message: Fix custom_matrix example to use stopping criterion which are now required.
diff: @@ -307,7 +307,8 @@ int main(int argc, char *argv[])
  }
  // Get number of discretization points
  - const int discretization_points = argc >= 2 ? std::atoi(argv[1]) : 100;
  + const unsigned int discretization_points =
  + argc >= 2 ? std::atoi(argv[1]) : 100u;
  const auto executor_string = argc >= 3 ? argv[2] : "reference";
  // Figure out where to run the code
  @@ -338,8 +339,16 @@ int main(int argc, char *argv[])
  // Generate solver and solve the system
  cg::Factory::create()
  + .with_criterion(
  + gko::stop::Combined::Factory::create()
  + .with_criteria(
  + gko::stop::Iteration::Factory::create()
  .with_max_iters(discretization_points)
  - .with_rel_residual_goal(1e-6)
  + .on_executor(exec),
  + gko::stop::ResidualNormReduction<>::Factory::create()
  + .with_reduction_factor(1e-6)
  + .on_executor(exec))
  + .on_executor(exec))
  // something fails here:
  // .with_preconditioner(bj::create(exec, 32))
  .on_executor(exec)
  