DESCR("computation cost factors", "[%s]", comp_cost.to_string().c_str());
DESCR("communication cost factors", "[%s]", comm_cost.to_string().c_str());
DESCR("minimum duration between iterations", "%g", min_iter_duration);
DESCR("computation cost factors", "[%s]", comp_cost.to_string().c_str());
DESCR("communication cost factors", "[%s]", comm_cost.to_string().c_str());
DESCR("minimum duration between iterations", "%g", min_iter_duration);