[PPL-devel] [GIT] ppl/ppl(products): Added new method frequency() for Grids.

[Patricia Hill]

Module: ppl/ppl
Branch: products
Commit: c7f4b16d84c83be74fb0e62080e2d22b51d170a6
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=c7f4b16d84c83be74fb0e62080e2d22b51d170a6

Author: Patricia Hill <p.m.hill at leeds.ac.uk>
Date:   Thu May 14 07:41:22 2009 +0100

Added new method frequency() for Grids.

---

 src/Grid.defs.hh       |   33 +++++++++++++++++++++++++++++++++
 src/Grid_public.cc     |   26 ++++++++++++++++++++++++++
 tests/Grid/Makefile.am |    3 +++
 3 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/src/Grid.defs.hh b/src/Grid.defs.hh
index 3049c31..0ad5277 100644
--- a/src/Grid.defs.hh
+++ b/src/Grid.defs.hh
@@ -861,6 +861,39 @@ public:
 		Coefficient& inf_n, Coefficient& inf_d, bool& minimum,
 		Generator& point) 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.
+
+    \param expr
+    The linear expression for which the frequency is needed;
+
+    \param freq_n
+    The numerator of the maximum frequency of \p expr;
+
+    \param freq_d
+    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
+    that is closest to zero;
+
+    \param val_d
+    The denominator of a value of \p expr at a point in the grid
+    that is closest to zero;
+
+    \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,
+    \p val_n and \p val_d are left untouched.
+  */
+  bool frequency(const Linear_Expression& expr,
+                 Coefficient& freq_n, Coefficient& freq_d,
+                 Coefficient& val_n, Coefficient& val_d) const;
+
   //! Returns <CODE>true</CODE> if and only if \p *this contains \p y.
   /*!
     \exception std::invalid_argument
diff --git a/src/Grid_public.cc b/src/Grid_public.cc
index 16e6ba9..24a53f6 100644
--- a/src/Grid_public.cc
+++ b/src/Grid_public.cc
@@ -2475,6 +2475,32 @@ PPL::Grid::time_elapse_assign(const Grid& y) {
   assert(x.OK(true) && y.OK(true));
 }
 
+bool
+PPL::Grid::frequency(const Linear_Expression& expr,
+                     Coefficient& freq_n, Coefficient& freq_d,
+                     Coefficient& val_n, Coefficient& val_d) const {
+  // The dimension of `expr' must be at most the dimension of *this.
+  if (space_dim < expr.space_dimension())
+    throw_dimension_incompatible("frequency(e, ...)", "e", expr);
+
+  // Space dimension = 0: if empty, then return false;
+  // otherwise the frequency is 1 and the value is 0
+  if (space_dim == 0) {
+    if (is_empty())
+      return false;
+    freq_n = 0;
+    freq_d = 1;
+    val_n = 0;
+    val_d = 1;
+    return true;
+  }
+  if (!generators_are_minimized() && !minimize())
+    // Minimizing found `this' empty.
+    return false;
+
+  return frequency_no_check(expr, freq_n, freq_d, val_n, val_d);
+}
+
 /*! \relates Parma_Polyhedra_Library::Grid */
 bool
 PPL::operator==(const Grid& x, const Grid& y) {
diff --git a/tests/Grid/Makefile.am b/tests/Grid/Makefile.am
index 7189082..74bab01 100644
--- a/tests/Grid/Makefile.am
+++ b/tests/Grid/Makefile.am
@@ -81,6 +81,7 @@ disjoint1 \
 equals1 \
 expandspacedim1 \
 foldspacedims1 \
+frequency1 \
 frombdshape1 \
 frombox1 \
 fromgrid1 \
@@ -191,6 +192,8 @@ equals1_SOURCES = equals1.cc
 
 expandspacedim1_SOURCES = expandspacedim1.cc
 
+frequency1_SOURCES = frequency1.cc
+
 frombdshape1_SOURCES = frombdshape1.cc
 
 frombox1_SOURCES = frombox1.cc