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document lazyProduct

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This commit is contained in:
Gael Guennebaud 2010-02-09 14:45:17 +01:00
parent 840977529f
commit 285bc336d5
1 changed files with 17 additions and 2 deletions
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19
Eigen/src/Core/Product.h
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@ -420,7 +420,7 @@ template<> struct ei_gemv_selector<OnTheRight,RowMajor,false>
*
* \note If instead of the matrix product you want the coefficient-wise product, see Cwise::operator*().
*
* \sa lazy(), operator*=(const MatrixBase&), Cwise::operator*()
* \sa lazyProduct(), operator*=(const MatrixBase&), Cwise::operator*()
*/
template<typename Derived>
template<typename OtherDerived>
@ -445,7 +445,22 @@ MatrixBase<Derived>::operator*(const MatrixBase<OtherDerived> &other) const
return typename ProductReturnType<Derived,OtherDerived>::Type(derived(), other.derived());
}
/** \returns an expression of the matrix product of \c *this and \a other without implicit evaluation.
*
* The coefficients of the product will be computed as requested that is particularly useful when you
* only want to compute a small fraction of the result's coefficients.
* Here is an example:
* \code
* MatrixXf a(10,10), b(10,10);
* (a*b).diagonal().sum(); // here a*b is entirely computed into a 10x10 temporary matrix
* a.lazyProduct(b).diagonal().sum(); // here a*b is evaluated in a lazy manner,
* // so only the diagonal coefficients will be computed
* \endcode
*
* \warning This version of the matrix product can be much much slower if all coefficients have to be computed anyways.
*
* \sa operator*(const MatrixBase&)
*/
template<typename Derived>
template<typename OtherDerived>
const typename ProductReturnType<Derived,OtherDerived,LazyCoeffBasedProductMode>::Type