Rice University, HiPerSoft, MS-41, 6100 S. Main, Houston, Texas 77005, USA. druths@rice.edu|Rice University, HiPerSoft, MS-41, 6100 S. Main, Houston, Texas 77005, USA. druths@rice.edu|Rice University, HiPerSoft, MS-41, 6100 S. Main, Houston, Texas 77005, USA. druths@rice.edu