Module: ppl/ppl Branch: master Commit: 4c45d375b4eced85f65931946464d71f9041cc29 URL: http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=4c45d375b4ece... Author: Patricia Hill <p.m.hill@leeds.ac.uk> Date: Fri Mar 19 08:53:12 2010 +0000 Improved documentation for frequency(). --- src/Grid.defs.hh | 12 +++++++++--- src/Polyhedron.defs.hh | 15 ++++++++++----- 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/src/Grid.defs.hh b/src/Grid.defs.hh index 59e840f..32d671b 100644 --- a/src/Grid.defs.hh +++ b/src/Grid.defs.hh @@ -863,8 +863,14 @@ public: /*! \brief Returns <CODE>true</CODE> if and only if \p *this is not empty and - \p expr is discrete in \p *this, in which case the maximum frequency - and the value for \p expr that is closest to zero are computed. + \p expr intersects with \p *this and \p *this is discrete on the hyperplane + defined by \p expr, in which case the frequency of \p *this + and the infimum value for \p expr for a point in \p *this are computed. + + If <CODE>true</CODE> is returned then the frequency of a grid \f$\cP\f$ + with respect to a linear expression \f$e\f$ is the modulus + \f$m\f$ such that all the points of the grid \f$\cP\f$ satisfy + the congruence \f$e \%= c \pmod{m}\f$ for some value \f$c\f$. \param expr The linear expression for which the frequency is needed; @@ -876,7 +882,7 @@ public: The denominator of the maximum frequency of \p expr; \param val_n - The numerator of a value of \p expr at a point in the grid + The numerator of them value of \p expr at a point in the grid that is closest to zero; \param val_d diff --git a/src/Polyhedron.defs.hh b/src/Polyhedron.defs.hh index 52f6bb2..e4c54b2 100644 --- a/src/Polyhedron.defs.hh +++ b/src/Polyhedron.defs.hh @@ -765,9 +765,10 @@ public: Generator& g) const; /*! \brief - Returns <CODE>true</CODE> if and only if \p *this is not empty and - \p expr is discrete in \p *this, in which case the maximum frequency - and the value for \p expr that is closest to zero are computed. + Returns <CODE>true</CODE> if and only if \p *this intersects with + the hyperplane defined by \p expr at a single point; in which case + the frequency of \p *this and the infimum value for \p expr for a + point in \p *this are computed. \param expr The linear expression for which the frequency is needed; @@ -789,9 +790,13 @@ public: \exception std::invalid_argument Thrown if \p expr and \p *this are dimension-incompatible. - If \p *this is empty or \p expr can take any real number in \p *this, - <CODE>false</CODE> is returned and \p freq_n, \p freq_d, + If \p expr has no value in \p *this or can take more than one value + in \p *this, <CODE>false</CODE> is returned and \p freq_n, \p freq_d, \p val_n and \p val_d are left untouched. + If \p expr has a unique value in \p *this, then + the frequency of a polyhedron \f$\cP\f$ with respect to a linear expression + \f$e\f$ is \f$0\f$ and the value is given by \p val_n and \p val_d. + */ bool frequency(const Linear_Expression& expr, Coefficient& freq_n, Coefficient& freq_d,