CPU Requirements Research Articles

Program F. MATINV for the solution of the sparse linear system [formula omitted] including normalisation

A program F. MATINV for the solution of the sparse linear system Ax = b has been designed by Zisserman and Caldwell. This paper describes an amendment to the program which incorporates an extra section in the Gaussian elimination subroutine MATINV. The aim is to make further savings on computer storage requirements by introducing the process of row normalisation. A comparison of CPU and storage requirements is included for a sparse band matrix with a range of dimensions.

A Decomposition Approach to the Economic Dispatch of Hydrothermal Systems

The objective of the predispatch of a hydroelectric system is to produce an hourly generation schedule that does not violate electrical constraints and meets weekly generation targets for each hydro plant. The predispatch can therefore be seen as a link between operation planing and the on-line generation scheduling. This paper presents a decomposition approach to the solution of the predispatch problem, which is modeled as a large-scale linear program and solved by Dantzig-Wolfe decomposition. The subproblems in this decomposition correspond to hourly optimal rescheduling problems and are solved by an efficient version of the Dual Simplex method. Core and CPU requirements are thus greatly reduced. A case study with the Brazilian Southeast netwrk is presented and discussed.

Fast computer calculation of ESR and nonlinear spin response spectra from the fast motion to the rigid lattice limits

Fast computer simulation of the electron spin resonance and adiabatic rapid passage spectra of spin labels characterized by rotational correlation times ranging from the fast motion to the rigid lattice limits is demonstrated. Calculations are based upon a modification of the stochastic Liouville equation for the density matrix which explicitly includes interaction of the spins with applied radiation and modulation fields. Several mathematical simplifications of previous calculations are demonstrated, permitting computation with core and CPU requirements compatible with small computers.

A model of memory contention in a paging machine

This paper is concerned with certain aspects of contention for main memory resources in a multiprogrammed computer system operating under demand paging. In the model presented, the number of page-frames of main memory allocated to a problem program varies in time. These changes in memory configuration are represented explicitly in the model, CPU requirements and page exception characteristics of program material being described statistically. Expressions for the distribution of the number of page-frames allocated to an executing program, the long run expected fraction of a program's execution time in a given number of page-frames, and the average execution interval of the multi-programmed load are obtained. It is pointed out heuristically and demonstrated numerically that an increase is obtainable in the average execution interval of the multiprogrammed load over that resulting from equal fixed partitioning of main memory.