Computing and Applied Mathematics Laboratory, National Institute of Standards and Technology, Gaithersburg, MD;IBM TJ Watson Research Center, H0-D06, 30 Saw Mill River Road, Hawthorne, NY and Computing and Applied Mathematics Laboratory, National Institute of Standards and Technology, Gaithersburg, MD;Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD;Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD