Computing and the way people use C for doing it keeps changing as years go by. So overwhelming has been the response to all the previous editions of “Let Us C” that I have now decided that each year I would come up with a new edition of it so that I can keep the readers abreast with the way C is being used at that point in time.
This book has existed (in one form or another) since the first edition of C# and the .NET Platform
was published in conjunction with the release of .NET 1.0 Beta 2, circa the summer of 2001. Since
that point, I have been extremely happy and grateful to see that this text was very well received by
the press and, most important, by readers. Over the years it was nominated as a Jolt Award finalist
(I lost . . . crap!) and for the 2003 Referenceware Excellence Award in the programming book category
Implementation of GPU (Graphics Processing Unit) that rendered triangle based models. Our goal was to generate complex models with a movable camera. We wanted to be able to render complex images that consisted of hundreds to thousands of triangles. We wanted to apply interpolated shading on the objects, so that they appeared more
smooth and realisitc, and to have a camera that orbitted around the object, which allowed us to
look arond the object with a stationary light source. We chose to do this in hardware, because our initial implementation using running software on the NIOS II processor was too slow. Implementing parallelism in hardware is also easier to do than in software, which allows for more efficiency. We used Professor Land s floating point hardware, which allowed us to do calculations efficiency, which is essential to graphics.
matlab有限元網格劃分程序
DistMesh is a simple MATLAB code for generation of unstructured triangular and tetrahedral meshes. It was developed by Per-Olof Persson (now at UC Berkeley) and Gilbert Strang in the Department of Mathematics at MIT. A detailed description of the program is provided in our SIAM Review paper, see documentation below.
One reason that the code is short and simple is that the geometries are specified by Signed Distance Functions. These give the shortest distance from any point in space to the boundary of the domain. The sign is negative inside the region and positive outside. A simple example is the unit circle in 2-D, which has the distance function d=r-1, where r is the distance from the origin. For more complicated geometries the distance function can be computed by interpolation between values on a grid, a common representation for level set methods.
For the actual mesh generation, DistMesh uses the Delaunay triangulation routine in MATLAB and tries to optimize the node locations by a force-based smoothing procedure. The topology is regularly updated by Delaunay. The boundary points are only allowed to move tangentially to the boundary by projections using the distance function. This iterative procedure typically results in very well-shaped meshes.
Our aim with this code is simplicity, so that everyone can understand the code and modify it according to their needs. The code is not entirely robust (that is, it might not terminate and return a well-shaped mesh), and it is relatively slow. However, our current research shows that these issues can be resolved in an optimized C++ code, and we believe our simple MATLAB code is important for demonstration of the underlying principles.
To use the code, simply download it from below and run it from MATLAB. For a quick demonstration, type "meshdemo2d" or "meshdemond". For more details see the documentation.
《分析性寫作》，介紹言簡意賅：
The popular, brief rhetoric that treats writing as thinking, WRITING ANALYTICALLY, Sixth Edition, offers a series of prompts that lead you through the process of analysis and synthesis and help you to generate original and well-developed ideas. The book's overall point is that learning to write well means learning to use writing as a way of thinking well. To that end, the strategies of this book describe thinking skills that employ writing. As you will see, this book treats writing as a tool of thought--a means of undertaking sustained acts of inquiry and reflection.
VIP+ is support software for YAMAHA RCX series robot controllers. In addition to the functions
of the previously released "VIP Windows" software, VIP+ includes an easy-to-use GUI (graphical
user interface). VIP+ also allows control by 2 or more controllers or access to a controller from
2 or more clients via Ethernet connection.
● With VIP+ you can:
? Do offline editing of all data used on robot controllers
? Operate and monitor robots connected to robot controllers
? Do online editing of all data used with robot controllers
? Back up and restore robot controller data
● Functions and features newly added to VIP+:
? Ethernet connection to controllers
? Supports data input in spreadsheet software format
? Seamless backup and restoring of controller information such as point data
? Syntax coloring
? Data transfer between the online controller and an offline document by drag & drop
? Executes online commands using a terminal window
? Controller tree and document tree functions similar to Windows Explorer
We introduce a sub-cell WENO reconstruction method to evaluate spatial derivatives in the high-order ADER scheme. The basic idea in our reconstruction is to use only r stencils to reconstruct the point-wise values of solutions and spatial derivatives for the 2r-1 th order
ADER scheme in one dimension, while in two dimensions, the dimension-by-dimension sub-cell reconstruction approach for spatial derivatives is employed. Compared with the original ADER scheme of Toro and Titarev (2002) [2] that uses the direct derivatives of reconstructed polynomials for solutions to evaluate spatial derivatives, our method not only reduces greatly the computational costs of the ADER scheme on a given mesh,
but also avoids possible numerical oscillations near discontinuities, as demonstrated by a number of one- and two-dimensional numerical tests. All these tests show that the 5th-order ADER scheme based on our sub-cell reconstruction method achieves the desired accuracy, and is essentially non-oscillatory and computationally cheaper for problems with discontinuities.
The goal of the present document is to give a starting point for people newly
interested in R. I chose to emphasize on the understanding of how R works,
with the aim of a beginner, rather than expert use.
