Don't represent (var|const) >= abs(...) as SOCP #192

ampl · Oct 7, 2024 · ec0e049 · ec0e049
1 parent 00478d9
commit ec0e049
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Showing 4 changed files with 35 additions and 5 deletions.
diff --git a/include/mp/flat/constr_2_expr.h b/include/mp/flat/constr_2_expr.h
@@ -698,6 +698,7 @@ class Constraints2Expr {
       ck.ConvertConstraint(ie.GetIndex());
       return true;
     }
+    return false;
   }
 
 

diff --git a/include/mp/flat/redef/conic/cones.h b/include/mp/flat/redef/conic/cones.h
@@ -386,8 +386,9 @@ class Convert1QC : public MCKeeper<MCType> {
         if (auto lhs_args = CheckSqrtXnXmNonneg(lint.var(iX)))
           return ContinueRotatedSOC(lint, iX, iY,
                                     lhs_args, rhs_args);
-        return ContinueStdSOC(lint.coef(iX), lint.var(iX),
-                              lint.coef(iY), rhs_args);
+        if (!rhs_args.is_from_abs_)          // not x >= abs(...)
+          return ContinueStdSOC(lint.coef(iX), lint.var(iX),
+                                lint.coef(iY), rhs_args);
       }
     } else if (1 == lint.size() &&           // const>=y.
                0.0 >= rhs*sens &&            // either ... <= rhs
@@ -396,9 +397,10 @@ class Convert1QC : public MCKeeper<MCType> {
       // it's -k*sqrt(...) <= rhs(>0), k>0,
       // which is always true TODO
       if (auto rhs_args = CheckNorm2(lint.var(0))) {
-        return ContinueStdSOC(std::fabs(rhs),
-                              int( MC().MakeFixedVar( 1.0 ) ),
-                              lint.coef(0), rhs_args);
+        if (!rhs_args.is_from_abs_)          // not const >= abs(...)
+          return ContinueStdSOC(std::fabs(rhs),
+                                int( MC().MakeFixedVar( 1.0 ) ),
+                                lint.coef(0), rhs_args);
       }
     }
     return false;
@@ -407,6 +409,7 @@ class Convert1QC : public MCKeeper<MCType> {
   /// Typedef for subexpression checkup result,
   /// whether it represents some part of an SOCP cone.
   struct ConeArgs {
+    bool is_from_abs_ {};            // No StdCone then
     std::vector<double> coefs_;
     std::vector<int> vars_;
     double const_term = 0.0;
@@ -488,6 +491,7 @@ class Convert1QC : public MCKeeper<MCType> {
     result.coefs_ = { 1.0 };
     result.vars_ = { arg_abs };
     result.res_vars_to_delete_ = { res_var };
+    result.is_from_abs_ = true;
     return result;
   }
 

diff --git a/test/end2end/cases/categorized/fast/conic/modellist.json b/test/end2end/cases/categorized/fast/conic/modellist.json
@@ -91,6 +91,14 @@
       "solve_result_num": 0
     }
   },
+  {
+    "name" : "socp_13_abs_stdcone",
+    "tags" : ["socp"],
+    "objective" : -40,
+    "values": {
+      "solve_result_num": 0
+    }
+  },
   {
     "name" : "expcones_01__plain",
     "objective" : 0.7821882953,

diff --git a/test/end2end/cases/categorized/fast/conic/socp_13_abs_stdcone.mod b/test/end2end/cases/categorized/fast/conic/socp_13_abs_stdcone.mod
@@ -0,0 +1,17 @@
+####################################
+# Test that we don't convert abs(x) <= 5 into a cone
+# TODO Also perform the actual test, now it's just for solving
+####################################
+
+var b1 binary;
+var b2 binary;
+var x >=-19 <=32;
+var y >= -12 <= 5;
+
+minimize Obj: b1 - b2 - x + 3*y;
+
+var charge_diff = abs(x-y);
+
+s.t. Con: b1 && b2 ==> x<=y;
+
+s.t. Cone: charge_diff <= if b1>=1 then 5 else 15;