span class="n">itabref</span><span class="o">=</span><span class="n">irow</span><span class="p">(</span><span class="n">i1</span><span class="p">:</span><span class="n">i2</span><span class="p">),</span> <span class="n">rtab1</span><span class="o">=</span><span class="n">a_elt</span><span class="p">(</span><span class="n">i1</span><span class="p">:</span><span class="n">i2</span><span class="p">))</span>
      <span class="n">enddo</span>

      <span class="c">! assembly starting from the jcol, irow and a_