The inverse of the gradient function. I ve provided versions that work on 1-d vectors, or 2-d or 3-d arrays. In the 1-d case I offer 5 different methods, from cumtrapz, and an integrated cubic spline, plus several Finite difference methods.
In higher dimensions, only a Finite difference/linear algebra solution is provided, but it is fully vectorized and fully sparse in its approach. In 2-d and 3-d, if the gradients are inconsistent, then a least squares solution is generated
非線性有限元程序，NONSAP is a general Finite element program for the nonlinear static and dynamic analysis of complex structures. The program is very flexible and was designed to be extended and modified by the user. In particular the program can easily be modified to use a different formulation of the equations of motions, different time integration operators and other additional options.
C 開發(fā)的有限元軟件，界面還可以，不錯(cuò)，可以試試。 FElt is a free system for introductory level Finite element analysis. It is
primarily intended as a teaching tool for introductory type courses in Finite
elements - probably in the mechanical/structural/civil fields. In a command
line environment, FElt uses an intuitive, straightforward input syntax to
describe problems. It also includes a graphical user interface for
workstations that allows the user to set-up, solve and post-process the
problem in a single CAD-like environment.
密碼學(xué)界牛人Victor Shoup用C++編寫數(shù)論類庫(kù)。
NTL is a high-performance, portable C++ library providing data structures and algorithms for arbitrary length integers for vectors, matrices, and polynomials over the integers and over Finite fields and for arbitrary precision floating point arithmetic.
NTL provides high quality implementations of state-of-the-art algorithms for:
* arbitrary length integer arithmetic and arbitrary precision floating point arithmetic
* polynomial arithmetic over the integers and Finite fields including basic arithmetic, polynomial factorization, irreducibility testing, computation of minimal polynomials, traces, norms, and more
* lattice basis reduction, including very robust and fast implementations of Schnorr-Euchner, block Korkin-Zolotarev reduction, and the new Schnorr-Horner pruning heuristic for block Korkin-Zolotarev
* basic linear algebra over the integers, Finite fields, and arbitrary precision floating point numbers.
It was proposed that perfect invisibility cloaks can be constructed for hiding objects from electromagnetic
illumination (Pendry et al., Science 312, p. 1780). The cylindrical cloaks experimentally
demonstrated (Schurig et al., Science 314, p. 997) and theoretically proposed (Cai et al., Nat. Photon.
1, p. 224) have however simplified material parameters in order to facilitate easier realization
as well as to avoid infinities in optical constants. Here we show that the cylindrical cloaks with
simplified material parameters inherently allow the zeroth-order cylindrical wave to pass through
the cloak as if the cloak is made of a homogeneous isotropic medium, and thus visible. To all
high-order cylindrical waves, our numerical simulation suggests that the simplified cloak inherits
some properties of the ideal cloak, but Finite scatterings exist.
This thesis is devoted to several efficient VLSI architecture design issues in errorcorrecting
coding, including Finite field arithmetic, (Generalized) Low-Density Parity-
Check (LDPC) codes, and Reed-Solomon codes.
The 2D CFD Program NaSt2D
The program is a 2D solver for the incompressible, transient Navier-Stokes equations including the temperature equation and free boundary problems. It uses Finite differences for discretization on a structured equidistant staggered grid, central and upwind (donor-cell) discretization of the convective parts and an explicit time stepping scheme. The free boundary value problems are treated with the MAC technique.
Compression using lempel-ziv
-for a dictionary size of 2k
-provide dictionary
Lempel ziv algorithm is a dictionary based algorithm that addresses byte sequences from former contents instead of the original data. This algorithm consists of a rule for parsing strings of symbols from a Finite alphabet into substrings, whose lengths do not exceed a prescribed integer and a coding scheme which maps these substrings sequentially into uniquely decipherable code words of fixed length. The strings are selected so that they have nearly equal probability of occurrence. Frequently-occurring symbols are grouped into longer strings while occasional symbols appear in short strings.
This application note considers the design of frequency-
selective filters, which modify the frequency content
and phase of input signals according to some specification.
Two classes of frequency-selective digital filters
are considered: inFinite impulse response (IIR) and Finite
impulse response (FIR) filters. The design process
consists of determining the coefficients of the IIR or FIR
filters, which results in the desired magnitude and
phase response being closely approximated.
This application note considers the design of frequency-
selective filters, which modify the frequency content
and phase of input signals according to some specification.
Two classes of frequency-selective digital filters
are considered: inFinite impulse response (IIR) and Finite
impulse response (FIR) filters. The design process
consists of determining the coefficients of the IIR or FIR
filters, which results in the desired magnitude and
phase response being closely approximated.
