Number crunching

Number Crunching. We poke into a general discussion and hear "I gather data over periods of time. Later, I do my analysis, not with one sample, but with a dozen or a hundred samples. Then I put it all together. What you might think of in your interpretation may not be the interpretation you want to rest on a year from now. When you go back and put it all together, you may want to go back to the raw data. ... 

But this year, an arm of Britain s government health care system, relying on some economists number-crunching, issued a preliminary ruling calling on doctors to stop prescribing the drugs. 

Now for the number crunching. Disregarding uncertainties for a moment, we know that F = 2.00300 = 8.00 The uncertainty is obtained from the equation above ... 

The use of computers in science is widespread. Without powerful number-crunching facilities at his disposal, the modern scientist would be greatly handicapped, unable to perform the thousands or millions of calculations required to analyze his data or explore the implications of his favorite theory. He (or his assistant) thus requires at least some familiarity with computers, the programming of computers, and the methods which might be used by computers to solve his problems. An entire branch of mathematics, numerical analysis, exists to analyze the behavior of numerical algorithms. 

The initial idea for this book was put forward by Professor Dusan Hadzi, one of the earliest promoters of the use of computers in the field of chemistry. Initially the book was intended to cover all aspects of the use of computers in chemistry with the emphasis on number-crunching and information systems. However, with the rapid... 

The book is aimed at those who have to use statistics, but have no ambition to become statisticians per se. It avoids getting bogged down in calculation methods and focuses instead on crucial issues that surround data generation and analysis (sample size estimation, interpretation of statistical results, the hazards of multiple testing, potential abuses, etc.). In this day of statistical packages, it is the latter that cause the real problems, not the number-crunching. 

The work which my associates and I have done in the use ot text as data by chemists and for chemists draws on two sources. The first ot these is computer text processing. It is even more clear today than it was 13 years ago when this work was started that computers may not only be used for number crunching but for a number ot other jobs in which letters and words as well as numbers can be used. Tasks such as extracting, sorting, reformatting, associating, and counting can be done not only with numeric information, but also with alphanumeric information. Whereas such operations may have been useful but esoteric 13 years ago, the tremendous use ot word... 

We have described some of the software that already exists and which already is applicable to investigations of protein structure. But if these calculations can already be accomplished, why do we need supercomputers In some cases, such as molecular dynamics, the question is one of brute number-crunching power — a faster computer will permit simulations of the motions of larger molecules over longer time intervals. But in other cases the question is not one of feasibility vs. infeasibility of the calculation, but in the speed with which the calculation can be completed relative to the time scale of interactive computing. Supercomputers may, in some cases, be able to convert certain tasks that must currently be run in batch mode to tasks that can be run interactively. This opens new doors. 

The approaches are divided into those which do not take frequency into account (except for relaxation phenomena) and therefore are "static" theories and those which take frequency into account, generally by a scattering approach. The latter, "dynamic" theories, when reduced to the low frequency or quasi-static limit, usually compare favorably with the static theories. Some approaches take multiple scattering into account and cannot be solved in closed form. These require elaborate computer number crunching techniques (5). 

The emergence of molecular modeling and computational into a discipline has been closely associated with advances in computer hardware, computer graphics, and software. The availability of more sophisticated number-crunching power has allowed scientists to calculate the properties oflarger and larger molecules. With the advent of supercomputers, dynamics calculations on biomolecules surrounded by an environment of water are becoming common. 

The math coprocessor is used to improve the processor s number-crunching speed. It does not, however, increase the speed of simple additions and subtractions. What it does is increase the speed of calculations that involve floating decimal point operations (such as calculations for algebra and statistics). Since the introduction of the 486, the math coprocessor has been built into the processor. CPU... 

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