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ADF95 is a tool to automatically calculate numerical first derivatives for any mathematical expression as a function of user defined independent variables. Accuracy of derivatives is achieved within machine precision. ADF95 may be applied…

Mathematical Software · Computer Science 2007-05-23 Christian W. Straka

Here, we report orbital-free density-functional theory (OF DFT) molecular dynamics simulations of the displacement cascade in aluminum. The electronic effect is our main concern. The displacement threshold energies are calculated using OF…

Materials Science · Physics 2017-09-26 Ruizhi Qiu

We show that Automatic Differentiation (AD) operators can be provided in a dynamic language without sacrificing numeric performance. To achieve this, general forward and reverse AD functions are added to a simple high-level dynamic…

Programming Languages · Computer Science 2016-11-11 Jeffrey Mark Siskind , Barak A. Pearlmutter

We present the first calculations of the inelastic part of the dynamical structure factor (DSF) for warm dense matter (WDM) using Time-Dependent Orbital-Free Density Functional Theory (TD-OF-DFT) and Mixed-Stochastic-Deterministic (mixed)…

Plasma Physics · Physics 2024-11-05 Alexander J. White

A key ingredient to achieving intelligent behavior is physical understanding that equips robots with the ability to reason about the effects of their actions in a dynamic environment. Several methods have been proposed to learn dynamics…

Robotics · Computer Science 2020-01-24 David Millard , Eric Heiden , Shubham Agrawal , Gaurav S. Sukhatme

We investigate the automatic differentiation of hybrid models, viz. models that may contain delays, logical tests and discontinuities or loops. We consider differentiation with respect to parameters, initial conditions or the time. We…

Systems and Control · Computer Science 2017-06-13 John Masse , Clara Masse , François Ollivier

The successes of deep learning, variational inference, and many other fields have been aided by specialized implementations of reverse-mode automatic differentiation (AD) to compute gradients of mega-dimensional objectives. The AD…

Machine Learning · Computer Science 2021-03-16 Deniz Oktay , Nick McGreivy , Joshua Aduol , Alex Beatson , Ryan P. Adams

An important field in robotics is the optimization of controllers. Currently, robots are often treated as a black box in this optimization process, which is the reason why derivative-free optimization methods such as evolutionary algorithms…

Neural and Evolutionary Computing · Computer Science 2018-11-27 Jonas Degrave , Michiel Hermans , Joni Dambre , Francis wyffels

We prove that functions over the reals computable in polynomial time can be characterised using discrete ordinary differential equations (ODE), also known as finite differences. We also provide a characterisation of functions computable in…

Computational Complexity · Computer Science 2024-02-15 Manon Blanc , Olivier Bournez

Since the advent of mesh-free methods as a tool for the numerical analysis of systems of Partial Differential Equations (PDEs), many variants of differential operator approximation have been proposed. In this work, we propose a local…

Numerical Analysis · Mathematics 2022-03-07 Mitja Jančič , Gregor Kosec

The formation of the large-scale structure, the evolution and distribution of galaxies, quasars, and dark matter on cosmological scales, requires numerical simulations. Differentiable simulations provide gradients of the cosmological…

Instrumentation and Methods for Astrophysics · Physics 2022-11-21 Yin Li , Libin Lu , Chirag Modi , Drew Jamieson , Yucheng Zhang , Yu Feng , Wenda Zhou , Ngai Pok Kwan , François Lanusse , Leslie Greengard

The real-time electronic dynamics on material surfaces is critically important to a variety of applications. However, their simulations have remained challenging for conventional methods such as the time-dependent density-functional theory…

Chemical Physics · Physics 2015-06-16 Rulin Wang , Dong Hou , Xiao Zheng

Machine learning (ML) of kinetic energy functionals (KEF) for orbital-free density functional theory (OF-DFT) holds the promise of addressing an important bottleneck in large-scale ab initio materials modeling where sufficiently accurate…

Materials Science · Physics 2025-04-10 Sergei Manzhos , Johann Luder , Pavlo Golub , Manabu Ihara

In the present work, we investigate the computational efficiency afforded by higher-order finite-element discretization of the saddle-point formulation of orbital-free density functional theory. We first investigate the robustness of viable…

Computational Physics · Physics 2015-05-30 Phani Motamarri , Mrinal Iyer , Jaroslaw Knap , Vikram Gavini

We validate the application of our recent orbital-free density functional theory (DFT) approach, [Phys. Rev. Lett. 113, 155006 (2014)], for the calculation of ionic and electronic transport properties of dense plasmas. To this end, we…

Plasma Physics · Physics 2015-12-16 Travis Sjostrom , Jérôme Daligault

Algorithms that use derivatives of governing equations have accelerated rigid robot simulations and improved their accuracy, enabling the modeling of complex, real-world capabilities. However, extending these methods to soft and hybrid…

Robotics · Computer Science 2024-11-08 Anup Teejo Mathew , Frederic Boyer , Vincent Lebastard , Federico Renda

In the context of Gaussian process regression with functional inputs, it is common to treat the input as a vector. The parameter space becomes prohibitively complex as the number of functional points increases, effectively becoming a…

Methodology · Statistics 2022-09-02 Luis Damiano , Margaret Johnson , Joaquim Teixeira , Max D. Morris , Jarad Niemi

Automatic differentiation is everywhere, but there exists only minimal documentation of how it works in complex arithmetic beyond stating "derivatives in $\mathbb{C}^d$" $\cong$ "derivatives in $\mathbb{R}^{2d}$" and, at best, shallow…

Mathematical Software · Computer Science 2024-12-11 Nicholas Krämer

We present an efficient method for propagating the time-dependent Kohn-Sham equations in free space, based on the recently introduced Fourier contour deformation (FCD) approach. For potentials which are constant outside a bounded domain,…

Chemical Physics · Physics 2023-07-10 Jason Kaye , Alex Barnett , Leslie Greengard , Umberto De Giovannini , Angel Rubio

The need to efficiently calculate first- and higher-order derivatives of increasingly complex models expressed in Python has stressed or exceeded the capabilities of available tools. In this work, we explore techniques from the field of…

Machine Learning · Computer Science 2018-09-27 Bart van Merriënboer , Dan Moldovan , Alexander B Wiltschko