Use truncate to apply ignore node for arbitrary types.

dune/solvers/iterationsteps/cgstep.cc

-// -*- tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// -*- tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 // vi: set et ts=8 sw=4 sts=4:
 
 #include <dune/solvers/common/canignore.hh>
+#include <dune/matrix-vector/genericvectortools.hh>
 
 template <class MatrixType, class VectorType, class Ignore>
 void CGStep<MatrixType, VectorType, Ignore>::check() const
@@ -14,9 +15,7 @@ void CGStep<MatrixType, VectorType, Ignore>::preprocess()
     // Compute the residual (r starts out as the rhs)
     this->mat_->mmv(*x_,r_);
     if (this->hasIgnore())
-        for (size_t i=0; i < r_.size(); ++i)
-            if (this->ignore()[i].any())
-                r_[i] = 0;
+      Dune::MatrixVector::Generic::truncate(r_, this->ignore());
 
     if (preconditioner_) {
         using CanIgnore_t = CanIgnore<Ignore>;
@@ -47,9 +46,7 @@ void CGStep<MatrixType, VectorType, Ignore>::iterate()
     r_.axpy(-alpha, q);                            // r_1     = r_0 - alpha_0 Ap_0
 
     if (this->hasIgnore())
-        for (size_t i=0; i < r_.size(); ++i)
-            if (this->ignore()[i].any())
-                r_[i] = 0;
+      Dune::MatrixVector::Generic::truncate(r_, this->ignore());
 
     if (preconditioner_)
         preconditioner_->apply(q, r_);