A Comparison of Several Methods for Inverting Large Symmetric Positive Definite Matrices (open access)

A Comparison of Several Methods for Inverting Large Symmetric Positive Definite Matrices

ABS>The Gauss-Jordan, Choleski, congruent transformation, and rank annihilation methods for inverting large symmetric positive definite matrices were compared. An attempt was made to consider the effects of both condition and order of the matrix to be inverted on the closeness of the computed inverse to the exact inverse. Each method was programmed in FORTRAN using only single precision arithmetic. Then the error indicators were computed using double precision arithmetic so that the latter calculation was not a limiting factor. It was found that any one of the methods is satisfactory for a well-conditioned least squares matrix of order 10-30. However, when the matrix becomes ill- conditioned then the Gauss-Jordan method appears to be clearly superior (at least for the matrices studied). Algorithms and FORTRAN subroutines for each method are presented. (auth)
Date: May 13, 1963
Creator: Lietzke, M. H.; Stoughton, R. W. & Lietzke, M. P.
Object Type: Report
System: The UNT Digital Library
Development of Pulsed Neutron Application to Power Reactor Start-Up Procedures. Fourth Quarterly Progress Report, January 1-March 31, 1963 (open access)

Development of Pulsed Neutron Application to Power Reactor Start-Up Procedures. Fourth Quarterly Progress Report, January 1-March 31, 1963

Activities in a program to develop techniques in the use of pulsed neutron sources to measure shutdown parameters related to large thermal power reactors are reported. The experimental work centers around aspects of detecting neutrons in the presence of 10/sup 7/ r/hr gamma fields. Boric acid experiments and Humboldt Bay experiments are reported.
Date: May 13, 1963
Creator: Garelis, Edward & Meyer, Paul
Object Type: Report
System: The UNT Digital Library
Irradiation Processing Department Monthly Report: April 1963 (open access)

Irradiation Processing Department Monthly Report: April 1963

This document details activities of the Irradiation Processing Department during the month of August, 1958. A general summary is included at the start of the report, after which the report is divided into the following sections: Research and Engineering Operations; Production and Reactor Operations; Facilities Engineering Operation; Employee Relations Operation; and Financial Operation.
Date: May 13, 1963
Creator: Hanford Atomic Products Operation. Irradiation Processing Department.
Object Type: Report
System: The UNT Digital Library
Texas Attorney General Opinion: C-77 (open access)

Texas Attorney General Opinion: C-77

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Waggoner Carr, regarding a legal question submitted for clarification: Highways over which the authority of the Commissioners Court extends under the terms of Article 827a, Sec. 2, V.P.C.
Date: May 13, 1963
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History