will use the following symbols to emphasize the features which are specifics to a given kind of object: +\li <a name="matrixonly"><a/>\matrixworld linear algebra matrix and vector only +\li <a name="arrayonly"><a/>\arrayworld array objects only + + +\subsection QuickRef_Basics Basic matrix manipulation + +<table class="tutorial_code"> +<tr><td></td><td>1D objects</td><td>2D objects</td><td>Notes</td></tr> +<tr><td>Constructors</td> +<td>\code +Vector4d v4; +Vector2f v1(x, y); +Array3i v2(x, y, z); +Vector4d v3(x, y, z, w); + +VectorXf v5; +ArrayXf v6(size); +\endcode</td><td>\code +Matrix4f m1; + + + + +MatrixXf m5; +MatrixXf m6(nb_rows, nb_columns); +\endcode</td><td> +The coeffs are left uninitialized \n \n + \n \n Empty object \n The coeffs are left uninitialized</td></tr> +<tr><td>Comma initializer</td> +<td>\code +Vector3f v1; v1 << x, y, z; +ArrayXf v2(4); v2 << 1, 2, 3, 4; + +\endcode</td><td>\code +Matrix3f m1; m1 << 1, 2, 3, + 4, 5, 6, + 7, 8, 9; +\endcode</td><td></td></tr> + +<tr><td>Comma initializer (bis)</td> +<td colspan="2"> +<table class="noborder"><tr><td> +\include Tutorial_commainit_02.cpp +</td> +<td> +output: +\verbinclude Tutorial_commainit_02.out +</td></tr></table> +<td></td></tr> + +<tr><td>Runtime info</td> +<td>\code +vector.size(); + +vector.innerStride(); +vector.data(); +\endcode</td><td>\code +matrix.rows(); matrix.cols(); +matrix.innerSize(); matrix.outerSize(); +matrix.innerStride(); matrix.outerStride(); +matrix.data(); +\endcode</td><td>\n Inner/Outer* are storage order dependent</td></tr> +<tr><td>Compile-time info</td> +<td colspan="2">\code +ObjectType::Scalar ObjectType::RowsAtCompileTime +ObjectType::RealScalar ObjectType::ColsAtCompileTime +ObjectType::Index ObjectType::SizeAtCompileTime +\endcode</td><td></td></tr> +<tr><td>Resizing</td> +<td>\code +vector.resize(size); + + +vector.resizeLike(other_vector); +vector.conservativeResize(size); +\endcode</td><td>\code +matrix.resize(nb_rows, nb_cols); +matrix.resize(Eigen::NoChange, nb_cols); +matrix.resize(nb_rows, Eigen::NoChange); +matrix.resizeLike(other_matrix); +matrix.conservativeResize(nb_rows, nb_cols); +\endcode</td><td></td>no-op if the new sizes match,\n otherwise data are lost \n \n resizing with data preservation</tr> + +<tr><td>Coeff access with \n range checking</td> +<td>\code +vector(i) vector.x() +vector[i] vector.y() + vector.z() + vector.w() +\endcode</td><td>\code +matrix(i,j) +\endcode</td><td><em class="note">Range checking is disabled if \n NDEBUG or EIGEN_NO_DEBUG is defined</em></td></tr> + +<tr><td>Coeff access without \n range checking</td> +<td>\code +vector.coeff(i) +vector.coeffRef(i) +\endcode</td><td>\code +matrix.coeff(i,j) +matrix.coeffRef(i,j) +\endcode</td><td></td></tr> + +<tr><td>Assignment/copy</td> +<td colspan="2">\code +object = expression; +object_of_float = expression_of_double.cast<float>(); +\endcode</td><td>the destination is automatically resized (if possible)</td></tr> + +</table> + +\subsection QuickRef_PredefMat Predefined Matrices + +<table class="tutorial_code"> +<tr> + <td>Fixed-size matrix or vector</td> + <td>Dynamic-size matrix</td> + <td>Dynamic-size vector</td> +</tr> +<tr style="border-bottom-style: none;"> + <td> +\code +typedef {Matrix3f|Array33f} FixedXD; +FixedXD x; + +x = FixedXD::Zero(); +x = FixedXD::Ones(); +x = FixedXD::Constant(value); +x = FixedXD::Random(); + +x.setZero(); +x.setOnes(); +x.setConstant(value); +x.setRandom(); +\endcode + </td> + <td> +\code +typedef {MatrixXf|ArrayXXf} Dynamic2D; +Dynamic2D x; + +x = Dynamic2D::Zero(rows, cols); +x = Dynamic2D::Ones(rows, cols); +x = Dynamic2D::Constant(rows, cols, value); +x = Dynamic2D::Random(rows, cols); + +x.setZero(rows, cols); +x.setOnes(rows, cols); +x.setConstant(rows, cols, value); +x.setRandom(rows, cols); +\endcode + </td> + <td> +\code +typedef {VectorXf|ArrayXf} Dynamic1D; +Dynamic1D x; + +x = Dynamic1D::Zero(size); +x = Dynamic1D::Ones(size); +x = Dynamic1D::Constant(size, value); +x = Dynamic1D::Random(size); + +x.setZero(size); +x.setOnes(size); +x.setConstant(size, value); +x.setRandom(size); +\endcode + </td> +</tr> + +<tr><td colspan="3">Identity and \link MatrixBase::Unit basis vectors \endlink \matrixworld</td></tr> +<tr style="border-bottom-style: none;"> + <td> +\code +x = FixedXD::Identity(); +x.setIdentity(); + +Vector3f::UnitX() // 1 0 0 +Vector3f::UnitY() // 0 1 0 +Vector3f::UnitZ() // 0 0 1 +\endcode + </td> + <td> +\code +x = Dynamic2D::Identity(rows, cols); +x.setIdentity(rows, cols); + + + +N/A +\endcode + </td> + <td>\code +N/A + + +VectorXf::Unit(size,i) +VectorXf::Unit(4,1) == Vector4f(0,1,0,0) + == Vector4f::UnitY() +\endcode + </td> +</tr> +</table> + + + +\subsection QuickRef_Map Map + +<table class="tutorial_code"> +<tr> +<td>Contiguous memory</td> +<td>\code +float data[] = {1,2,3,4}; +Map<Vector3f> v1(data); // uses v1 as a Vector3f object +Map<ArrayXf> v2(data,3); // uses v2 as a ArrayXf object +Map<Array22f> m1(data); // uses m1 as a Array22f object +Map<MatrixXf> m2(data,2,2); // uses m2 as a MatrixXf object +\endcode</td> +</tr> +<tr> +<td>Typical usage of strides</td> +<td>\code +float data[] = {1,2,3,4,5,6,7,8,9}; +Map<VectorXf,0,InnerStride<2> > v1(data,3); // == [1,3,5] +Map<VectorXf,0,InnerStride<> > v2(data,3,InnerStride<>(3)); // == [1,4,7] +Map<MatrixXf,0,OuterStride<> > m1(data,2,3,OuterStride<>(3)); // == |1,4,7| +Map<MatrixXf,0,OuterStride<3> > m2(data,2,3); // |2,5,8| +\endcode</td> +</tr> +</table> + + +<a href="#" class="top">top</a> +\section QuickRef_ArithmeticOperators Arithmetic Operators + +<table class="tutorial_code"> +<tr><td> +add/subtract</td><td>\code +mat3 = mat1 + mat2; mat3 += mat1; +mat3 = mat1 - mat2; mat3 -= mat1;\endcode +</td></tr> +<tr><td> +scalar product</td><td>\code +mat3 = mat1 * s1; mat3 = s1 * mat1; mat3 *= s1; +mat3 = mat1 / s1; mat3 /= s1;\endcode +</td></tr> +<tr><td> +matrix/vector product \matrixworld</td><td>\code +col2 = mat1 * col1; +row2 = row1 * mat1; row1 *= mat1; +mat3 = mat1 * mat2; mat3 *= mat1; \endcode +</td></tr> +<tr><td> +\link MatrixBase::dot() dot \endlink \& inner products \matrixworld</td><td>\code +scalar = col1.adjoint() * col2; +scalar = (col1.adjoint() * col2).value(); +scalar = vec1.dot(vec2);\endcode +</td></tr> +<tr><td> +outer product \matrixworld</td><td>\code +mat = col1 * col2.transpose();\endcode +</td></tr> +<tr><td> +\link MatrixBase::cross() cross product \endlink \matrixworld</td><td>\code +#include <Eigen/Geometry> +vec3 = vec1.cross(vec2);\endcode</td></tr> +</table> + +<a href="#" class="top">top</a> +\section QuickRef_Coeffwise Coefficient-wise \& Array operators +Coefficient-wise operators for matrices and vectors: +<table class="tutorial_code"> +<tr><td>Matrix API \matrixworld</td><td>Via Array conversions</td></tr> +<tr><td>\code +mat1.cwiseMin(mat2) +mat1.cwiseMax(mat2) +mat1.cwiseAbs2() +mat1.cwiseAbs() +mat1.cwiseSqrt() +mat1.cwiseProduct(mat2) +mat1.cwiseQuotient(mat2)\endcode +</td><td>\code +mat1.array().min(mat2.array()) +mat1.array().max(mat2.array()) +mat1.array().abs2() +mat1.array().abs() +mat1.array().sqrt() +mat1.array() * mat2.array() +mat1.array() / mat2.array() +\endcode</td></tr> +</table> + +Array operators:\arrayworld + +<table class="tutorial_code"> +<tr><td>Arithmetic operators</td><td>\code +array1 * array2 array1 / array2 array1 *= array2 array1 /= array2 +array1 + scalar array1 - scalar array1 += scalar array1 -= scalar +\endcode</td></tr> +<tr><td>Comparisons</td><td>\code +array1 < array2 array1 > array2 array1 < scalar array1 > scalar +array1 <= array2 array1 >= array2 array1 <= scalar array1 >= scalar +array1 == array2 array1 != array2 array1 == scalar array1 != scalar +\endcode</td></tr> +<tr><td>Special functions \n and STL variants</td><td>\code +array1.min(array2) std::min(array1,array2) +array1.max(array2) std::max(array1,array2) +array1.abs2() +array1.abs() std::abs(array1) +array1.sqrt() std::sqrt(array1) +array1.log() std::log(array1) +array1.exp() std::exp(array1) +array1.pow(exponent) std::pow(array1,exponent) +array1.square() +array1.cube() +array1.inverse() +array1.sin() std::sin(array1) +array1.cos() std::cos(array1) +array1.tan() std::tan(array1) +\endcode +</td></tr> +</table> + +*/ + +// FIXME I stopped here + +/** +<a href="#" class="top">top</a> +\section TutorialCoreReductions Reductions + +Eigen provides several reduction methods such as: +\link DenseBase::minCoeff() minCoeff() \endlink, \link DenseBase::maxCoeff() maxCoeff() \endlink, +\link DenseBase::sum() sum() \endlink, \link MatrixBase::trace() trace() \endlink \matrixworld, +\link MatrixBase::norm() norm() \endlink \matrixworld, \link MatrixBase::squaredNorm() squaredNorm() \endlink \matrixworld, +\link DenseBase::all() all() \endlink \redstar,and \link DenseBase::any() any() \endlink \redstar. +All reduction operations can be done matrix-wise, +\link DenseBase::colwise() column-wise \endlink \redstar or +\link DenseBase::rowwise() row-wise \endlink \redstar. Usage example: +<table class="tutorial_code"> +<tr><td rowspan="3" style="border-right-style:dashed">\code + 5 3 1 +mat = 2 7 8 + 9 4 6 \endcode +</td> <td>\code mat.minCoeff(); \endcode</td><td>\code 1 \endcode</td></tr> +<tr><td>\code mat.colwise().minCoeff(); \endcode</td><td>\code 2 3 1 \endcode</td></tr> +<tr><td>\code mat.rowwise().minCoeff(); \endcode</td><td>\code +1 +2 +4 +\endcode</td></tr> +</table> + +Also note that maxCoeff and minCoeff can takes optional arguments returning the coordinates of the respective min/max coeff: \link DenseBase::maxCoeff(int*,int*) const maxCoeff(int* i, int* j) \endlink, \link DenseBase::minCoeff(int*,int*) const minCoeff(int* i, int* j) \endlink. + +<span class="note">\b Side \b note: The all() and any() functions are especially useful in combination with coeff-wise comparison operators.</span> + + + + + +<a href="#" class="top">top</a>\section TutorialCoreMatrixBlocks Matrix blocks + +Read-write access to a \link DenseBase::col(int) column \endlink +or a \link DenseBase::row(int) row \endlink of a matrix (or array): +\code +mat1.row(i) = mat2.col(j); +mat1.col(j1).swap(mat1.col(j2)); +\endcode + +Read-write access to sub-vectors: +<table class="tutorial_code"> +<tr> +<td>Default versions</td> +<td>Optimized versions when the size \n is known at compile time</td></tr> +<td></td> + +<tr><td>\code vec1.head(n)\endcode</td><td>\code vec1.head<n>()\endcode</td><td>the first \c n coeffs </td></tr> +<tr><td>\code vec1.tail(n)\endcode</td><td>\code vec1.tail<n>()\endcode</td><td>the last \c n coeffs </td></tr> +<tr><td>\code vec1.segment(pos,n)\endcode</td><td>\code vec1.segment<n>(pos)\endcode</td> + <td>the \c size coeffs in \n the range [\c pos : \c pos + \c n [</td></tr> +<tr style="border-style: dashed none dashed none;"><td> + +Read-write access to sub-matrices:</td><td></td><td></td></tr> +<tr> + <td>\code mat1.block(i,j,rows,cols)\endcode + \link DenseBase::block(int,int,int,int) (more) \endlink</td> + <td>\code mat1.block<rows,cols>(i,j)\endcode + \link DenseBase::block(int,int) (more) \endlink</td> + <td>the \c rows x \c cols sub-matrix \n starting from position (\c i,\c j)</td></tr><tr> + <td>\code + mat1.topLeftCorner(rows,cols) + mat1.topRightCorner(rows,cols) + mat1.bottomLeftCorner(rows,cols) + mat1.bottomRightCorner(rows,cols)\endcode + <td>\code + mat1.topLeftCorner<rows,cols>() + mat1.topRightCorner<rows,cols>() + mat1.bottomLeftCorner<rows,cols>() + mat1.bottomRightCorner<rows,cols>()\endcode + <td>the \c rows x \c cols sub-matrix \n taken in one of the four corners</td></tr> +</table> + + + +<a href="#" class="top">top</a>\section TutorialCoreDiagonalMatrices Diagonal matrices +\matrixworld + +<table class="tutorial_code"> +<tr><td> +\link MatrixBase::asDiagonal() make a diagonal matrix \endlink from a vector \n +<em class="note">this product is automatically optimized !</em></td><td>\code +mat3 = mat1 * vec2.asDiagonal();\endcode +</td></tr> +<tr><td>Access \link MatrixBase::diagonal() the diagonal of a matrix \endlink as a vector (read/write)</td> + <td>\code + vec1 = mat1.diagonal(); + mat1.diagonal() = vec1; + \endcode +</td> +</tr> +</table> + + + +<a href="#" class="top">top</a> +\section TutorialCoreTransposeAdjoint Transpose and Adjoint operations + +<table class="tutorial_code"> +<tr><td> +\link DenseBase::transpose() transposition \endlink (read-write)</td><td>\code +mat3 = mat1.transpose() * mat2; +mat3.transpose() = mat1 * mat2.transpose(); +\endcode +</td></tr> +<tr><td> +\link MatrixBase::adjoint() adjoint \endlink (read only) \matrixworld\n</td><td>\code +mat3 = mat1.adjoint() * mat2; +\endcode +</td></tr> +</table> + + + +<a href="#" class="top">top</a> +\section TutorialCoreDotNorm Dot-product, vector norm, normalization \matrixworld + +<table class="tutorial_code"> +<tr><td> +\link MatrixBase::dot() Dot-product \endlink of two vectors +</td><td>\code vec1.dot(vec2);\endcode +</td></tr> +<tr><td> +\link MatrixBase::norm() norm \endlink of a vector \n +\link MatrixBase::squaredNorm() squared norm \endlink of a vector +</td><td>\code vec.norm(); \endcode \n \code vec.squaredNorm() \endcode +</td></tr> +<tr><td> +returns a \link MatrixBase::normalized() normalized \endlink vector \n +\link MatrixBase::normalize() normalize \endlink a vector +</td><td>\code +vec3 = vec1.normalized(); +vec1.normalize();\endcode +</td></tr> +</table> + + + +<a href="#" class="top">top</a> +\section TutorialCoreTriangularMatrix Dealing with triangular matrices \matrixworld + +Currently, Eigen does not provide any explicit triangular matrix, with storage class. Instead, we +can reference a triangular part of a square matrix or expression to perform special treatment on it. +This is achieved by the class TriangularView and the MatrixBase::triangularView template function. +Note that the opposite triangular part of the matrix is never referenced, and so it can, e.g., store +a second triangular matrix. + +<table class="tutorial_code"> +<tr><td> +Reference a read/write triangular part of a given \n +matrix (or expression) m with optional unit diagonal: +</td><td>\code +m.triangularView<Eigen::UpperTriangular>() +m.triangularView<Eigen::UnitUpperTriangular>() +m.triangularView<Eigen::LowerTriangular>() +m.triangularView<Eigen::UnitLowerTriangular>()\endcode +</td></tr> +<tr><td> +Writing to a specific triangular part:\n (only the referenced triangular part is evaluated) +</td><td>\code +m1.triangularView<Eigen::LowerTriangular>() = m2 + m3 \endcode +</td></tr> +<tr><td> +Conversion to a dense matrix setting the opposite triangular part to zero: +</td><td>\code +m2 = m1.triangularView<Eigen::UnitUpperTriangular>()\endcode +</td></tr> +<tr><td> +Products: +</td><td>\code +m3 += s1 * m1.adjoint().triangularView<Eigen::UnitUpperTriangular>() * m2 +m3 -= s1 * m2.conjugate() * m1.adjoint().triangularView<Eigen::LowerTriangular>() \endcode +</td></tr> +<tr><td> +Solving linear equations:\n(\f$ m_2 := m_1^{-1} m_2 \f$) +</td><td>\code +m1.triangularView<Eigen::UnitLowerTriangular>().solveInPlace(m2) +m1.adjoint().triangularView<Eigen::UpperTriangular>().solveInPlace(m2)\endcode +</td></tr> +</table> + + + +<a href="#" class="top">top</a> +\section TutorialCoreSelfadjointMatrix Dealing with symmetric/selfadjoint matrices \matrixworld + +Just as for triangular matrix, you can reference any triangular part of a square matrix to see it a selfadjoint +matrix to perform special and optimized operations. Again the opposite triangular is never referenced and can be +used to store other information. + +<table class="tutorial_code"> +<tr><td> +Conversion to a dense matrix: +</td><td>\code +m2 = m.selfadjointView<Eigen::LowerTriangular>();\endcode +</td></tr> +<tr><td> +Product with another general matrix or vector: +</td><td>\code +m3 = s1 * m1.conjugate().selfadjointView<Eigen::UpperTriangular>() * m3; +m3 -= s1 * m3.adjoint() * m1.selfadjointView<Eigen::UpperTriangular>();\endcode +</td></tr> +<tr><td> +Rank 1 and rank K update: +</td><td>\code +// fast version of m1 += s1 * m2 * m2.adjoint(): +m1.selfadjointView<Eigen::UpperTriangular>().rankUpdate(m2,s1); +// fast version of m1 -= m2.adjoint() * m2: +m1.selfadjointView<Eigen::LowerTriangular>().rankUpdate(m2.adjoint(),-1); \endcode +</td></tr> +<tr><td> +Rank 2 update: (\f$ m += s u v^* + s v u^* \f$) +</td><td>\code +m.selfadjointView<Eigen::UpperTriangular>().rankUpdate(u,v,s); +\endcode +</td></tr> +<tr><td> +Solving linear equations:\n(\f$ m_2 := m_1^{-1} m_2 \f$) +</td><td>\code +// via a standard Cholesky factorization +m1.selfadjointView<Eigen::UpperTriangular>().llt().solveInPlace(m2); +// via a Cholesky factorization with pivoting +m1.selfadjointView<Eigen::UpperTriangular>().ldlt().solveInPlace(m2); +\endcode +</td></tr> +</table> + + +<a href="#" class="top">top</a> +\section TutorialCoreSpecialTopics Special Topics + +\ref TopicLazyEvaluation "Lazy Evaluation and Aliasing": Thanks to expression templates, Eigen is able to apply lazy evaluation wherever that is beneficial. + +*/ + +} |