quantopian algorithms

"Reprint please indicate the source" Chenrudan.github.io Recently looked at some things about the dimensionality reduction algorithm, this article first gives out seven kinds of algorithms of an information table, this paper sums up the parameters of each algorithm, the main purpose of the algorithm and so on, and then introduces some basic concepts of dimensionality reduction, including what is the dimension of dimensionality reduction, why dimension

Issues such as coordination, asynchronous behavior, responsiveness, and scalability can be the focus of attention in concurrent space. These are some of the more esoteric topics that developers must consider when designing applications. However, perhaps due to inexperience or lack of proper performance tools, some equally important topics are often overlooked. A high-performance algorithm is one example. At the enterprise level, developers carefully weigh issues such as distributed file systems

calculation. MD5 use Prevent tampering: For example, send an electronic document, before sending, I get MD5 output result a. After receiving the electronic document, the other party also gets a MD5 output B. If A and B are the same, the middle is not tampered with. For example, I provide file download, in order to prevent the illegal elements in the installation program to add Trojan, I can publish on the website by the installation files

the last one; Repeat steps until the sort is complete. 1.2 Motion Diagram Demo1.3 Code implementation1 /** 2 * Bubble sort 3 * 4 * @param array 5 * @return 6 * /7 public static int[] Bubblesort (int[] Array) {8 if (Array.Length = = 0) 9 return array;10 for (int i = 0; i 1.4Algorithm AnalysisBest case: t (n) = O (n) worst case: t (n) = O (n2) Average condition: t (n) = O (n2)2. Select sort (Selection sort)One of the most stable s

may be less (personal sense, not confirmed) for comparison-based sorting algorithms.Back to the topic, now analyze the stability of the common sorting algorithms, each giving a simple reason.(1) Bubble sortThe bubble sort is to move the small element forward or the large element back. is a comparison of two adjacent elements , and the interchange also occurs between these two elements. So, if the two elements are equal without exchanging positions, a

process is as follows:4. Copying algorithms Compared with the tag-purge algorithm, the replication algorithm is a relatively efficient recovery method Not suitable for situations where there are many surviving objects, such as the old age Divide the original memory space into two pieces, using only one piece at a time During garbage collection, the surviving objects in the memory being used are copied to the unused block o

The first blog has implemented three most basic and simple sorting algorithms, and this article will evolve slightly based on these three algorithms.1. Quick-Linelight from the name to know the speed is certainly not bad, the previous story of the bubble sort, how to see is not a good sort of algorithm, filled with too much unnecessary exchange action, time complexity is very stable O (n^2), but it is not j

Java implementation of several large sorting algorithms Update in ... Note: This class is accompanied by a random generation [min, max) range of non-repeating integers, if you crossing any better suggestions for this method, welcome to communicate. The ideas of each algorithm are written in this class of comments, but also convenient for you to verify the local environment. The currently completed sorting

Stanford Algorithms (a): Multiply by large number (C + +)Just not in the Chinese university Mooc attended the course of Chen teacher 数据结构 , Harvest very big. Feel the strike, also put the algorithm part also to a school, on the Coursera registered a Stanford University algorithm class, the amount of the course is very heavy, estimated to learn a semester, slowly learn, steady.The course recommended a lot of books, I found a book, the title is called

. MD is the abbreviation of message Digest algorithm, Chinese name Messages Digest algorithm, the latest fifth edition is MD5, the historical version of MD4, MD2, etc., due to the existence of defects are no longer used. The result of the message digest algorithm is different between versions. The MD2 algorithm was produced in 1989;The MD4 algorithm was produced in 1990;The MD5 algorithm was generated in 1991. MD5 is a widely used version, but its security has been questioned ma

sorting algorithms are more common: bubble sort, simple selection sort, direct insert sort, hill sort, heap sort, merge sort and fast sort algorithm, etc. Learn the first three simple algorithms today. Related concepts of sorting:① the stability of the sort: two or more elements are equal, and the order is still the same, and the ordering is stable.② internal ordering: The sorting process is done in memory

Various cryptographic algorithms for JavaJava provides us with a wealth of encryption technology, can be basically divided into one-way encryption and asymmetric encryption1. One-way encryption algorithmOne-way encryption algorithm is mainly used to verify the data transmission process, whether it has been tampered with. BASE64 strictly speaking, it belongs to the encoding format, not the encryption algorithm MD5 (Message Digest algorithm

The internal sorting algorithm mainly divides into the order of inserting class, the sort of exchange class and the sort of choice class, and their performance difference is mainly embodied in time complexity, space complexity and stability. Various sorting algorithms will be compared and moved between elements, the time complexity is mainly determined by the number of comparisons and the number of moves in the whole sorting process. Space complexity

1. Random algorithm:the load balancing method randomly assigns the load to each available server, selects a server by the random number generation algorithm, and sends the connection to it. the same request will fall to machine A, a will fall on machine B, the cache will be frequently eliminated, so that the cache hit rate is low. 2. Polling algorithm:The polling algorithm assigns each new connection request to the next server in order, eventually splitting all requests to all servers. Polling

Summarization of algorithms for moving target detection and tracking process Image preprocessingSome typical noises in digital images are: Gaussian noise comes from the noise of electronic circuit and low illumination or high temperature. The salt and pepper noise is similar to that of pepper and salt powder randomly distributed on the image, which is caused by the image cutting and the error caused by the transform domain; additive

Divide and conquer algorithm I. Basic CONCEPTS In computer science, the partition method is a very important algorithm. The literal explanation is "divide and conquer", which is to divide a complex problem into two or more identical or similar child problems, and then the problem is divided into smaller sub problems ... Until the last child problem can be simply solved directly, the solution of the original problem is the merging of the solution of the child problem. This technique is the basis

Learned so many sorting algorithms, has not done a summary, hehe Bubble SortBubble sort is the slowest sort algorithm. In practical use it is the least efficient algorithm. It compares each element of the array by a Bandi and makes the larger data sink and the smaller data rise. It is an O (n^2) algorithm. Quick SortThe quick sort is an in-place sequencing, divide-and-conquer, large-scale recursive algorithm. Essentially, it is the in-place version o

Dr. Christoph Koutschan of the Austrian Institute for Symbolic Computing (research Institute for symbolic Computation, RISC) published an article on his own page, referring to a survey he did Most of the participants were computer scientists who asked the scientists to vote on the most important algorithms, following the results of the survey, sorted alphabetically by English name: 1, A * search algorithm-graphics search algorithm, from the given sta

Introduction Nowadays, the data of all kinds of information system is more and more large, how to transfer and store data faster and more is the primary problem of data processing, and data compressing technology is an important method to solve this problem. In fact, data compression technology has long been applied in various fields, from the compression software winrar to the familiar MP3. 2 Data compression Technology Overview In essence, the data is compressed because the data itself is r

 1. Select sort, quick sort, hill sort, heap sort not a stable sorting algorithm, Bubble sort, insert sort, merge sort, and Cardinal sort are stable sorting algorithms. 2. What is the significance of studying the stability of sequencing algorithms? First of all, the stability of the sorting algorithm should be known, popularly speaking is to ensure that the first two of the same sort of data in the seque