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The C standard library or libc is the standard library for the C programming language, as specified in the ISO C standard. Starting from the original ANSI C standard, it was developed at the same time as the C library POSIX specification, which is a superset of it. Since ANSI C was adopted by the International Organization for Standardization, the C standard library is also called the ISO C library. The C standard library provides macros, type definitions and functions for tasks such as string handling, mathematical computations, input/output processing, memory management, and several other operating system services. Application programming interface (API) Header files The application programming interface (API) of the C standard library is declared in a number of s. Each header file contains one or more function declarations, data type definitions, and macros. After a long period of stability, three new header files (iso646.h, wchar.h, and wctype.h) were a

i-PI 2.0: A universal force engine for advanced molecular simulations

Sébastien Pierre Bienvenue, Michele Ceriotti, Bingqing Cheng, Alice Cuzzocrea, Benjamin Aaron Helfrecht, Przemyslaw Juda, Venkat Kapil, Robert Horst Meissner, Riccardo Petraglia, Mariana Rossi Carvalho, Gareth Aneurin Tribello, David Mark Wilkins

Progress in the atomic-scale modeling of matter over the past decade has been tremendous. This progress has been brought about by improvements in methods for evaluating interatomic forces that work by either solving the electronic structure problem explicitly, or by computing accurate approximations of the solution and by the development of techniques that use the Born-Oppenheimer (BO) forces to move the atoms on the BO potential energy surface. As a consequence of these developments it is now possible to identify stable or metastable states, to sample configurations consistent with the appropriate thermodynamic ensemble, and to estimate the kinetics of reactions and phase transitions. All too often, however, progress is slowed down by the bottleneck associated with implementing new optimization algorithms and/or sampling techniques into the many existing electronic-structure and empirical-potential codes. To address this problem, we are thus releasing a new version of the i-PI software. This piece of software is an easily extensible framework for implementing advanced atomistic simulation techniques using interatomic potentials and forces calculated by an external driver code. While the original version of the code (Ceriotti et al., 2014) was developed with a focus on path integral molecular dynamics techniques, this second release of i-PI not only includes several new advanced path integral methods, but also offers other classes of algorithms. In other words, i-PI is moving towards becoming a universal force engine that is both modular and tightly coupled to the driver codes that evaluate the potential energy surface and its derivatives. Program summary Program Title: i-PI Program Files doi: http://dx.doLorg/10.17632/x792grbm9g.1 Licensing provisions: GPLv3, MIT Programming language: Python External routines/libraries: NumPy Nature of problem: Lowering the implementation barrier to bring state-of-the-art sampling and atomistic modeling techniques to ab initio and empirical potentials programs. Solution method: Advanced sampling methods, including path-integral molecular dynamics techniques, are implemented in a Python interface. Any electronic structure code can be patched to receive the atomic coordinates from the Python interface, and to return the forces and energy that are used to integrate the equations of motion, optimize atomic geometries, etc. Restrictions: This code does not compute interatomic potentials, although the distribution includes sample driver codes that can be used to test different techniques using a few simple model force fields. (C) 2018 Elsevier B.V. All rights reserved.

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Isogeometric Analysis for the Elastic Wave Equation

Christoph Jäggli

In everyday life of an engineer, CAD (Computer Aided Design) and FE (Finite Element) programs play an important role. The two different structures, CAD and FE programs, use different mathematical functions. In CAD programs, so called NURBS find their applications while the standard functions used in FE programs are Lagrange polynomials. This differences in the structure of the two programs result in a significant effort of translation. The concept of Isogeometric Analysis tries to extend the FE method by using NURBS as basis for the analysis. In this report we give first an introduction to NURBS. We will see that, compared to a standard FE analysis, we have a richer repertory for refining a given NURBS basis. Then we will use NURBS as basis for analysis to solve numerically two problems of linear elasticity; an equilibrium problem and a simulation of an earthquake.

2013

RRB-Trees: Efficient Immutable Vectors

Tiark Rompf

Immutable vectors are a convenient data structure for functional programming and part of the standard library of modern languages like Clojure and Scala. The common implementation is based on wide trees with a fixed number of children per node, which allows fast indexed lookup and update operations. In this paper we extend the vector data type with a new underlying data structure, Relaxed Radix Balanced Trees (RRB-Trees), and show how this structure allows immutable vector concatenation, insert-at and splits in O(log N) time while maintaining the index, update and iteration speeds of the original vector data structure.

2011

i-PI 2.0: A universal force engine for advanced molecular simulations

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