Add minimum-distance constraints with single and decomposed propagation

Makefile.dep

@@ -35114,3 +35114,132 @@ test/flatzinc/on_restart_sol_set$(OBJSUFFIX) test/flatzinc/on_restart_sol_set$(S
 	./gecode/support/static-stack.hpp ./gecode/support/thread.hpp ./gecode/support/thread/thread.hpp \
 	./gecode/support/timer.hpp ./test/flatzinc.hh ./test/test.hh \
 	./test/test.hpp
+gecode/int/min-distance$(OBJSUFFIX) gecode/int/min-distance$(SBJSUFFIX): \
+	./gecode/int.hh ./gecode/int/array-traits.hpp ./gecode/int/array.hpp \
+	./gecode/int/branch.hpp ./gecode/int/branch/action.hpp ./gecode/int/branch/afc.hpp \
+	./gecode/int/branch/assign.hpp ./gecode/int/branch/chb.hpp ./gecode/int/branch/traits.hpp \
+	./gecode/int/branch/val.hpp ./gecode/int/branch/var.hpp ./gecode/int/channel.hpp \
+	./gecode/int/div.hh ./gecode/int/div.hpp ./gecode/int/exception.hpp \
+	./gecode/int/extensional.hpp ./gecode/int/extensional/dfa.hpp ./gecode/int/extensional/tuple-set.hpp \
+	./gecode/int/int-set-1.hpp ./gecode/int/int-set-2.hpp ./gecode/int/ipl.hpp \
+	./gecode/int/irt.hpp ./gecode/int/limits.hpp ./gecode/int/min-distance.hpp \
+	./gecode/int/propagator.hpp ./gecode/int/reify.hpp ./gecode/int/trace.hpp \
+	./gecode/int/trace/bool-delta.hpp ./gecode/int/trace/bool-trace-view.hpp ./gecode/int/trace/int-delta.hpp \
+	./gecode/int/trace/int-trace-view.hpp ./gecode/int/trace/traits.hpp ./gecode/int/var-imp.hpp \
+	./gecode/int/var-imp/bool.hpp ./gecode/int/var-imp/delta.hpp ./gecode/int/var-imp/int.hpp \
+	./gecode/int/var/bool.hpp ./gecode/int/var/int.hpp ./gecode/int/var/print.hpp \
+	./gecode/int/view.hpp ./gecode/int/view/bool-test.hpp ./gecode/int/view/bool.hpp \
+	./gecode/int/view/cached.hpp ./gecode/int/view/constint.hpp ./gecode/int/view/int.hpp \
+	./gecode/int/view/iter.hpp ./gecode/int/view/minus.hpp ./gecode/int/view/neg-bool.hpp \
+	./gecode/int/view/offset.hpp ./gecode/int/view/print.hpp ./gecode/int/view/rel-test.hpp \
+	./gecode/int/view/scale.hpp ./gecode/int/view/zero.hpp ./gecode/iter.hh \
+	./gecode/iter/ranges-add.hpp ./gecode/iter/ranges-append.hpp ./gecode/iter/ranges-array.hpp \
+	./gecode/iter/ranges-cache.hpp ./gecode/iter/ranges-compl.hpp ./gecode/iter/ranges-diff.hpp \
+	./gecode/iter/ranges-empty.hpp ./gecode/iter/ranges-inter.hpp ./gecode/iter/ranges-list.hpp \
+	./gecode/iter/ranges-map.hpp ./gecode/iter/ranges-minmax.hpp ./gecode/iter/ranges-minus.hpp \
+	./gecode/iter/ranges-negative.hpp ./gecode/iter/ranges-offset.hpp ./gecode/iter/ranges-operations.hpp \
+	./gecode/iter/ranges-positive.hpp ./gecode/iter/ranges-rangelist.hpp ./gecode/iter/ranges-scale.hpp \
+	./gecode/iter/ranges-singleton-append.hpp ./gecode/iter/ranges-singleton.hpp ./gecode/iter/ranges-size.hpp \
+	./gecode/iter/ranges-union.hpp ./gecode/iter/ranges-values.hpp ./gecode/iter/values-array.hpp \
+	./gecode/iter/values-bitset.hpp ./gecode/iter/values-bitsetoffset.hpp ./gecode/iter/values-inter.hpp \
+	./gecode/iter/values-list.hpp ./gecode/iter/values-map.hpp ./gecode/iter/values-minus.hpp \
+	./gecode/iter/values-negative.hpp ./gecode/iter/values-offset.hpp ./gecode/iter/values-positive.hpp \
+	./gecode/iter/values-ranges.hpp ./gecode/iter/values-singleton.hpp ./gecode/iter/values-union.hpp \
+	./gecode/iter/values-unique.hpp ./gecode/kernel.hh ./gecode/kernel/archive.hpp \
+	./gecode/kernel/branch/action.hpp ./gecode/kernel/branch/afc.hpp ./gecode/kernel/branch/chb.hpp \
+	./gecode/kernel/branch/filter.hpp ./gecode/kernel/branch/merit.hpp ./gecode/kernel/branch/print.hpp \
+	./gecode/kernel/branch/tiebreak.hpp ./gecode/kernel/branch/traits.hpp ./gecode/kernel/branch/val-commit.hpp \
+	./gecode/kernel/branch/val-sel-commit.hpp ./gecode/kernel/branch/val-sel.hpp ./gecode/kernel/branch/val.hpp \
+	./gecode/kernel/branch/var.hpp ./gecode/kernel/branch/view-sel.hpp ./gecode/kernel/branch/view-val.hpp \
+	./gecode/kernel/branch/view.hpp ./gecode/kernel/core.hpp ./gecode/kernel/data/array.hpp \
+	./gecode/kernel/data/rnd.hpp ./gecode/kernel/data/shared-array.hpp ./gecode/kernel/data/shared-data.hpp \
+	./gecode/kernel/exception.hpp ./gecode/kernel/gpi.hpp ./gecode/kernel/macros.hpp \
+	./gecode/kernel/memory/allocators.hpp ./gecode/kernel/memory/config.hpp ./gecode/kernel/memory/manager.hpp \
+	./gecode/kernel/memory/region.hpp ./gecode/kernel/modevent.hpp ./gecode/kernel/propagator/advisor.hpp \
+	./gecode/kernel/propagator/pattern.hpp ./gecode/kernel/propagator/subscribed.hpp ./gecode/kernel/propagator/wait.hpp \
+	./gecode/kernel/range-list.hpp ./gecode/kernel/shared-object.hpp ./gecode/kernel/shared-space-data.hpp \
+	./gecode/kernel/trace/filter.hpp ./gecode/kernel/trace/general.hpp ./gecode/kernel/trace/print.hpp \
+	./gecode/kernel/trace/recorder.hpp ./gecode/kernel/trace/tracer.hpp ./gecode/kernel/trace/traits.hpp \
+	./gecode/kernel/var-imp.hpp ./gecode/kernel/var-type.hpp ./gecode/kernel/var.hpp \
+	./gecode/kernel/view.hpp ./gecode/search.hh ./gecode/search/bab.hpp \
+	./gecode/search/base.hpp ./gecode/search/build.hpp ./gecode/search/cutoff.hpp \
+	./gecode/search/dfs.hpp ./gecode/search/engine.hpp ./gecode/search/exception.hpp \
+	./gecode/search/lds.hpp ./gecode/search/options.hpp ./gecode/search/pbs.hpp \
+	./gecode/search/rbs.hpp ./gecode/search/sebs.hpp ./gecode/search/seq/dead.hh \
+	./gecode/search/statistics.hpp ./gecode/search/stop.hpp ./gecode/search/support.hh \
+	./gecode/search/trace-recorder.hpp ./gecode/search/tracer.hpp ./gecode/search/traits.hpp \
+	./gecode/support.hh ./gecode/support/allocator.hpp ./gecode/support/auto-link.hpp \
+	./gecode/support/bitset-base.hpp ./gecode/support/bitset-offset.hpp ./gecode/support/bitset.hpp \
+	./gecode/support/block-allocator.hpp ./gecode/support/cast.hpp gecode/support/config.hpp \
+	./gecode/support/dynamic-array.hpp ./gecode/support/dynamic-queue.hpp ./gecode/support/dynamic-stack.hpp \
+	./gecode/support/exception.hpp ./gecode/support/failpoint.hpp ./gecode/support/hash.hpp \
+	./gecode/support/heap.hpp ./gecode/support/hw-rnd.hpp ./gecode/support/int-type.hpp \
+	./gecode/support/macros.hpp ./gecode/support/marked-pointer.hpp ./gecode/support/random.hpp \
+	./gecode/support/ref-count.hpp ./gecode/support/run-jobs.hpp ./gecode/support/sort.hpp \
+	./gecode/support/static-stack.hpp ./gecode/support/thread.hpp ./gecode/support/thread/thread.hpp \
+	./gecode/support/timer.hpp
+test/int/min-distance$(OBJSUFFIX) test/int/min-distance$(SBJSUFFIX): \
+	./gecode/int.hh ./gecode/int/array-traits.hpp ./gecode/int/array.hpp \
+	./gecode/int/branch.hpp ./gecode/int/branch/action.hpp ./gecode/int/branch/afc.hpp \
+	./gecode/int/branch/assign.hpp ./gecode/int/branch/chb.hpp ./gecode/int/branch/traits.hpp \
+	./gecode/int/branch/val.hpp ./gecode/int/branch/var.hpp ./gecode/int/channel.hpp \
+	./gecode/int/div.hh ./gecode/int/div.hpp ./gecode/int/exception.hpp \
+	./gecode/int/extensional.hpp ./gecode/int/extensional/dfa.hpp ./gecode/int/extensional/tuple-set.hpp \
+	./gecode/int/int-set-1.hpp ./gecode/int/int-set-2.hpp ./gecode/int/ipl.hpp \
+	./gecode/int/irt.hpp ./gecode/int/limits.hpp ./gecode/int/min-distance.hpp \
+	./gecode/int/propagator.hpp ./gecode/int/reify.hpp ./gecode/int/trace.hpp \
+	./gecode/int/trace/bool-delta.hpp ./gecode/int/trace/bool-trace-view.hpp ./gecode/int/trace/int-delta.hpp \
+	./gecode/int/trace/int-trace-view.hpp ./gecode/int/trace/traits.hpp ./gecode/int/var-imp.hpp \
+	./gecode/int/var-imp/bool.hpp ./gecode/int/var-imp/delta.hpp ./gecode/int/var-imp/int.hpp \
+	./gecode/int/var/bool.hpp ./gecode/int/var/int.hpp ./gecode/int/var/print.hpp \
+	./gecode/int/view.hpp ./gecode/int/view/bool-test.hpp ./gecode/int/view/bool.hpp \
+	./gecode/int/view/cached.hpp ./gecode/int/view/constint.hpp ./gecode/int/view/int.hpp \
+	./gecode/int/view/iter.hpp ./gecode/int/view/minus.hpp ./gecode/int/view/neg-bool.hpp \
+	./gecode/int/view/offset.hpp ./gecode/int/view/print.hpp ./gecode/int/view/rel-test.hpp \
+	./gecode/int/view/scale.hpp ./gecode/int/view/zero.hpp ./gecode/iter.hh \
+	./gecode/iter/ranges-add.hpp ./gecode/iter/ranges-append.hpp ./gecode/iter/ranges-array.hpp \
+	./gecode/iter/ranges-cache.hpp ./gecode/iter/ranges-compl.hpp ./gecode/iter/ranges-diff.hpp \
+	./gecode/iter/ranges-empty.hpp ./gecode/iter/ranges-inter.hpp ./gecode/iter/ranges-list.hpp \
+	./gecode/iter/ranges-map.hpp ./gecode/iter/ranges-minmax.hpp ./gecode/iter/ranges-minus.hpp \
+	./gecode/iter/ranges-negative.hpp ./gecode/iter/ranges-offset.hpp ./gecode/iter/ranges-operations.hpp \
+	./gecode/iter/ranges-positive.hpp ./gecode/iter/ranges-rangelist.hpp ./gecode/iter/ranges-scale.hpp \
+	./gecode/iter/ranges-singleton-append.hpp ./gecode/iter/ranges-singleton.hpp ./gecode/iter/ranges-size.hpp \
+	./gecode/iter/ranges-union.hpp ./gecode/iter/ranges-values.hpp ./gecode/iter/values-array.hpp \
+	./gecode/iter/values-bitset.hpp ./gecode/iter/values-bitsetoffset.hpp ./gecode/iter/values-inter.hpp \
+	./gecode/iter/values-list.hpp ./gecode/iter/values-map.hpp ./gecode/iter/values-minus.hpp \
+	./gecode/iter/values-negative.hpp ./gecode/iter/values-offset.hpp ./gecode/iter/values-positive.hpp \
+	./gecode/iter/values-ranges.hpp ./gecode/iter/values-singleton.hpp ./gecode/iter/values-union.hpp \
+	./gecode/iter/values-unique.hpp ./gecode/kernel.hh ./gecode/kernel/archive.hpp \
+	./gecode/kernel/branch/action.hpp ./gecode/kernel/branch/afc.hpp ./gecode/kernel/branch/chb.hpp \
+	./gecode/kernel/branch/filter.hpp ./gecode/kernel/branch/merit.hpp ./gecode/kernel/branch/print.hpp \
+	./gecode/kernel/branch/tiebreak.hpp ./gecode/kernel/branch/traits.hpp ./gecode/kernel/branch/val-commit.hpp \
+	./gecode/kernel/branch/val-sel-commit.hpp ./gecode/kernel/branch/val-sel.hpp ./gecode/kernel/branch/val.hpp \
+	./gecode/kernel/branch/var.hpp ./gecode/kernel/branch/view-sel.hpp ./gecode/kernel/branch/view-val.hpp \
+	./gecode/kernel/branch/view.hpp ./gecode/kernel/core.hpp ./gecode/kernel/data/array.hpp \
+	./gecode/kernel/data/rnd.hpp ./gecode/kernel/data/shared-array.hpp ./gecode/kernel/data/shared-data.hpp \
+	./gecode/kernel/exception.hpp ./gecode/kernel/gpi.hpp ./gecode/kernel/macros.hpp \
+	./gecode/kernel/memory/allocators.hpp ./gecode/kernel/memory/config.hpp ./gecode/kernel/memory/manager.hpp \
+	./gecode/kernel/memory/region.hpp ./gecode/kernel/modevent.hpp ./gecode/kernel/propagator/advisor.hpp \
+	./gecode/kernel/propagator/pattern.hpp ./gecode/kernel/propagator/subscribed.hpp ./gecode/kernel/propagator/wait.hpp \
+	./gecode/kernel/range-list.hpp ./gecode/kernel/shared-object.hpp ./gecode/kernel/shared-space-data.hpp \
+	./gecode/kernel/trace/filter.hpp ./gecode/kernel/trace/general.hpp ./gecode/kernel/trace/print.hpp \
+	./gecode/kernel/trace/recorder.hpp ./gecode/kernel/trace/tracer.hpp ./gecode/kernel/trace/traits.hpp \
+	./gecode/kernel/var-imp.hpp ./gecode/kernel/var-type.hpp ./gecode/kernel/var.hpp \
+	./gecode/kernel/view.hpp ./gecode/search.hh ./gecode/search/bab.hpp \
+	./gecode/search/base.hpp ./gecode/search/build.hpp ./gecode/search/cutoff.hpp \
+	./gecode/search/dfs.hpp ./gecode/search/engine.hpp ./gecode/search/exception.hpp \
+	./gecode/search/lds.hpp ./gecode/search/options.hpp ./gecode/search/pbs.hpp \
+	./gecode/search/rbs.hpp ./gecode/search/sebs.hpp ./gecode/search/seq/dead.hh \
+	./gecode/search/statistics.hpp ./gecode/search/stop.hpp ./gecode/search/support.hh \
+	./gecode/search/trace-recorder.hpp ./gecode/search/tracer.hpp ./gecode/search/traits.hpp \
+	./gecode/support.hh ./gecode/support/allocator.hpp ./gecode/support/auto-link.hpp \
+	./gecode/support/bitset-base.hpp ./gecode/support/bitset-offset.hpp ./gecode/support/bitset.hpp \
+	./gecode/support/block-allocator.hpp ./gecode/support/cast.hpp gecode/support/config.hpp \
+	./gecode/support/dynamic-array.hpp ./gecode/support/dynamic-queue.hpp ./gecode/support/dynamic-stack.hpp \
+	./gecode/support/exception.hpp ./gecode/support/failpoint.hpp ./gecode/support/hash.hpp \
+	./gecode/support/heap.hpp ./gecode/support/hw-rnd.hpp ./gecode/support/int-type.hpp \
+	./gecode/support/macros.hpp ./gecode/support/marked-pointer.hpp ./gecode/support/random.hpp \
+	./gecode/support/ref-count.hpp ./gecode/support/run-jobs.hpp ./gecode/support/sort.hpp \
+	./gecode/support/static-stack.hpp ./gecode/support/thread.hpp ./gecode/support/thread/thread.hpp \
+	./gecode/support/timer.hpp ./test/int.hh ./test/int.hpp \
+	./test/test.hh ./test/test.hpp

Makefile.in

@@ -338,7 +338,7 @@ INTSRC0 = \
 	order.cpp order/propagate.cpp \
 	unary.cpp cumulative.cpp cumulatives.cpp \
 	circuit.cpp no-overlap.cpp nvalues.cpp \
-	member.cpp branch/action.cpp branch/chb.cpp \
+	member.cpp min-distance.cpp branch/action.cpp branch/chb.cpp \
 	arithmetic/mult.cpp  \
 	branch/view-sel.cpp branch/val-sel-commit.cpp \
 	branch/view-values.cpp \
@@ -398,7 +398,7 @@ INTHDR0 = \
 	view/offset.hpp view/rel-test.hpp view/scale.hpp view/iter.hpp \
 	arithmetic.hh array.hpp array-traits.hpp bool.hh branch.hh \
 	distinct.hh dom.hh \
-	element.hh exception.hpp  gcc.hh linear.hh \
+	element.hh min-distance.hpp exception.hpp  gcc.hh linear.hh \
 	reify.hpp propagator.hpp extensional.hh rel.hh \
 	sorted.hh var-imp.hpp view.hpp ipl.hpp irt.hpp \
 	channel.hh channel.hpp channel/dom.hpp channel/val.hpp \
@@ -1121,7 +1121,7 @@ INTTESTSRC00 = \
 	rel linear gcc sorted unshare exec sequence \
 	mm-arithmetic mm-bool mm-lin mm-count mm-rel \
 	bin-packing order unary cumulative cumulatives circuit \
-	no-overlap precede nvalues member
+	no-overlap precede nvalues member min-distance
 INTTESTSRC0 = test/int.cpp $(INTTESTSRC00:%=test/int/%.cpp)
 INTTESTOBJ = $(INTTESTSRC0:%.cpp=%$(OBJSUFFIX))
 

changelog.in

@@ -149,6 +149,19 @@ to register and run Gecode-style tests for every configured variable family.
 Support shared and static harness libraries using the configured Gecode
 library variants. Add exact replay of a failed test iteration with `-replay`.
 
+[ENTRY]
+Module: int
+What:   new
+Rank:   major
+[DESCRIPTION]
+Add exact minimum-distance constraints over indexed sites, with decomposed
+and single-propagator forward-bound propagation, optional conflict-matching
+upper bounds, and inclusive requirements for selected-position pairs.
+Distances can use a shared matrix or a shared callable evaluated on demand.
+The propagation algorithms follow:
+M. Z. Lagerkvist, Propagation Algorithms for the Minimum-Distance Constraint
+over Selected Points, ModRef 2026.
+
 [RELEASE]
 Version: 6.4.0
 Date: 2026-07-15

cmake/GecodeSources.cmake

@@ -96,6 +96,7 @@ set(GECODE_INT_SOURCES
   gecode/int/linear/bool-post.cpp
   gecode/int/linear/int-post.cpp
   gecode/int/member.cpp
+  gecode/int/min-distance.cpp
   gecode/int/no-overlap.cpp
   gecode/int/nvalues.cpp
   gecode/int/order.cpp
@@ -416,6 +417,7 @@ set(GECODE_TEST_SOURCES
   test/int/gcc.cpp
   test/int/linear.cpp
   test/int/member.cpp
+  test/int/min-distance.cpp
   test/int/mm-arithmetic.cpp
   test/int/mm-bool.cpp
   test/int/mm-count.cpp

gecode/int.hh

@@ -2898,6 +2898,122 @@ namespace Gecode {
 
 #include <gecode/int/extensional.hpp>
 
+namespace Gecode {
+
+
+  /**
+   * \defgroup TaskModelIntMinDistance Minimum distance constraints
+   * \ingroup TaskModelInt
+   */
+  //@{
+  /** \brief Shared distances between indexed sites
+   *
+   * Distances are nonnegative, symmetric, and zero on the diagonal.
+   * No triangle inequality is required. Site indices range from zero to
+   * size()-1. Matrix entries or a callable are shared across propagators,
+   * clones, and search threads.
+   */
+  class IntDistance : public SharedHandle {
+  protected:
+    /// Shared matrix or callable
+    class Data : public SharedHandle::Object {
+    public:
+      const int n; ///< Number of sites
+      const IntSharedArray matrix; ///< Row-major matrix, empty for a callable
+      const std::function<int(int,int)> function; ///< Computed distance
+      Data(int n, const IntArgs& matrix);
+      Data(int n, std::function<int(int,int)> function);
+      virtual ~Data(void);
+    };
+  public:
+    /** \brief Copy and validate an \a n by \a n row-major distance matrix
+     *
+     * Throws Int::OutOfLimits for invalid sizes or distances,
+     * Int::ArgumentSizeMismatch for a wrong number of entries, and
+     * Int::IllegalOperation for asymmetry or a nonzero diagonal.
+     */
+    GECODE_INT_EXPORT IntDistance(int n, const IntArgs& matrix);
+    /** \brief Compute distances on demand for \a n sites
+     *
+     * The callable must return a stable, symmetric, nonnegative distance
+     * within Int::Limits, and zero for equal indices. It must own or share
+     * its captured data, be safe for concurrent calls, and not depend on a
+     * Space. Construction does not evaluate it or materialize a matrix.
+     * Results are checked for range and a zero diagonal when evaluated;
+     * symmetry is the caller's responsibility.
+     * Throws Int::OutOfLimits for an invalid site count and InvalidFunction
+     * for an empty callable.
+     */
+    GECODE_INT_EXPORT IntDistance(int n, std::function<int(int,int)> function);
+    /// Number of sites
+    int size(void) const;
+    /// Distance between valid indices \a a and \a b
+    int operator ()(int a, int b) const;
+  };
+
+  /// Organization of forward-bound minimum-distance propagation
+  enum class MinDistancePropKind {
+    MDP_DECOMPOSED,    ///< One propagator per selected-position pair
+    MDP_SINGLE         ///< One propagator with advisors and cached pair maxima
+  };
+  /// One propagator per selected-position pair
+  static constexpr MinDistancePropKind MDP_DECOMPOSED =
+    MinDistancePropKind::MDP_DECOMPOSED;
+  /// One propagator with advisors and cached pair maxima
+  static constexpr MinDistancePropKind MDP_SINGLE =
+    MinDistancePropKind::MDP_SINGLE;
+
+  /** \brief Post \f$z=\min_{i<j}d(x_i,x_j)\f$
+   *
+   * The default organization is MDP_SINGLE.
+   * Uses forward pruning from assigned endpoints and pairwise upper bounds
+   * on \a z. Both organizations implement the same filtering. MDP_DECOMPOSED
+   * retains separate actors and failure counts; MDP_SINGLE retains one
+   * actor, linear advisor state, and a quadratic array of pair witnesses.
+   * This is incomplete propagation, not full bounds or domain consistency.
+   *
+   * The forward-bound and conflict-matching algorithms follow
+   * M. Z. Lagerkvist, Propagation Algorithms for the Minimum-Distance
+   * Constraint over Selected Points, ModRef 2026.
+   *
+   * A separate greedy conflict-matching upper bound is enabled by default.
+   * IPL_BASIC disables it; IPL_ADVANCED and IPL_BASIC_ADVANCED enable it
+   * together with forward propagation. The matching certificate is weakly
+   * monotonic and may miss pruning. It uses integer thresholds and O(d.size())
+   * temporary storage, without constructing a graph or distance-level array.
+   *
+   * Domains in \a x are restricted to valid site indices; repeated sites
+   * and repeated variables are permitted. Post distinctness separately when
+   * needed. Throws Int::TooFewArguments if fewer than two positions are
+   * given, and Int::IllegalOperation for an unknown organization.
+   */
+  GECODE_INT_EXPORT void
+  minimum_distance(Home home, const IntVarArgs& x, IntVar z,
+                   const IntDistance& d, IntPropLevel ipl=IPL_DEF,
+                   MinDistancePropKind kind=MDP_SINGLE);
+  /** \brief Post the minimum-distance relation with pair requirements
+   *
+   * In addition, requires \f$d(x_i,x_j)\geq r_{ij}\f$. The \a r matrix is
+   * row-major, symmetric, nonnegative, zero on its diagonal, and has
+   * x.size() squared entries. Requirements are inclusive. Positions are
+   * labelled: ordering them is only a valid symmetry break if requirements
+   * are invariant under the corresponding permutations.
+   *
+   * Has the same propagation and argument requirements as the other
+   * overload. Throws Int::ArgumentSizeMismatch for a wrong matrix size,
+   * Int::OutOfLimits for invalid requirements, and Int::IllegalOperation
+   * for asymmetry or a nonzero diagonal.
+   */
+  GECODE_INT_EXPORT void
+  minimum_distance(Home home, const IntVarArgs& x, IntVar z,
+                   const IntDistance& d, const IntArgs& r,
+                   IntPropLevel ipl=IPL_DEF, MinDistancePropKind kind=MDP_SINGLE);
+  //@}
+
+}
+
+#include <gecode/int/min-distance.hpp>
+
 namespace Gecode {
 
   /**