[PPL-devel] [GIT] ppl/ppl(floating_point): Added a skeleton for the new linearization function.

[Fabio Bossi]

Module: ppl/ppl
Branch: floating_point
Commit: 1c4c91c248d74dc5abb8c5b45507dfe9665ff6b5
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=1c4c91c248d74dc5abb8c5b45507dfe9665ff6b5

Author: Fabio Bossi <bossi at cs.unipr.it>
Date:   Sat Jul 24 12:39:51 2010 +0200

Added a skeleton for the new linearization function.

Also added an idea for the linearization of the
unary negation expression.

---

 src/linearize.hh |  160 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 160 insertions(+), 0 deletions(-)

diff --git a/src/linearize.hh b/src/linearize.hh
new file mode 100644
index 0000000..6a39f03
--- /dev/null
+++ b/src/linearize.hh
@@ -0,0 +1,160 @@
+1/* Linearization function implementation.
+   Copyright (C) 2001-2010 Roberto Bagnara <bagnara at cs.unipr.it>
+
+This file is part of the Parma Polyhedra Library (PPL).
+
+The PPL is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The PPL is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software Foundation,
+Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1307, USA.
+
+For the most up-to-date information see the Parma Polyhedra Library
+site: http://www.cs.unipr.it/ppl/ . */
+
+#ifndef PPL_linearize_hh
+#define PPL_linearize_hh 1
+
+#include "Concrete_Expression.defs.hh"
+#include "Float.defs.hh"
+#include "Linear_Form.defs.hh"
+#include "Box.defs.hh"
+#include <map>
+
+namespace Parma_Polyhedra_Library {
+
+template <typename Target, typename FP_Interval_Type>
+static bool
+bnot_linearize(const Unary_Operator<Target>& uop_expr,
+               const Box<FP_Interval_Type>& int_store,
+               const std::map<dimension_type, Linear_Form<FP_Interval_Type>>& lf_store,
+               Linear_Form<FP_Interval_Type>& result) {
+  typedef typename FP_Interval_Type::boundary_type analyzer_format;
+  typedef Linear_Form<FP_Interval_Type> FP_Linear_Form;
+  typedef Box<FP_Interval_Type> FP_Interval_Abstract_Store;
+  typedef std::map<dimension_type, FP_Linear_Form> FP_Linear_Form_Abstract_Store;
+
+  if (!linearize(uop_expr.get_arg(), int_store, lf_store, result))
+    return false;
+
+  FP_Interval_Type int_r;
+  result.intervalize(int_store, int_r);
+  bool lb_is_positive = (!int_r.is_lower_boundary_infinity() &&
+                         int_r.lower() > 0);
+  bool ub_is_negative = (!int_r.is_upper_boundary_infinity() &&
+                         int_r.upper() < 0);
+  if (lb_is_positive || ub_is_negative) {
+    result = FP_Linear_Form(FP_Interval(0));
+    return true;
+  }
+  else if (int_r.is_singleton()) {
+    // Here int_r is the singleton of 0.
+    // FIXME: Check if the negation of 0 MUST be 1.
+    result = FP_Linear_Form(FP_Interval(1));
+    return true;
+  }
+  else
+    // Here int_r strictly contains 0.
+    return false;
+}
+
+template <typename Target, typename FP_Interval_Type>
+bool
+linearize(const Concrete_Expression<Target>& expr,
+          const Box<FP_Interval_Type>& int_store,
+          const std::map<dimension_type, Linear_Form<FP_Interval_Type>>& lf_store,
+          Linear_Form<FP_Interval_Type>& result) {
+  typedef typename FP_Interval_Type::boundary_type analyzer_format;
+  typedef Linear_Form<FP_Interval_Type> FP_Linear_Form;
+  typedef Box<FP_Interval_Type> FP_Interval_Abstract_Store;
+  typedef std::map<dimension_type, FP_Linear_Form> FP_Linear_Form_Abstract_Store;
+
+  // Check that analyzer_format is a floating point type.
+  PPL_COMPILE_TIME_CHECK(!std::numeric_limits<analyzer_format>::is_exact,
+      "linearize<Target, FP_Interval_Type>:"
+      " FP_Interval_Type is not the type of an interval with floating point boundaries.");
+
+  // Check that we are dealing with an expression of floating point type.
+  PPL_ASSERT(expr.is_floating_point());
+
+  /*
+  Floating_Point_Format analyzed_format = expr.floating_point_format();
+  FP_Interval_Type absolute_error =
+                   compute_absolute_error<FP_Interval_Type>(analyzed_format);
+  */
+  switch(expr.kind()) {
+  case INT_CON:
+    // TODO.
+    break;
+  case FP_CON:
+    Floating_Point_Constant<Target> fpc_expr =
+      static_cast<Floating_Point_Constant<Target>>(expr);
+    result = FP_Linear_Form(FP_Interval(fpc_expr.get_value_as_string()));
+    return true;
+    break;
+  case UOP:
+    Unary_Operator<Target> uop_expr =
+      static_cast<Unary_Operator<Target>>(expr);
+    switch (uop_expr.get_uop()) {
+    case PLUS:
+      return linearize(uop_expr.get_arg(), int_store, lf_store, result);
+      break;
+    case MINUS:
+      if (!linearize(uop_expr.get_arg(), int_store, lf_store, result))
+        return false;
+
+      result.negate();
+      return true;
+      break;
+    case BNOT:
+      return bnot_linearize(uop_expr, int_store, lf_store, result);
+      break;
+    default:
+      throw std::runtime_error("PPL internal error");
+    }
+    break;
+  case BOP:
+    Binary_Operator<Target> bop_expr =
+      static_cast<Binary_Operator<Target>>(expr);
+    switch (bop_expr.get_bop()) {
+    case ADD:
+      return add_linearize(bop_expr, int_store, lf_store, result);
+      break;
+    case SUB:
+      return sub_linearize(bop_expr, int_store, lf_store, result);
+      break;
+    case MUL:
+      return mul_linearize(bop_expr, int_store, lf_store, result);
+      break;
+    case DIV:
+      return div_linearize(bop_expr, int_store, lf_store, result);
+      break;
+    case REM:
+    case BAND:
+    case BOR:
+    case BXOR:
+    case LSHIFT:
+    case RSHIFT:
+    default:
+      throw std::runtime_error("PPL internal error");
+    }
+    break;
+  case CAST:
+    // TODO.
+    break;
+  default:
+    throw std::runtime_error("PPL internal error");
+  }
+}
+
+} // namespace Parma_Polyhedra_Library
+
+#endif // !defined(PPL_linearize_hh)