Matrix Manipulator

In computation involving matrices it is frequently necessary to interchange or rearrange rows or columns of a matrix. If the work is being done longhand or with a desk calculator, it is desirable to be able to perform the rearrangement without having to erase or rewrite numbers. In mathematics, matrix addition or subtraction, multiplication or the matrix product or any other arithmetic operation is a binary operation that produces a matrix from two matrices. The matrix manipulator was devised for the use in the Bureau’s statistical Engineering Laboratory for calculation with incidence matrices, i.e., matrices whose element are all 0’s or 1’s. So, through this project we will show how the matrix manipulation is taking place using MIPS programming language. MIPS is a reduced instruction set computer set architecture developed by MIPS Technologies. The early MIPS architecture was 32-bit with 64-bit versions added later. Also, the project is compiled to show Matrix addition of two different matrices, subtraction of two different matrices, multiplication, transpose, determinant, scaling of matrix.

ENIAC and Its Contemporaries Meet the “Stored Program Concept”

Having explored ENIAC’s actual use and the programs it ran the authors shift to a more abstract analytical level. Previous discussion of the invention of the modern computer has focused on the “stored program concept” as the crucial innovation setting modern computers apart from their more limited predecessors. The authors explore the origins of this phrase and its changing meaning over time. They look in detail at a 1944 document produced by J. Presper Eckert and sometimes claimed as a first statement of this concept, showing that it actually describes an electronic desk calculator. The authors summarize ENIAC’s capabilities after conversion and to compare these on both practical and theoretical levels with the 1945 EDVAC design and with several other early computers. This supports a balanced appraisal of the senses in which the converted ENIAC did and did not constitute an initial implementation of the key ideas from the 1945 design. The chapter argues for an appraisal of early computers better grounded in the historical realities of documented use, and against a widespread fixation on the notion of “universality” based on a school of theoretical computer science that gained prominence years later.

Vessel-length distribution in stems of some American woody plants

Vessel-length distributions in some trees, shrubs, and a vine have been calculated from measurements of particle penetration and of air-volume flow through the xylem. In shrubs and diffuse-porous species, longest vessels were about 1 m long, but most of them were much shorter, the largest percentage in the 0–10 cm length class. In the two ring-porous species investigated (Quercus rubra and Fraxinus americana), the longest vessels often were as long as the tree's stem, but most of them were much shorter. In the grapevine (Vitis labrusca) which has large-diameter vessels (ca. 300 μm) a small percentage of the vessels was 8 m, but most of them were less than 5 m long. In a given species, lengths of the longest vessel were quite variable, but the distribution of the short lengths was more constant. In general, vessel lengths are correlated with vessel diameters: wide vessels are longer. Even in diffuse-porous species, the slightly narrower latewood vessels are somewhat shorter than the wider early wood vessels. The method is a simplified version of that described by Skene and Balodis, but using a programmable desk calculator. It works best with diffuse-porous species in which vessels are randomly distributed in the stem, and less well in species with wide vessels, because as vessels reach the length of the stem itself, they cannot be randomly distributed.

Force Field Calculation with a Top Desk Calculator

A modified “Consistent Force Field ” method is described in which the energy minimization is carried out according to the Murtagh-Sargent method rather than the Newton-Raphson method and the number of non-bonded interactions is reduced to interactions between atoms separated by three bonds at the most. The smaller number of interaction terms allowed the programming of the method for a desk top calculator (HP-9810). Calculations are reported for a number of aliphatic molecules