Fix error in affine view detection

chocoteam · Oct 12, 2023 · fd3f1e9 · fd3f1e9
1 parent 87cf1e5
commit fd3f1e9
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Showing 4 changed files with 31 additions and 37 deletions.
diff --git a/solver/src/main/java/org/chocosolver/solver/constraints/IIntConstraintFactory.java b/solver/src/main/java/org/chocosolver/solver/constraints/IIntConstraintFactory.java
@@ -2582,7 +2582,7 @@ default Constraint tree(IntVar[] succs, IntVar nbTrees, int offset) {
      * Get the list of values in the domains of vars
      *
      * @param vars an array of integer variables
-     * @return the list of values in the domains of vars
+     * @return the array of values in the domains of vars
      */
     default int[] getDomainUnion(IntVar... vars) {
         int m = vars[0].getLB(), M = vars[0].getUB(), j, k;
@@ -2640,7 +2640,8 @@ static Object[] variableUniqueness(Object[]... vars) {
         for (int i = 0; i < allvars.size(); i++) {
             for (int j = i + 1; j < allvars.size(); j++) {
                 if (allvars.get(i).equals(allvars.get(j))) {
-                    allvars.set(j, IntAffineView.make(allvars.get(i), 1, 0));
+                    // force the view to be created, no call to ref().intView() here !
+                    allvars.set(j, new IntAffineView<>(allvars.get(i), 1, 0));
                 }
             }
         }

diff --git a/solver/src/main/java/org/chocosolver/solver/variables/IViewFactory.java b/solver/src/main/java/org/chocosolver/solver/variables/IViewFactory.java
@@ -131,7 +131,18 @@ default IntVar intView(int a, IntVar var, int b) {
                     }
                 }
             }
-            return IntAffineView.make(var, a, b);
+            if (var instanceof IntAffineView) {
+                IntAffineView<?> view = (IntAffineView<?>) var;
+                int av = (view.p ? 1 : -1) * view.a * a;
+                int bv = view.a * b + view.b;
+                if (av == 1 && bv == 0) {
+                    return view.getVariable();
+                }else{
+                    return intView(av, view.getVariable(), bv);
+                }
+            } else {
+                return new IntAffineView<>(var, a, b);
+            }
         } else {
             int lb, ub;
             if (a > 0) {

diff --git a/solver/src/main/java/org/chocosolver/solver/variables/view/integer/IntAffineView.java b/solver/src/main/java/org/chocosolver/solver/variables/view/integer/IntAffineView.java
@@ -34,30 +34,21 @@
  */
 public final class IntAffineView<I extends IntVar> extends IntView<I> {
 
-    final boolean p; // positive
-    final int a;
-    final int b;
-
-
-    public static IntAffineView<IntVar> make(IntVar var, int a, int b) {
-        if (var instanceof IntAffineView) {
-            IntAffineView<?> view = (IntAffineView<?>) var;
-            return new IntAffineView<>(view.getVariable(), view.p & (a >= 0), view.a * Math.abs(a), view.a * b + view.b);
-        } else {
-            return new IntAffineView<>(var, a >= 0, Math.abs(a), b);
-        }
-    }
+    public final boolean p; // positive
+    public final int a;
+    public final int b;
 
     /**
-     * <i>y</i> is an affine view of <i>x</i>: <i>y = (-1)a*x + b</i>.
+     * <i>y</i> is an affine view of <i>x</i>: <i>y = a*x + b</i>.
      *
      * @param var a integer variable
+     * @param a   a coefficient
+     * @param b   a constant
      */
-    private IntAffineView(final I var, boolean p, int a, int b) {
-        super((p ? "" : "-") + a + ".(" + var.getName() + ") + " + b, var);
-        assert a > 0;
-        this.p = p;
-        this.a = a;
+    public IntAffineView(final I var, int a, int b) {
+        super(a + ".(" + var.getName() + ") + " + b, var);
+        this.p = a >= 0;
+        this.a = Math.abs(a);
         this.b = b;
     }
 

diff --git a/solver/src/test/java/org/chocosolver/solver/variables/view/integer/IntAffineViewTest.java b/solver/src/test/java/org/chocosolver/solver/variables/view/integer/IntAffineViewTest.java
@@ -65,7 +65,7 @@ public Object[][] configurations() {
     public void testNextValue(int a, int b, int... domain) {
         Model model = new Model();
         IntVar x = model.intVar("x", domain);
-        IntVar y = IntAffineView.make(x, a, b);
+        IntVar y = new IntAffineView<>(x, a, b);
 
         int[] values = Arrays.stream(domain).map(i -> (a * i) + b).sorted().toArray();
 
@@ -78,20 +78,11 @@ public void testNextValue(int a, int b, int... domain) {
         Assert.assertEquals(y.nextValue(values[2]), Integer.MAX_VALUE);
     }
 
-    @Test(groups = "1s")
-    public void testNextValue2() {
-        Model model = new Model();
-        IntVar x = model.intVar("x", 2, 9);
-        IntVar y = IntAffineView.make(x, 5, 7);
-
-
-    }
-
     @Test(groups = "1s", dataProvider = "configurations")
     public void testPreviousValue(int a, int b, int... domain) {
         Model model = new Model();
         IntVar x = model.intVar("x", domain);
-        IntVar y = IntAffineView.make(x, a, b);
+        IntVar y = new IntAffineView<>(x, a, b);
 
         int[] values = Arrays.stream(domain).map(i -> a * i + b).sorted().toArray();
 
@@ -108,7 +99,7 @@ public void testPreviousValue(int a, int b, int... domain) {
     public void testNextValueOut(int a, int b, int... domain) {
         Model model = new Model();
         IntVar x = model.intVar("x", domain);
-        IntVar y = IntAffineView.make(x, a, b);
+        IntVar y = new IntAffineView<>(x, a, b);
 
         int[] values = Arrays.stream(domain).map(i -> (a * i) + b).sorted().toArray();
         BitSet valuesOut = new BitSet();
@@ -129,7 +120,7 @@ public void testNextValueOut(int a, int b, int... domain) {
     public void testPreviousValueOut(int a, int b, int... domain) {
         Model model = new Model();
         IntVar x = model.intVar("x", domain);
-        IntVar y = IntAffineView.make(x, a, b);
+        IntVar y = new IntAffineView<>(x, a, b);
 
         int[] values = Arrays.stream(domain).map(i -> (a * i) + b).sorted().toArray();
         BitSet valuesOut = new BitSet();
@@ -151,7 +142,7 @@ public void testPreviousValueOut(int a, int b, int... domain) {
     public void testValueIterator(int a, int b, int... domain) {
         Model model = new Model();
         IntVar x = model.intVar("x", domain);
-        IntVar y = IntAffineView.make(x, a, b);
+        IntVar y = new IntAffineView<>(x, a, b);
 
         int[] values = Arrays.stream(domain).map(i -> a * i + b).sorted().toArray();
 
@@ -178,7 +169,7 @@ public void testValueIterator(int a, int b, int... domain) {
     public void testRangeIterator(int a, int b, int... domain) {
         Model model = new Model();
         IntVar x = model.intVar("x", domain);
-        IntVar y = IntAffineView.make(x, a, b);
+        IntVar y = new IntAffineView<>(x, a, b);
 
         int[] values = Arrays.stream(domain).map(i -> a * i + b).sorted().toArray();