50,618 research outputs found
NLINLS: a Differential Evolution based nonlinear least squares Fortran 77 program
This paper provides the list of Fortran 77 codes of nonlinear least squares using Differential Evolution as the minimizer algorithm. It has been tested on a number of difficult nonlinear least squares problems (taken from NIST, USA including CPC-X Software challenge problems). Help on how to use the program also is provided.Nonlinear least squares; Differential Evolution; Fortran 77
One Christian\u27s Perspective on Creation and Evolution
As a graduate student I took a course on FORTRAN, a widely used computer programming language. The author, with an obvious sense for the humorous, began his text with this epigram: “On no! Just what the world needs, another book on FORTRAN.” I begin my essay with a similar bemused foreboding, posing the question: “Do we really need yet one more essay on the evolution/creation controversy?” Who knows? But I do think that my own students and perhaps others will benefit from a discussion focused directly on the most difficult Biblical issues and that comes from a person within the evangelical community. The essay is organized as follows:
A. Personal StatementB. Resistance to Evolution C. Understanding the BibleD. Hard Questions about Genesis E. The Science of Origins F. Evolution as God’s Mechanism of Creatio
From Tensor Equations to Numerical Code -- Computer Algebra Tools for Numerical Relativity
In this paper we present our recent work in developing a computer-algebra
tool for systems of partial differential equations (PDEs), termed "Kranc". Our
work is motivated by the problem of finding solutions of the Einstein equations
through numerical simulations. Kranc consists of Mathematica based
computer-algebra packages, that facilitate the task of dealing with symbolic
tensorial calculations and realize the conversion of systems of partial
differential evolution equations into parallelized C or Fortran code.Comment: LaTeX llncs style, 9 pages, 1 figure, to appaer in the proceedings of
"SYNASC 2004 - 6th International Symposium on Symbolic and Numeric Algorithms
for Scientific Computing", Timisoara, Romania, September 26-30 200
APFEL: A PDF Evolution Library with QED corrections
Quantum electrodynamics and electroweak corrections are important ingredients
for many theoretical predictions at the LHC. This paper documents APFEL, a new
PDF evolution package that allows for the first time to perform DGLAP evolution
up to NNLO in QCD and to LO in QED, in the variable-flavor-number scheme and
with either pole or MSbar heavy quark masses. APFEL consistently accounts for
the QED corrections to the evolution of quark and gluon PDFs and for the
contribution from the photon PDF in the proton. The coupled QCD+QED equations
are solved in x-space by means of higher order interpolation, followed by
Runge-Kutta solution of the resulting discretized evolution equations. APFEL is
based on an innovative and flexible methodology for the sequential solution of
the QCD and QED evolution equations and their combination. In addition to PDF
evolution, APFEL provides a module that computes Deep-Inelastic Scattering
structure functions in the FONLL general-mass variable-flavor-number scheme up
to O(). All the functionalities of APFEL can be accessed via a
Graphical User Interface, supplemented with a variety of plotting tools for
PDFs, parton luminosities and structure functions. Written in Fortran 77, APFEL
can also be used via the C/C++ and Python interfaces, and is publicly available
from the HepForge repository.Comment: 34 pages, 5 figures. Final version, to be published in CPC. Several
corrections and improvements. Program available from
http://apfel.hepforge.org
Kranc: a Mathematica application to generate numerical codes for tensorial evolution equations
We present a suite of Mathematica-based computer-algebra packages, termed
"Kranc", which comprise a toolbox to convert (tensorial) systems of partial
differential evolution equations to parallelized C or Fortran code. Kranc can
be used as a "rapid prototyping" system for physicists or mathematicians
handling very complicated systems of partial differential equations, but
through integration into the Cactus computational toolkit we can also produce
efficient parallelized production codes. Our work is motivated by the field of
numerical relativity, where Kranc is used as a research tool by the authors. In
this paper we describe the design and implementation of both the Mathematica
packages and the resulting code, we discuss some example applications, and
provide results on the performance of an example numerical code for the
Einstein equations.Comment: 24 pages, 1 figure. Corresponds to journal versio
Modules for Experiments in Stellar Astrophysics (MESA)
Stellar physics and evolution calculations enable a broad range of research
in astrophysics. Modules for Experiments in Stellar Astrophysics (MESA) is a
suite of open source libraries for a wide range of applications in
computational stellar astrophysics. A newly designed 1-D stellar evolution
module, MESA star, combines many of the numerical and physics modules for
simulations of a wide range of stellar evolution scenarios ranging from
very-low mass to massive stars, including advanced evolutionary phases. MESA
star solves the fully coupled structure and composition equations
simultaneously. It uses adaptive mesh refinement and sophisticated timestep
controls, and supports shared memory parallelism based on OpenMP. Independently
usable modules provide equation of state, opacity, nuclear reaction rates, and
atmosphere boundary conditions. Each module is constructed as a separate
Fortran 95 library with its own public interface. Examples include comparisons
to other codes and show evolutionary tracks of very low mass stars, brown
dwarfs, and gas giant planets; the complete evolution of a 1 Msun star from the
pre-main sequence to a cooling white dwarf; the Solar sound speed profile; the
evolution of intermediate mass stars through the thermal pulses on the He-shell
burning AGB phase; the interior structure of slowly pulsating B Stars and Beta
Cepheids; evolutionary tracks of massive stars from the pre-main sequence to
the onset of core collapse; stars undergoing Roche lobe overflow; and accretion
onto a neutron star. Instructions for downloading and installing MESA can be
found on the project web site (http://mesa.sourceforge.net/).Comment: 110 pages, 39 figures; submitted to ApJS; visit the MESA website at
http://mesa.sourceforge.ne
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