Improve error messages for LinearProgramming

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/eval/Errors.java

@@ -183,6 +183,7 @@ public static void initGeneralMessages() {
       "listrp", "List or SparseArray or structured array expected at position `1` in `2`.", //
       "locked", "Symbol `1` is locked.", //
       "lowlen", "Required length `1` is smaller than maximum `2` of support of `3`.", //
+      "lpsnf", "No solution can be found that satisfies the constraints.", //
       "lslc", "Coefficient matrix and target vector or matrix do not have the same dimensions.", //
       "lstpat", "List or pattern matching a list expected at position `1` in `2`.", //
       "lvlist", "Local variable specification `1` is not a List.", //

symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/LinearProgramming.java

@@ -2,9 +2,8 @@
 
 import java.util.ArrayList;
 import java.util.Collection;
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.hipparchus.exception.MathIllegalArgumentException;
+import org.hipparchus.exception.MathIllegalStateException;
 import org.hipparchus.exception.MathRuntimeException;
 import org.hipparchus.optim.PointValuePair;
 import org.hipparchus.optim.linear.LinearConstraint;
@@ -15,6 +14,7 @@
 import org.hipparchus.optim.linear.Relationship;
 import org.hipparchus.optim.linear.SimplexSolver;
 import org.hipparchus.optim.nonlinear.scalar.GoalType;
+import org.matheclipse.core.basic.Config;
 import org.matheclipse.core.eval.Errors;
 import org.matheclipse.core.eval.EvalEngine;
 import org.matheclipse.core.eval.interfaces.AbstractFunctionEvaluator;
@@ -77,7 +77,6 @@
  * </pre>
  */
 public class LinearProgramming extends AbstractFunctionEvaluator {
-  private static final Logger LOGGER = LogManager.getLogger();
 
   public LinearProgramming() {
     super();
@@ -138,13 +137,15 @@ public IExpr numericEval(final IAST ast, EvalEngine engine) {
                 if (sn != null) {
                   constraints.add(new LinearConstraint(arg2D, Relationship.GEQ, sn.doubleValue()));
                 } else {
-                  LOGGER.log(engine.getLogLevel(), "Numeric vector or number expected!");
-                  return F.NIL;
+                  // `1`.
+                  return Errors.printMessage(ast.topHead(), "error",
+                      F.list(F.$str("Numeric vector or number expected.")), engine);
                 }
               }
             } else {
-              LOGGER.log(engine.getLogLevel(), "Numeric vector expected!");
-              return F.NIL;
+              // `1`.
+              return Errors.printMessage(ast.topHead(), "error",
+                  F.list(F.$str("Numeric vector expected.")), engine);
             }
           }
           SimplexSolver solver = new SimplexSolver();
@@ -156,11 +157,24 @@ public IExpr numericEval(final IAST ast, EvalEngine engine) {
         }
       }
     } catch (MathIllegalArgumentException miae) {
+      if (Config.DEBUG) {
+        miae.printStackTrace();
+      }
       // `1`.
-      return Errors.printMessage(ast.topHead(), "error", F.list(F.$str(miae.getMessage())),
-          engine);
+      return Errors.printMessage(ast.topHead(), "error", F.list(F.$str(miae.getMessage())), engine);
+    } catch (MathIllegalStateException mise) {
+      if (Config.DEBUG) {
+        mise.printStackTrace();
+      }
+      // No solution can be found that satisfies the constraints.
+      return Errors.printMessage(ast.topHead(), "lpsnf", F.CEmptyList, engine);
     } catch (MathRuntimeException mre) {
-      LOGGER.log(engine.getLogLevel(), ast.topHead(), mre);
+      if (Config.DEBUG) {
+        mre.printStackTrace();
+      }
+      // `1`.
+      return Errors.printMessage(ast.topHead(), "error", F.list(F.$str(mre.getMessage())), engine);
+
     }
     return F.NIL;
   }

symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/LinearOptimizationTest.java

@@ -32,4 +32,23 @@ public void testLinearProgramming() {
         "{0.6,0.0}");
   }
 
+  @Test
+  public void testLinearProgrammingNoFeasibleSolution() {
+    // message: LinearProgramming: No solution can be found that satisfies the constraints.
+    check("LinearProgramming({-2, -1,-2}, {{1, 2,0},{3,2,1},{0,1,0}}, {{5, -1},{4,-1},{3,1}})", //
+        "LinearProgramming({-2,-1,-2},{{1,2,0},{3,2,1},{0,1,0}},{{5,-1},{4,-1},{3,1}})");
+  }
+
+  @Test
+  public void testSystem803() {
+    // see
+    // http://google-opensource.blogspot.com/2009/06/introducing-apache-commons-math.html
+    check(
+        "LinearProgramming({-2, 1, -5}, {{1, 2, 0},{3, 2, 0},{0,1,0},{0,0,1}}, {{6,-1},{12,-1},{0,1},{1,0}})",
+        "{4.0,0.0,1.0}");
+    // message: LinearProgramming: inconsistent dimensions: 2 != 3.
+    check("LinearProgramming({-2, 1, -5}, {{1, 2},{3, 2},{0,1}},{{6,-1},{12,-1},{0,1}})", //
+        "LinearProgramming({-2,1,-5},{{1,2},{3,2},{0,1}},{{6,-1},{12,-1},{0,1}})");
+  }
+
 }

symja_android_library/matheclipse-core/src/test/java/org/matheclipse/core/system/MainTestCase.java

@@ -3717,19 +3717,6 @@ public void testSystem422() {
   // check("Plot(Sin(x),{x,0,10})", "");
   // };
 
-  @Test
-  public void testSystem803() {
-    // see
-    // http://google-opensource.blogspot.com/2009/06/introducing-apache-commons-math.html
-    check(
-        "LinearProgramming({-2, 1, -5}, {{1, 2, 0},{3, 2, 0},{0,1,0},{0,0,1}}, {{6,-1},{12,-1},{0,1},{1,0}})",
-        "{4.0,0.0,1.0}");
-    // creates unbounded error
-    // check("LinearProgramming({-2, 1, -5}, {{1, 2},{3, 2},{0,1}},
-    // {{6,-1},{12,-1},{0,1}})",
-    // "{4.0,0.0,1.0}");
-  }
-
   @Test
   public void testSystem804() {
     // check("Simplify(x*(x^2.00))", "x^3.0");