Feature/proximal newton solver

Introduce a Riemannian Proximal-Newton Solver as an alternative for the Trust-Region Solver. Also add 3 cleanup commits.

dune/gfe/riemannianpnsolver.cc

@@ -216,10 +216,8 @@ void RiemannianProximalNewtonSolver<Basis,TargetSpace>::solve()
         CorrectionType corr(x_.size());
         corr = 0;
 
-        Dune::Timer gradientTimer;
-
         if (recomputeGradientHessian) {
-
+            Dune::Timer gradientTimer;
             assembler_->assembleGradientAndHessian(x_,
                                                    rhs,
                                                    *hessianMatrix_,
@@ -313,7 +311,7 @@ void RiemannianProximalNewtonSolver<Basis,TargetSpace>::solve()
             solved = false;
 
         if (instrumented_) {
-
+#if 0
             fprintf(fp, "Proximal newton step: %ld, regularization parameter: %g\n",
                     i, regularization);
 
@@ -376,8 +374,7 @@ void RiemannianProximalNewtonSolver<Basis,TargetSpace>::solve()
                 oldError = error;
 
             }
-
-
+#endif
         }
         double energy = 0;
         double modelDecrease = 0;
@@ -386,7 +383,7 @@ void RiemannianProximalNewtonSolver<Basis,TargetSpace>::solve()
             std::cout << i+1 << " proximal newton steps were taken, the maximum was reached." << std::endl << "Total solver time: " << totalSolverTime << " sec., total assembly time: " << totalAssemblyTime << " sec." << std::endl;
 
         if (solved) {
-            if (this->verbosity_ == NumProc::FULL)
+            if (this->verbosity_ == NumProc::FULL && rank==0)
                 std::cout << "Infinity norm of the correction: " << corrGlobalInfinityNorm << std::endl;
 
             if (corrGlobalInfinityNorm < this->tolerance_) {