Implements the achievedTol interface for the GmresPolySolMgr

A user request has been received for the Gmres polynomial preconditioned
solver to return the achieved tolerance from the outer iterative method.
This is best done through the achievedTol() method in the abstract solver
manager interface, that is utilized by most of the iterative methods.
This commit implements that function call and includes a test of that call
to ensure it works.

packages/belos/src/BelosGmresPolySolMgr.hpp

@@ -152,9 +152,9 @@ template<class ScalarType, class MV, class OP>
 class GmresPolySolMgr : public SolverManager<ScalarType,MV,OP> {
 private:
 
-  typedef MultiVecTraits<ScalarType,MV> MVT;
-  typedef Teuchos::ScalarTraits<ScalarType> STS;
   typedef typename Teuchos::ScalarTraits<ScalarType>::magnitudeType MagnitudeType;
+
+  typedef Teuchos::ScalarTraits<MagnitudeType> MTS;
   typedef Belos::GmresPolyOp<ScalarType,MV,OP> gmres_poly_t;
   typedef Belos::GmresPolyMv<ScalarType,MV>    gmres_poly_mv_t;
 
@@ -217,6 +217,26 @@ class GmresPolySolMgr : public SolverManager<ScalarType,MV,OP> {
    */
   Teuchos::RCP<const Teuchos::ParameterList> getCurrentParameters() const override { return params_; }
 
+  /*! \brief Tolerance achieved by the last \c solve() invocation.
+    
+     This is the maximum over all right-hand sides' achieved
+     convergence tolerances, and is set whether or not the solve
+     actually managed to achieve the desired convergence tolerance.
+    
+     \warning This solver manager may be use as either a polynomial
+       preconditioned iterative method or a polynomial preconditioner.
+       In the later case, where a static polynomial is being applied
+       through each call to solve(), there is not an outer solve that 
+       can provide the achieved tolerance.
+     \warning This result may not be meaningful if there was a loss
+       of accuracy during the outer solve.  You should first call \c
+       isLOADetected() to check for a loss of accuracy during the
+       last solve.
+  */
+    MagnitudeType achievedTol() const override {
+      return achievedTol_;
+    }
+
   /*! \brief Return the timers for this object.
    *
    * The timers are ordered as follows:
@@ -331,7 +351,7 @@ class GmresPolySolMgr : public SolverManager<ScalarType,MV,OP> {
 #endif
 
   // Current solver values.
-  MagnitudeType polyTol_;
+  MagnitudeType polyTol_, achievedTol_;
   int maxDegree_, numIters_;
   int verbosity_;
   bool hasOuterSolver_;
@@ -363,6 +383,7 @@ template<class ScalarType, class MV, class OP>
 GmresPolySolMgr<ScalarType,MV,OP>::GmresPolySolMgr () :
   outputStream_ (Teuchos::rcp(outputStream_default_,false)),
   polyTol_ (DefaultSolverParameters::polyTol),
+  achievedTol_(MTS::zero()),
   maxDegree_ (maxDegree_default_),
   numIters_ (0),
   verbosity_ (verbosity_default_),
@@ -689,6 +710,7 @@ ReturnType GmresPolySolMgr<ScalarType,MV,OP>::solve ()
     ret = solver->solve();
     numIters_ = solver->getNumIters();
     loaDetected_ = solver->isLOADetected();
+    achievedTol_ = solver->achievedTol();
 
   } // if (hasOuterSolver_ && maxDegree_)
   else if (hasOuterSolver_) {
@@ -704,12 +726,14 @@ ReturnType GmresPolySolMgr<ScalarType,MV,OP>::solve ()
     ret = solver->solve();
     numIters_ = solver->getNumIters();
     loaDetected_ = solver->isLOADetected();
+    achievedTol_ = solver->achievedTol();
 
   }
   else if (maxDegree_) {
 
     // Apply the polynomial to the current linear system
     poly_Op_->ApplyPoly( *problem_->getRHS(), *problem_->getLHS() );
+    achievedTol_ = MTS::one();
 
   }
 

packages/belos/test/BlockGmres/test_hybrid_gmres_complex_hb.cpp

@@ -249,8 +249,9 @@ int main(int argc, char *argv[]) {
     //
     Belos::ReturnType ret = solver->solve();
     //
-    // Compute actual residuals.
+    std::cout << "Belos::GmresPolySolMgr returned achievedTol: " << solver->achievedTol() << std::endl << std::endl;
     //
+    // Compute actual residuals.
     RCP<MyMultiVec<ST> > temp = rcp( new MyMultiVec<ST>(dim,numrhs) );
     OPT::Apply( *A, *soln, *temp );
     MVT::MvAddMv( one, *rhs, -one, *temp, *temp );