def mumps(self):
        """Call MUMPS, checking for errors in the return code.

        The desired job should have already been set using `ctx.set_job(...)`.
        As a convenience, you may wish to call `ctx.run(job=...)` which sets
        the job and calls MUMPS.
        """
        self._mumps_c(self.id)
        if self.id.infog[0] < 0:
            raise RuntimeError("MUMPS error: %d" % self.id.infog[0])