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@ -315,6 +315,7 @@ template<typename T> inline T* ei_construct_elements_of_array(T *ptr, size_t siz
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template<typename T> inline void ei_destruct_elements_of_array(T *ptr, size_t size)
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{
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// always destruct an array starting from the end.
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if(ptr)
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while(size) ptr[--size].~T();
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}
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|
@ -65,7 +65,7 @@ void MatrixBase<Derived>::makeHouseholder(
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EIGEN_STATIC_ASSERT_VECTOR_ONLY(EssentialPart)
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VectorBlock<Derived, EssentialPart::SizeAtCompileTime> tail(derived(), 1, size()-1);
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RealScalar tailSqNorm = size()==1 ? 0 : tail.squaredNorm();
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RealScalar tailSqNorm = size()==1 ? RealScalar(0) : tail.squaredNorm();
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Scalar c0 = coeff(0);
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if(tailSqNorm == RealScalar(0) && ei_imag(c0)==RealScalar(0))
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|
@ -43,7 +43,7 @@ also have the same \c Scalar type, as Eigen doesn't do automatic type promotion.
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Example: \include tut_arithmetic_add_sub.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_add_sub.out
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Output: \verbinclude tut_arithmetic_add_sub.out
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</td></tr></table>
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\section TutorialArithmeticScalarMulDiv Scalar multiplication and division
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@ -59,7 +59,7 @@ Multiplication and division by a scalar is very simple too. The operators at han
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Example: \include tut_arithmetic_scalar_mul_div.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_scalar_mul_div.out
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Output: \verbinclude tut_arithmetic_scalar_mul_div.out
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</td></tr></table>
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@ -93,7 +93,7 @@ The transpose \f$ a^T \f$, conjugate \f$ \bar{a} \f$, and adjoint (i.e., conjuga
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Example: \include tut_arithmetic_transpose_conjugate.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_transpose_conjugate.out
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Output: \verbinclude tut_arithmetic_transpose_conjugate.out
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</td></tr></table>
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For real matrices, \c conjugate() is a no-operation, and so \c adjoint() is 100% equivalent to \c transpose().
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@ -103,7 +103,7 @@ As for basic arithmetic operators, \c transpose() and \c adjoint() simply return
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Example: \include tut_arithmetic_transpose_aliasing.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_transpose_aliasing.out
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Output: \verbinclude tut_arithmetic_transpose_aliasing.out
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</td></tr></table>
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This is the so-called \ref TopicAliasing "aliasing issue". In "debug mode", i.e., when \ref TopicAssertions "assertions" have not been disabled, such common pitfalls are automatically detected.
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@ -112,7 +112,7 @@ For \em in-place transposition, as for instance in <tt>a = a.transpose()</tt>, s
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Example: \include tut_arithmetic_transpose_inplace.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_transpose_inplace.out
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Output: \verbinclude tut_arithmetic_transpose_inplace.out
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</td></tr></table>
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There is also the \link MatrixBase::adjointInPlace() adjointInPlace()\endlink function for complex matrices.
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@ -129,7 +129,7 @@ two operators:
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Example: \include tut_arithmetic_matrix_mul.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_matrix_mul.out
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Output: \verbinclude tut_arithmetic_matrix_mul.out
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</td></tr></table>
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Note: if you read the above paragraph on expression templates and are worried that doing \c m=m*m might cause
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@ -154,7 +154,7 @@ The above-discussed \c operator* cannot be used to compute dot and cross product
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Example: \include tut_arithmetic_dot_cross.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_dot_cross.out
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Output: \verbinclude tut_arithmetic_dot_cross.out
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</td></tr></table>
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Remember that cross product is only for vectors of size 3. Dot product is for vectors of any sizes.
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@ -168,7 +168,7 @@ Eigen also provides some reduction operations to reduce a given matrix or vector
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Example: \include tut_arithmetic_redux_basic.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_redux_basic.out
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Output: \verbinclude tut_arithmetic_redux_basic.out
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</td></tr></table>
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The \em trace of a matrix, as returned by the function \link MatrixBase::trace() trace()\endlink, is the sum of the diagonal coefficients and can also be computed as efficiently using <tt>a.diagonal().sum()</tt>, as we will see later on.
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@ -179,7 +179,7 @@ There also exist variants of the \c minCoeff and \c maxCoeff functions returning
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Example: \include tut_arithmetic_redux_minmax.cpp
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</td>
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<td>
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Output: \include tut_arithmetic_redux_minmax.out
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Output: \verbinclude tut_arithmetic_redux_minmax.out
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</td></tr></table>
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|
@ -13,21 +13,22 @@ provided that you let your compiler optimize.
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\b Table \b of \b contents
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- \ref TutorialBlockOperationsUsing
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- \ref TutorialBlockOperationsSyntax
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- \ref TutorialBlockOperationsSyntaxColumnRows
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- \ref TutorialBlockOperationsSyntaxCorners
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- \ref TutorialBlockOperationsSyntaxVectors
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\section TutorialBlockOperationsUsing Using block operations
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The most general block operation in Eigen is called \link DenseBase::block() .block() \endlink.
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This function returns a block of size <tt>(p,q)</tt> whose origin is at <tt>(i,j)</tt> by using
|
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the following syntax:
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This function returns a block of size <tt>(p,q)</tt> whose origin is at <tt>(i,j)</tt>.
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There are two versions, whose syntax is as follows:
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<table class="tutorial_code" align="center">
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<tr><td align="center">\b Block \b operation</td>
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<td align="center">Default \b version</td>
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<tr><td align="center">\b %Block \b operation</td>
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<td align="center">Default version</td>
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<td align="center">Optimized version when the<br>size is known at compile time</td></tr>
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<tr><td>Block of size <tt>(p,q)</tt>, starting at <tt>(i,j)</tt></td>
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<tr><td>%Block of size <tt>(p,q)</tt>, starting at <tt>(i,j)</tt></td>
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<td>\code
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matrix.block(i,j,p,q);\endcode </td>
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<td>\code
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@ -35,7 +36,15 @@ matrix.block<p,q>(i,j);\endcode </td>
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</tr>
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</table>
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Therefore, if we want to print the values of a block inside a matrix we can simply write:
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The default version is a method which takes four arguments. It can always be used. The optimized version
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takes two template arguments (the size of the block) and two normal arguments (the position of the block).
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It can only be used if the size of the block is known at compile time, but it may be faster than the
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non-optimized version, especially if the size of the block is small. Both versions can be used on fixed-size
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and dynamic-size matrices and arrays.
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The following program uses the default and optimized versions to print the values of several blocks inside a
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matrix.
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<table class="tutorial_code"><tr><td>
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\include Tutorial_BlockOperations_print_block.cpp
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</td>
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@ -44,10 +53,15 @@ Output:
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\verbinclude Tutorial_BlockOperations_print_block.out
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</td></tr></table>
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In the above example the \link DenseBase::block() .block() \endlink function was employed
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to read the values inside matrix \p m . However, blocks can also be used as lvalues, meaning that you can
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assign to a block.
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In the previous example the \link DenseBase::block() .block() \endlink function was employed
|
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to read the values inside matrix \p m . Blocks can also be used to perform operations and
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assignments within matrices or arrays of different size:
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This is illustrated in the following example, which uses arrays instead of matrices. The coefficients of the
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5-by-5 array \c n are first all set to 0.6, but then the 3-by-3 block in the middle is set to the values in
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\c m . The penultimate line shows that blocks can be combined with matrices and arrays to create more complex
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expressions. Blocks of an array are an array expression, and thus the multiplication here is coefficient-wise
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multiplication.
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<table class="tutorial_code"><tr><td>
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\include Tutorial_BlockOperations_block_assignment.cpp
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@ -57,55 +71,38 @@ Output:
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\verbinclude Tutorial_BlockOperations_block_assignment.out
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</td></tr></table>
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The \link DenseBase::block() .block() \endlink method is used for general block operations, but there are
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other methods for special cases. These are described in the rest of this page.
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Blocks can also be combined with matrices and arrays to create more complex expressions:
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\code
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MatrixXf m(3,3), n(2,2);
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MatrixXf p(3,3);
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\section TutorialBlockOperationsSyntaxColumnRows Columns and rows
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m.block(0,0,2,2) = m.block(0,0,2,2) * n + p.block(1,1,2,2);
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\endcode
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It is important to point out that \link DenseBase::block() .block() \endlink is the
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general case for a block operation but there are many other useful block operations,
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as described in the next section.
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\section TutorialBlockOperationsSyntax Block operation syntax
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The following tables show a summary of Eigen's block operations and how they are applied to
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fixed- and dynamic-sized Eigen objects.
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\subsection TutorialBlockOperationsSyntaxColumnRows Columns and rows
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Other extremely useful block operations are \link DenseBase::col() .col() \endlink and
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\link DenseBase::row() .row() \endlink which provide access to a
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specific row or column. This is a special case in the sense that the syntax for fixed- and
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dynamic-sized objects is exactly the same:
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Individual columns and rows are special cases of blocks. Eigen provides methods to easily access them:
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\link DenseBase::col() .col() \endlink and \link DenseBase::row() .row()\endlink. There is no syntax variant
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for an optimized version.
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<table class="tutorial_code" align="center">
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<tr><td align="center">\b Block \b operation</td>
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<tr><td align="center">\b %Block \b operation</td>
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<td align="center">Default version</td>
|
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<td align="center">Optimized version when the<br>size is known at compile time</td></tr>
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<tr><td>i<sup>th</sup> row
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\link DenseBase::row() * \endlink</td>
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<td>\code
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MatrixXf m;
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std::cout << m.row(i);\endcode </td>
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matrix.row(i);\endcode </td>
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<td>\code
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Matrix3f m;
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std::cout << m.row(i);\endcode </td>
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matrix.row(i);\endcode </td>
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</tr>
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<tr><td>j<sup>th</sup> column
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\link DenseBase::col() * \endlink</td>
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<td>\code
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||||
MatrixXf m;
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std::cout << m.col(j);\endcode </td>
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matrix.col(j);\endcode </td>
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<td>\code
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Matrix3f m;
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std::cout << m.col(j);\endcode </td>
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matrix.col(j);\endcode </td>
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</tr>
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||||
</table>
|
||||
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A simple example demonstrating these feature follows:
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The argument for \p col() and \p row() is the index of the column or row to be accessed, starting at
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0. Therefore, \p col(0) will access the first column and \p col(1) the second one.
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|
||||
<table class="tutorial_code"><tr><td>
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||||
C++ code:
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||||
@ -113,94 +110,83 @@ C++ code:
|
||||
</td>
|
||||
<td>
|
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Output:
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\include Tutorial_BlockOperations_colrow.out
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\verbinclude Tutorial_BlockOperations_colrow.out
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</td></tr></table>
|
||||
|
||||
|
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\b NOTE: the argument for \p col() and \p row() is the index of the column or row to be accessed,
|
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starting at 0. Therefore, \p col(0) will access the first column and \p col(1) the second one.
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\section TutorialBlockOperationsSyntaxCorners Corner-related operations
|
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||||
Eigen also provides special methods for blocks that are flushed against one of the corners or sides of a
|
||||
matrix or array. For instance, \link DenseBase::topLeftCorner() .topLeftCorner() \endlink can be used to refer
|
||||
to a block in the top-left corner of a matrix. Use <tt>matrix.topLeftCorner(p,q)</tt> to access the block
|
||||
consisting of the coefficients <tt>matrix(i,j)</tt> with \c i < \c p and \c j < \c q. As an other
|
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example, blocks consisting of whole rows flushed against the top side of the matrix can be accessed by
|
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\link DenseBase::topRows() .topRows() \endlink.
|
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|
||||
The different possibilities are summarized in the following table:
|
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|
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\subsection TutorialBlockOperationsSyntaxCorners Corner-related operations
|
||||
<table class="tutorial_code" align="center">
|
||||
<tr><td align="center">\b Block \b operation</td>
|
||||
<tr><td align="center">\b %Block \b operation</td>
|
||||
<td align="center">Default version</td>
|
||||
<td align="center">Optimized version when the<br>size is known at compile time</td></tr>
|
||||
<tr><td>Top-left p by q block \link DenseBase::topLeftCorner() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
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std::cout << m.topLeftCorner(p,q);\endcode </td>
|
||||
matrix.topLeftCorner(p,q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
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std::cout << m.topLeftCorner<p,q>();\endcode </td>
|
||||
matrix.topLeftCorner<p,q>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Bottom-left p by q block
|
||||
\link DenseBase::bottomLeftCorner() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.bottomLeftCorner(p,q);\endcode </td>
|
||||
matrix.bottomLeftCorner(p,q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.bottomLeftCorner<p,q>();\endcode </td>
|
||||
matrix.bottomLeftCorner<p,q>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Top-right p by q block
|
||||
\link DenseBase::topRightCorner() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.topRightCorner(p,q);\endcode </td>
|
||||
matrix.topRightCorner(p,q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.topRightCorner<p,q>();\endcode </td>
|
||||
matrix.topRightCorner<p,q>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Bottom-right p by q block
|
||||
\link DenseBase::bottomRightCorner() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.bottomRightCorner(p,q);\endcode </td>
|
||||
matrix.bottomRightCorner(p,q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.bottomRightCorner<p,q>();\endcode </td>
|
||||
matrix.bottomRightCorner<p,q>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Block containing the first q rows
|
||||
<tr><td>%Block containing the first q rows
|
||||
\link DenseBase::topRows() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.topRows(q);\endcode </td>
|
||||
matrix.topRows(q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.topRows<q>();\endcode </td>
|
||||
matrix.topRows<q>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Block containing the last q rows
|
||||
<tr><td>%Block containing the last q rows
|
||||
\link DenseBase::bottomRows() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.bottomRows(q);\endcode </td>
|
||||
matrix.bottomRows(q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.bottomRows<q>();\endcode </td>
|
||||
matrix.bottomRows<q>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Block containing the first p columns
|
||||
<tr><td>%Block containing the first p columns
|
||||
\link DenseBase::leftCols() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.leftCols(p);\endcode </td>
|
||||
matrix.leftCols(p);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.leftCols<p>();\endcode </td>
|
||||
matrix.leftCols<p>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Block containing the last q columns
|
||||
<tr><td>%Block containing the last q columns
|
||||
\link DenseBase::rightCols() * \endlink</td>
|
||||
<td>\code
|
||||
MatrixXf m;
|
||||
std::cout << m.rightCols(q);\endcode </td>
|
||||
matrix.rightCols(q);\endcode </td>
|
||||
<td>\code
|
||||
Matrix3f m;
|
||||
std::cout << m.rightCols<q>();\endcode </td>
|
||||
matrix.rightCols<q>();\endcode </td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
Here is a simple example showing the power of the operations presented above:
|
||||
Here is a simple example illustrating the use of the operations presented above:
|
||||
|
||||
<table class="tutorial_code"><tr><td>
|
||||
C++ code:
|
||||
@ -208,49 +194,38 @@ C++ code:
|
||||
</td>
|
||||
<td>
|
||||
Output:
|
||||
\include Tutorial_BlockOperations_corner.out
|
||||
\verbinclude Tutorial_BlockOperations_corner.out
|
||||
</td></tr></table>
|
||||
|
||||
|
||||
\section TutorialBlockOperationsSyntaxVectors Block operations for vectors
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
\subsection TutorialBlockOperationsSyntaxVectors Block operations for vectors
|
||||
Eigen also provides a set of block operations designed specifically for vectors:
|
||||
Eigen also provides a set of block operations designed specifically for vectors and one-dimensional arrays:
|
||||
|
||||
<table class="tutorial_code" align="center">
|
||||
<tr><td align="center">\b Block \b operation</td>
|
||||
<tr><td align="center">\b %Block \b operation</td>
|
||||
<td align="center">Default version</td>
|
||||
<td align="center">Optimized version when the<br>size is known at compile time</td></tr>
|
||||
<tr><td>Block containing the first \p n elements
|
||||
<tr><td>%Block containing the first \p n elements
|
||||
\link DenseBase::head() * \endlink</td>
|
||||
<td>\code
|
||||
VectorXf v;
|
||||
std::cout << v.head(n);\endcode </td>
|
||||
vector.head(n);\endcode </td>
|
||||
<td>\code
|
||||
Vector3f v;
|
||||
std::cout << v.head<n>();\endcode </td>
|
||||
vector.head<n>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Block containing the last \p n elements
|
||||
<tr><td>%Block containing the last \p n elements
|
||||
\link DenseBase::tail() * \endlink</td>
|
||||
<td>\code
|
||||
VectorXf v;
|
||||
std::cout << v.tail(n);\endcode </td>
|
||||
vector.tail(n);\endcode </td>
|
||||
<td>\code
|
||||
Vector3f m;
|
||||
std::cout << v.tail<n>();\endcode </td>
|
||||
vector.tail<n>();\endcode </td>
|
||||
</tr>
|
||||
<tr><td>Block containing \p n elements, starting at position \p i
|
||||
<tr><td>%Block containing \p n elements, starting at position \p i
|
||||
\link DenseBase::segment() * \endlink</td>
|
||||
<td>\code
|
||||
VectorXf v;
|
||||
std::cout << v.segment(i,n);\endcode </td>
|
||||
vector.segment(i,n);\endcode </td>
|
||||
<td>\code
|
||||
Vector3f m;
|
||||
std::cout << v.segment<n>(i);\endcode </td>
|
||||
vector.segment<n>(i);\endcode </td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
@ -262,7 +237,7 @@ C++ code:
|
||||
</td>
|
||||
<td>
|
||||
Output:
|
||||
\include Tutorial_BlockOperations_vector.out
|
||||
\verbinclude Tutorial_BlockOperations_vector.out
|
||||
</td></tr></table>
|
||||
|
||||
\li \b Next: \ref TutorialAdvancedInitialization
|
||||
|
@ -30,7 +30,7 @@ which returns the addition of all the coefficients inside a given matrix or arra
|
||||
Example: \include tut_arithmetic_redux_basic.cpp
|
||||
</td>
|
||||
<td>
|
||||
Output: \include tut_arithmetic_redux_basic.out
|
||||
Output: \verbinclude tut_arithmetic_redux_basic.out
|
||||
</td></tr></table>
|
||||
|
||||
The \em trace of a matrix, as returned by the function \c trace(), is the sum of the diagonal coefficients and can also be computed as efficiently using <tt>a.diagonal().sum()</tt>, as we will see later on.
|
||||
|
@ -6,26 +6,13 @@ using namespace Eigen;
|
||||
|
||||
int main()
|
||||
{
|
||||
MatrixXf m(3,3), n(2,2);
|
||||
|
||||
Array33f m;
|
||||
m << 1,2,3,
|
||||
4,5,6,
|
||||
7,8,9;
|
||||
|
||||
// assignment through a block operation,
|
||||
// block as rvalue
|
||||
n = m.block(0,0,2,2);
|
||||
|
||||
//print n
|
||||
Array<float,5,5> n = Array<float,5,5>::Constant(0.6);
|
||||
n.block(1,1,3,3) = m;
|
||||
cout << "n = " << endl << n << endl << endl;
|
||||
|
||||
|
||||
n << 1,1,
|
||||
1,1;
|
||||
|
||||
// block as lvalue
|
||||
m.block(0,0,2,2) = n;
|
||||
|
||||
//print m
|
||||
cout << "m = " << endl << m << endl;
|
||||
Array33f res = n.block(0,0,3,3) * m;
|
||||
cout << "res =" << endl << res << endl;
|
||||
}
|
||||
|
@ -1,15 +1,14 @@
|
||||
#include <Eigen/Dense>
|
||||
#include <iostream>
|
||||
using namespace Eigen;
|
||||
|
||||
int main()
|
||||
{
|
||||
MatrixXf m(3,3);
|
||||
|
||||
Eigen::MatrixXf m(3,3);
|
||||
m << 1,2,3,
|
||||
4,5,6,
|
||||
7,8,9;
|
||||
|
||||
std::cout << "2nd Row: "
|
||||
<< m.row(1) << std::endl;
|
||||
std::cout << "2nd Row: " << m.row(1) << std::endl;
|
||||
m.col(0) += m.col(2);
|
||||
std::cout << "m after adding third column to first:\n";
|
||||
std::cout << m << std::endl;
|
||||
}
|
||||
|
@ -2,26 +2,16 @@
|
||||
#include <iostream>
|
||||
|
||||
using namespace std;
|
||||
using namespace Eigen;
|
||||
|
||||
int main()
|
||||
{
|
||||
MatrixXf m(4,4);
|
||||
|
||||
Eigen::Matrix4f m;
|
||||
m << 1, 2, 3, 4,
|
||||
5, 6, 7, 8,
|
||||
9, 10,11,12,
|
||||
13,14,15,16;
|
||||
|
||||
//print first two columns
|
||||
cout << "-- leftCols(2) --" << endl
|
||||
<< m.leftCols(2) << endl << endl;
|
||||
|
||||
//print last two rows
|
||||
cout << "-- bottomRows(2) --" << endl
|
||||
<< m.bottomRows(2) << endl << endl;
|
||||
|
||||
//print top-left 2x3 corner
|
||||
cout << "-- topLeftCorner(2,3) --" << endl
|
||||
<< m.topLeftCorner(2,3) << endl;
|
||||
cout << "m.leftCols(2) =" << endl << m.leftCols(2) << endl << endl;
|
||||
cout << "m.bottomRows<2>() =" << endl << m.bottomRows<2>() << endl << endl;
|
||||
m.topLeftCorner(1,3) = m.bottomRightCorner(3,1).transpose();
|
||||
cout << "After assignment, m = " << endl << m << endl;
|
||||
}
|
||||
|
@ -1,14 +1,18 @@
|
||||
#include <Eigen/Dense>
|
||||
#include <iostream>
|
||||
using namespace Eigen;
|
||||
|
||||
int main()
|
||||
{
|
||||
MatrixXf m(3,3);
|
||||
|
||||
m << 1,2,3,
|
||||
4,5,6,
|
||||
7,8,9;
|
||||
|
||||
std::cout << m.block(0,0,2,2) << std::endl;
|
||||
Eigen::MatrixXf m(4,4);
|
||||
m << 1, 2, 3, 4,
|
||||
5, 6, 7, 8,
|
||||
9,10,11,12,
|
||||
13,14,15,16;
|
||||
std::cout << "Block in the middle" << std::endl;
|
||||
std::cout << m.block<2,2>(1,1) << std::endl << std::endl;
|
||||
for (int i = 1; i < 4; ++i)
|
||||
{
|
||||
std::cout << "Block of size " << i << std::endl;
|
||||
std::cout << m.block(0,0,i,i) << std::endl << std::endl;
|
||||
}
|
||||
}
|
||||
|
@ -2,23 +2,13 @@
|
||||
#include <iostream>
|
||||
|
||||
using namespace std;
|
||||
using namespace Eigen;
|
||||
|
||||
int main()
|
||||
{
|
||||
VectorXf v(6);
|
||||
|
||||
Eigen::ArrayXf v(6);
|
||||
v << 1, 2, 3, 4, 5, 6;
|
||||
|
||||
//print first three elements
|
||||
cout << "-- head(3) --" << endl
|
||||
<< v.head(3) << endl << endl;
|
||||
|
||||
//print last three elements
|
||||
cout << "-- tail(3) --" << endl
|
||||
<< v.tail(3) << endl << endl;
|
||||
|
||||
//print between 2nd and 5th elem. inclusive
|
||||
cout << "-- segment(1,4) --" << endl
|
||||
<< v.segment(1,4) << endl;
|
||||
cout << "v.head(3) =" << endl << v.head(3) << endl << endl;
|
||||
cout << "v.tail<3>() = " << endl << v.tail<3>() << endl << endl;
|
||||
v.segment(1,4) *= 2;
|
||||
cout << "after 'v.segment(1,4) *= 2', v =" << endl << v << endl;
|
||||
}
|
||||
|
@ -282,7 +282,7 @@ namespace Eigen
|
||||
|
||||
namespace Eigen {
|
||||
|
||||
template<typename T> inline typename NumTraits<T>::Real test_precision() { return T(0); }
|
||||
template<typename T> inline typename NumTraits<T>::Real test_precision() { return NumTraits<T>::dummy_precision(); }
|
||||
template<> inline float test_precision<float>() { return 1e-3f; }
|
||||
template<> inline double test_precision<double>() { return 1e-6; }
|
||||
template<> inline float test_precision<std::complex<float> >() { return test_precision<float>(); }
|
||||
|
Loading…
x
Reference in New Issue
Block a user