Rectangular Full Packed Format for Cholesky's Algorithm: Factorization, Solution and Inversion

We describe a new data format for storing triangular, symmetric, and Hermitian matrices called RFPF (Rectangular Full Packed Format). The standard two dimensional arrays of Fortran and C (also known as full format) that are used to represent triangular and symmetric matrices waste nearly half of the storage space but provide high performance via the use of Level 3 BLAS. Standard packed format arrays fully utilize storage (array space) but provide low performance as there is no Level 3 packed BLAS. We combine the good features of packed and full storage using RFPF to obtain high performance via using Level 3 BLAS as RFPF is a standard full format representation. Also, RFPF requires exactly the same minimal storage as packed format. Each LAPACK full and/or packed triangular, symmetric, and Hermitian routine becomes a single new RFPF routine based on eight possible data layouts of RFPF. This new RFPF routine usually consists of two calls to the corresponding LAPACK full format routine and two calls to Level 3 BLAS routines. This means {\it no} new software is required. As examples, we present LAPACK routines for Cholesky factorization, Cholesky solution and Cholesky inverse computation in RFPF to illustrate this new work and to describe its performance on several commonly used computer platforms. Performance of LAPACK full routines using RFPF versus LAPACK full routines using standard format for both serial and SMP parallel processing is about the same while using half the storage. Performance gains are roughly one to a factor of 43 for serial and one to a factor of 97 for SMP parallel times faster using vendor LAPACK full routines with RFPF than with using vendor and/or reference packed routines

Ueber die Einwirkung des Broms auf Trimethylen unter verschiedenen Bedingungen

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Summary Hydrogeologic Assessment U.S. Department of Energy Pantex Plant, Carson County, Texas

In 1990, the Bureau of Economic Geology (BEG) and the Department of Geological Sciences (DOGS) at The University of Texas at Austin and the Water Resources Center (WRC) at Texas Tech University began a five-year program, funded by the Department of Energy (DOE) through the Governor's Office of the State of Texas, to characterize the geohydrology of Pantex Plant. The purpose of this work, which is summarized in this report, was to provide data and information that would assist in the remediation of contaminated sites at Pantex and support the State of Texas in its review of the Department of Energy's (DOE's) remediation program. The results of this investigation describe the physical setting and heterogeneities that control movement and distribution of contaminants and the processes that affect rates and fate of contaminants. The fate and distribution of contaminants, the selection and application of appropriate remediation approaches, the evaluation of the effectiveness of remediation technologies, and the proper monitoring of the affected environment all depend on knowledge of the controls and rates of active processes at Pantex Plant.Bureau of Economic Geolog

Electromagnetic Delineation of Saline Ground-Water Plumes in Alluvium and Bedrock Along the Canadian River Between Ute Reservoir and Rana Canyon, New Mexico

Lake Meredith, which supplies water for domestic use to all major Texas cities on the Southern High Plains, exceeds the Texas Water Commission's standards for chloride and sulfate content (300 mg/L) as well as the U.S. Environmental Protection Agency's standard for sodium (250 mg/L). Location of the sources of these solutes is a necessary first step in any remediation effort to reduce the salinity of river waters and ultimately the salinity of Lake Meredith. Initial examination of the conductivity and salinity of Canadian River waters, which supply Lake Meredith, was completed in May 1992. The results of these analyses indicated that saline ground-water discharge areas were concentrated in the river segment between the Ute Reservoir and Rana Canyon, New Mexico, and that ground-water conductivity surveys should be focused along this part of the river. This assessment of the distribution of saline ground-water plumes in alluvium and bedrock along the Canadian River between the Ute Reservoir and Rana Canyon, New Mexico, is an integrated geological and geophysical study that incorporates both the use of extensive ground conductivity measurements and joint measurements. These data are used to identify sites of potential ground-water discharge to the river and to suggest preferred ground-water flow paths.Bureau of Economic Geolog

Sensitive gravity-gradiometry with atom interferometry: progress towards an improved determination of the gravitational constant

We here present a high sensitivity gravity-gradiometer based on atom interferometry. In our apparatus, two clouds of laser-cooled rubidium atoms are launched in fountain configuration and interrogated by a Raman interferometry sequence to probe the gradient of gravity field. We recently implemented a high-flux atomic source and a newly designed Raman lasers system in the instrument set-up. We discuss the applications towards a precise determination of the Newtonian gravitational constant G. The long-term stability of the instrument and the signal-to-noise ratio demonstrated here open interesting perspectives for pushing the measurement precision below the 100 ppm level