def select_qadapter(self, pconfs):
        """
        Given a list of parallel configurations, pconfs, this method select an `optimal` configuration
        according to some criterion as well as the :class:`QueueAdapter` to use.

        Args:
            pconfs: :class:`ParalHints` object with the list of parallel configurations

        Returns:
            :class:`ParallelConf` object with the `optimal` configuration.
        """
        # Order the list of configurations according to policy.
        policy, max_ncpus = self.policy, self.max_cores
        pconfs = pconfs.get_ordered_with_policy(policy, max_ncpus)

        if policy.precedence == "qadapter":

            # Try to run on the qadapter with the highest priority.
            for qadpos, qad in enumerate(self.qads):
                possible_pconfs = [pc for pc in pconfs if qad.can_run_pconf(pc)]

                if qad.allocation == "nodes":
                #if qad.allocation in ["nodes", "force_nodes"]:
                    # Select the configuration divisible by nodes if possible.
                    for pconf in possible_pconfs:
                        if pconf.num_cores % qad.hw.cores_per_node == 0:
                            return self._use_qadpos_pconf(qadpos, pconf)

                # Here we select the first one.
                if possible_pconfs:
                    return self._use_qadpos_pconf(qadpos, possible_pconfs[0])

        elif policy.precedence == "autoparal_conf":
            # Try to run on the first pconf irrespectively of the priority of the qadapter.
            for pconf in pconfs:
                for qadpos, qad in enumerate(self.qads):

                    if qad.allocation == "nodes" and not pconf.num_cores % qad.hw.cores_per_node == 0:
                        continue # Ignore it. not very clean

                    if qad.can_run_pconf(pconf):
                        return self._use_qadpos_pconf(qadpos, pconf)

        else:
            raise ValueError("Wrong value of policy.precedence = %s" % policy.precedence)

        # No qadapter could be found
        raise RuntimeError("Cannot find qadapter for this run!")