span 
class="cmti-12">Build the preconditioner for a given matrix. </span><span 
class="cmr-12">This is performed by the</span>
          <span 
class="cmr-12">routine </span><span class="obeylines-h"><span class="verb"><span 
class="cmtt-12">smoothers_build</span></span></span><span 
class="cmr-12">.</span></li></ol>
     <!--l. 48--><p class="noindent" ><span 
class="cmr-12">If the selected preconditioner is one-level, it is built in a single step, performed by</span>
     <span 
class="cmr-12">the routin