diff options
author | 2008-08-12 07:49:59 +0000 | |
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committer | 2008-08-12 07:49:59 +0000 | |
commit | 8a3e6b1ee25b68460ebbb55115ef694f9f47011e (patch) | |
tree | 12646aa8823d4d8fb85e1b21280d24f62002ac56 /Eigen/src/Core/SolveTriangular.h | |
parent | 13ad88736e41cd22d057f67e39ba694be76f7010 (diff) |
change solveTriangularInPlace() to take a pointer as input (as discussed on IRC).
extended the documentation of the triangular solver.
Diffstat (limited to 'Eigen/src/Core/SolveTriangular.h')
-rwxr-xr-x | Eigen/src/Core/SolveTriangular.h | 54 |
1 files changed, 36 insertions, 18 deletions
diff --git a/Eigen/src/Core/SolveTriangular.h b/Eigen/src/Core/SolveTriangular.h index 5d6ee54eb..5f6cf7c28 100755 --- a/Eigen/src/Core/SolveTriangular.h +++ b/Eigen/src/Core/SolveTriangular.h @@ -37,21 +37,21 @@ template<typename Lhs, typename Rhs, : -1, int StorageOrder = int(Lhs::Flags) & RowMajorBit ? RowMajor : ColMajor > -struct ei_trisolve_selector; +struct ei_solve_triangular_selector; // transform a Part xpr to a Flagged xpr template<typename Lhs, unsigned int LhsMode, typename Rhs, int TriangularPart, int StorageOrder> -struct ei_trisolve_selector<Part<Lhs,LhsMode>,Rhs,TriangularPart,StorageOrder> +struct ei_solve_triangular_selector<Part<Lhs,LhsMode>,Rhs,TriangularPart,StorageOrder> { static void run(const Part<Lhs,LhsMode>& lhs, Rhs& other) { - ei_trisolve_selector<Flagged<Lhs,LhsMode,0>,Rhs>::run(lhs._expression(), other); + ei_solve_triangular_selector<Flagged<Lhs,LhsMode,0>,Rhs>::run(lhs._expression(), other); } }; // forward substitution, row-major template<typename Lhs, typename Rhs> -struct ei_trisolve_selector<Lhs,Rhs,Lower,RowMajor> +struct ei_solve_triangular_selector<Lhs,Rhs,Lower,RowMajor> { typedef typename Rhs::Scalar Scalar; static void run(const Lhs& lhs, Rhs& other) @@ -74,7 +74,7 @@ struct ei_trisolve_selector<Lhs,Rhs,Lower,RowMajor> // backward substitution, row-major template<typename Lhs, typename Rhs> -struct ei_trisolve_selector<Lhs,Rhs,Upper,RowMajor> +struct ei_solve_triangular_selector<Lhs,Rhs,Upper,RowMajor> { typedef typename Rhs::Scalar Scalar; static void run(const Lhs& lhs, Rhs& other) @@ -101,7 +101,7 @@ struct ei_trisolve_selector<Lhs,Rhs,Upper,RowMajor> // FIXME the Lower and Upper specialization could be merged using a small helper class // performing reflexions on the coordinates... template<typename Lhs, typename Rhs> -struct ei_trisolve_selector<Lhs,Rhs,Lower,ColMajor> +struct ei_solve_triangular_selector<Lhs,Rhs,Lower,ColMajor> { typedef typename Rhs::Scalar Scalar; typedef typename ei_packet_traits<Scalar>::type Packet; @@ -168,7 +168,7 @@ struct ei_trisolve_selector<Lhs,Rhs,Lower,ColMajor> // backward substitution, col-major // see the previous specialization for details on the algorithm template<typename Lhs, typename Rhs> -struct ei_trisolve_selector<Lhs,Rhs,Upper,ColMajor> +struct ei_solve_triangular_selector<Lhs,Rhs,Upper,ColMajor> { typedef typename Rhs::Scalar Scalar; static void run(const Lhs& lhs, Rhs& other) @@ -214,40 +214,58 @@ struct ei_trisolve_selector<Lhs,Rhs,Upper,ColMajor> /** "in-place" version of MatrixBase::solveTriangular() where the result is written in \a other * - * \sa solveTriangular() + * See MatrixBase:solveTriangular() for the details. */ template<typename Derived> template<typename OtherDerived> -void MatrixBase<Derived>::solveTriangularInPlace(MatrixBase<OtherDerived>& other) const +void MatrixBase<Derived>::solveTriangularInPlace(MatrixBase<OtherDerived>* p_other) const { + ei_assert(p_other!=0); ei_assert(derived().cols() == derived().rows()); - ei_assert(derived().cols() == other.rows()); + ei_assert(derived().cols() == p_other->rows()); ei_assert(!(Flags & ZeroDiagBit)); ei_assert(Flags & (UpperTriangularBit|LowerTriangularBit)); - ei_trisolve_selector<Derived, OtherDerived>::run(derived(), other.derived()); + ei_solve_triangular_selector<Derived, OtherDerived>::run(derived(), p_other->derived()); } /** \returns the product of the inverse of \c *this with \a other, \a *this being triangular. * - * This function computes the inverse-matrix matrix product inverse(\c *this) * \a other - * It works as a forward (resp. backward) substitution if \c *this is an upper (resp. lower) - * triangular matrix. + * This function computes the inverse-matrix matrix product inverse(\c *this) * \a other. + * The matrix \c *this must be triangular and invertible (i.e., all the coefficients of the + * diagonal must be non zero). It works as a forward (resp. backward) substitution if \c *this + * is an upper (resp. lower) triangular matrix. * - * It is required that \c *this be marked as either an upper or a lower triangular matrix, as - * can be done by marked(), and as is automatically the case with expressions such as those returned + * It is required that \c *this be marked as either an upper or a lower triangular matrix, which + * can be done by marked(), and that is automatically the case with expressions such as those returned * by extract(). + * + * \addexample SolveTriangular \label How to solve a triangular system (aka. how to multiply the inverse of a triangular matrix by another one) + * * Example: \include MatrixBase_marked.cpp * Output: \verbinclude MatrixBase_marked.out + * + * This function is essentially a wrapper to the faster solveTriangularInPlace() function creating + * a temporary copy of \a other, calling solveTriangularInPlace() on the copy and returning it. + * Therefore, if \a other is not needed anymore, it is quite faster to call solveTriangularInPlace() + * instead of solveTriangular(). + * + * For users comming from BLAS, this function (and more specifically solveTriangularInPlace()) offer + * all the operations supported by the \c *TRSV and \c *TRSM BLAS routines. * - * \sa marked(), extract() + * \b Tips: to perform a \em "right-inverse-multiply" you can simply transpose the operation, e.g.: + * \code + * M * T^1 <=> T.transpose().solveTriangularInPlace(M.transpose()); + * \endcode + * + * \sa solveTriangularInPlace(), marked(), extract() */ template<typename Derived> template<typename OtherDerived> typename OtherDerived::Eval MatrixBase<Derived>::solveTriangular(const MatrixBase<OtherDerived>& other) const { typename OtherDerived::Eval res(other); - solveTriangularInPlace(res); + solveTriangularInPlace(&res); return res; } |