hing (a.k.a. heavy connectivity matching) <br>
      <span style="font-style: italic;">ipm</span> - inner product
matching (a.k.a. heavy connectivity matching) <br>
      <span style="font-style: italic;">c-ipm</span> -&nbsp; column
ipm;&nbsp; faster method based on ipm within processor columns <br>
      <span style="font-style: italic;">a-ipm </span>- alternate
between fast method (l-ipm ) and ipm <br>
      <span style="font-style: italic;">l-ipm </span>-&nbsp; local ipm
on each processor. Fastest option