added 2D dummy problem

mluq/src/problems/IStochasticProblem.cpp

@@ -21,5 +21,7 @@ CreateStochasticDummyProblem(const std::string &problemName, const Meshes &meshe
     return new CMatrixGeneratorProblem(meshes);
   if (problemName == "SparseGrid1DGeneratorProblem")
     return new SparseGrid1DGeneratorProblem(meshes);
+  if (problemName == "SparseGrid2DGeneratorProblem")
+    return new SparseGrid2DGeneratorProblem(meshes);
   Exit(problemName + " not found")
 }
\ No newline at end of file

mluq/src/problems/IStochasticProblem.hpp

@@ -206,6 +206,30 @@ public:
   }
 };
 
+class SparseGrid2DGeneratorProblem : public StochasticDummyProblem {
+  SparseGridGenerator generator;
+public:
+  explicit SparseGrid2DGeneratorProblem(const Meshes &meshes) :
+    StochasticDummyProblem(meshes),
+    generator(SparseGridGenerator(meshes, 2, 0, 6)) {}
+
+  void DrawSample(const SampleID &id) override {
+    generator.DrawSample(id);
+  }
+
+  double FunctionEvaluation() override {
+    RVector sample = this->generator.EvalSample();
+    double y1 = sample[0];
+    double y2 = sample[1];
+    return std::exp(-y1*y1) * std::cos(y2);
+  }
+
+  string Name() const override {
+    return "SparseGrid2DGeneratorProblem";
+  }
+};
+
+
 StochasticDummyProblem *
 CreateStochasticDummyProblem(const std::string &problemName, const Meshes &meshes);