Parallel and Concurrent Programming in Haskell

As one of the developers of the Glasgow Haskell Compiler (GHC) for almost 15 years, I have seen Haskell grow from a niche research language into a rich and thriving ecosystem. I spent a lot of that time working on GHC’s support for parallelism and concurrency. One of the first things I did to GHC in 1997 was to rewrite its runtime system, and a key decision we made at that time was to build concurrency right into the core of the system rather than making it an optional extra or an add-on library. I like to think this decision was founded upon shrewd foresight, but in reality it had as much to do with the fact that we found a way to reduce the overhead of concurrency to near zero (previously it had been on the order of 2%; we’ve always been performance-obsessed). Nevertheless, having concurrency be non-optional meant that it was always a first-class part of the implementation, and I’m sure that this decision was instrumental in bringing about GHC’s solid and lightning-fast concurrency support.

Haskell has a long tradition of being associated with parallelism. To name just a few of the projects, there was the pH variant of Haskell derived from the Id language, which was designed for parallelism, the GUM system for running parallel Haskell programs on multiple machines in a cluster, and the GRiP system: a complete computer architecture designed for running parallel functional programs. All of these happened well before the current multicore revolution, and the problem was that this was the time when Moore’s law was still giving us ever-faster computers. Parallelism was difficult to achieve, and didn’t seem worth the effort when ordinary computers were getting exponentially faster.

Around 2004, we decided to build a parallel implementation of the GHC runtime system for running on shared memory multiprocessors, something that had not been done before. This was just before the multicore revolution. Multiprocessor machines were fairly common, but multicores were still around the corner. Again, I’d like to think the decision to tackle parallelism at this point was enlightened foresight, but it had more to do with the fact that building a shared-memory parallel implementation was an interesting research problem and sounded like fun. Haskell’s purity was essential—it meant that we could avoid some of the overheads of locking in the runtime system and garbage collector, which in turn meant that we could reduce the overhead of using parallelism to a low-single-digit percentage. Nevertheless, it took more research, a rewrite of the scheduler, and a new parallel garbage collector before the implementation was really usable and able to speed up a wide range of programs. The paper I presented at the International Conference on Functional Programming (ICFP) in 2009 marked the turning point from an interesting prototype into a usable tool.

All of this research and implementation was great fun, but good-quality resources for teaching programmers how to use parallelism and concurrency in Haskell were conspicuously absent. Over the last couple of years, I was fortunate to have had the opportunity to teach two summer school courses on parallel and concurrent programming in Haskell: one at the Central European Functional Programming (CEFP) 2011 summer school in Budapest, and the other the CEA/EDF/INRIA 2012 Summer School at Cadarache in the south of France. In preparing the materials for these courses, I had an excuse to write some in-depth tutorial matter for the first time, and to start collecting good illustrative examples. After the 2012 summer school I had about 100 pages of tutorial, and thanks to prodding from one or two people (see the Acknowledgments), I decided to turn it into a book. At the time, I thought I was about 50% done, but in fact it was probably closer to 25%. There’s a lot to say! I hope you enjoy the results.

Audience

You will need a working knowledge of Haskell, which is not covered in this book. For that, a good place to start is an introductory book such as Real World Haskell (O’Reilly), Programming in Haskell (Cambridge University Press), Learn You a Haskell for Great Good! (No Starch Press), or Haskell: The Craft of Functional Programming (Addison-Wesley).

How to Read This Book

The main goal of the book is to get you programming competently with Parallel and Concurrent Haskell. However, as you probably know by now, learning about programming is not something you can do by reading a book alone. This is why the book is deliberately practical: There are lots of examples that you can run, play with, and extend. Some of the chapters have suggestions for exercises you can try out to get familiar with the topics covered in that chapter, and I strongly recommend that you either try a few of these, or code up some of your own ideas.

As we explore the topics in the book, I won’t shy away from pointing out pitfalls and parts of the system that aren’t perfect. Haskell has been evolving for over 20 years but is moving faster today than at any point in the past. So we’ll encounter inconsistencies and parts that are less polished than others. Some of the topics covered by the book are very recent developments: Chapters 4, 5, 6, and pass:[14 cover frameworks that were developed in the last few years.

The book consists of two mostly independent parts: Part I and Part II. You should feel free to start with either part, or to flip between them (i.e., read them concurrently!). There is only one dependency between the two parts: Chapter 13 will make more sense if you have read Part I first, and in particular before reading “The ParIO monad”, you should have read Chapter 4.

While the two parts are mostly independent from each other, the chapters should be read sequentially within each part. This isn’t a reference book; it contains running examples and themes that are developed across multiple chapters.

No comments, shop8admin, July 26, 2017

Petrochemical plant construction is expected to hit imports

Director General of the Ministry of Industry, Manufacturing Industry, Panggah Susanto said, with the new petrochemical plant planned to be built in West Papua is expected to reduce the number of Indonesian imports of raw materials.

“These projects will be able to reduce the importation of raw materials which, according to the data in 2012 reached 16 billion U.S. dollars for chemical raw materials,” said Panggah after witnessing the signing of the MoU between Ferrostaal Industrial Projects by PT Chandra Asri Petrochemical Tbk, in Jakarta on Thursday.

He said that with the cooperation will be produced basic products, such as propylene and polypropylene, which will not reduce the importation of raw materials.

“Hopefully, in 2019 to be operational, which we seek is how as soon as possible to get gas allocation,” he said.

Panggah explain step construction of the plant is part of the Ministry of Industry to develop two important sectors in Indonesia related to the chemical industry base and base metals.

“Two of the basic industries we encourage its development, it is important because it aligned with the growth of domestic industry, which will increase the need for raw materials and capital goods,” he said.

He said later that the results of the plant is expected to require an investment of $ 1.8 billion will be earmarked for the domestic market.

“Domestic demand is big enough, then it will be destined for the domestic market,” he said.

No comments, shop8admin, July 26, 2017

What If My Hosting Company Doesnt Back Up My Website

What if my hosting company doesnt back up my website?

The security of your website is a fragile issue. At least one website is being hacked in every 5 seconds. This rate is quite alarming. Not only this, sometimes, you yourself can make a mess with your database and other resources while making any change to web design in New York and wish hard that you had backed up your data on a prior basis. However, people usually pick the backup system provided by the hosting company as this is the most convenient method for website backups. online hosting review

However, there are a good number of hosting companies that do not let you enjoy the backup system for free or even if they do the system does not allow you to access individual files or databases. In most of the cases, you would not really want to get a complete backup as probably the previous backup has almost everything and all you want is to get the new updates that have been made. In that scenario, probably your New York web design firm can help you by introducing you to the Joomla CMS and easy to use Joomla backup plugins. For example, by using a plugin like Sypex Dumper you can let the plugin decide if there is any change in the database and the plugin itself will decide whether any backup is needed or not. web hosting reviews

Hosting Reviews Online is a staff of web hosting experts who cover a longtime experience in reviewing web hosting websites. The basic idea to establish our site online is to help the webmasters in making the right decision when it comes to choose the web hosting company. This site is a complete guide to every consumer who wants to get complete knowledge about web hosting products and services of a company so that they can launch their business online with ease.

No comments, shop8admin, July 26, 2017

Picking Out 22013 Fall Evening Dress Styles And Designs

You can choose beautiful evening gowns in different colors, styles, patterns and designs, it is an important thing to find right one. Since party gown, cocktail dresses, formal wear, and even prom dresses all make glamour evening party dresses, the best way to find a evening dress style is often to simply start with you.

Selecting a dress based on your personality and body type often makes more sense than choosing one based on trends or arbitrary dress style rules and guidelines. 2013 Evening dress styles are extremely diverse, so look for one thats a reflection of you.

Trumpet/mermaid Skirts.
Trumpet skirts are the toned-down version of the mermaid skirt thats been extremely popular the last several years. Mermaid skirts arent diverse enough to stand the test of time for many women, but trumpet skirts are stepping up to take their place with a similar but more diverse style. Trumpet skirts are easier to move and dance in, and offer a slightly less flashy and more elegant look, making them appealing to more women.

Sweetheart Neckline
The sweetheart neckline is a look thats been trendy for decades and isnt going to disappear anytime soon. This simple and elegant bodice works well with a range of body types. It helps large-breasted women contain their bust while giving small-breasted women a bust boost. This cut can be combined with practically any skirt waistline, making it a winning combination every time.

One Shoulder
One shoulder gowns are very trendy right now, but theyre not for everyone. This style is back with a vengeance from the late 70s and early 80s, but with a little more elegance this time around. Single strap dresses offer a unique look for women who want to make an impression. While the strap has some restrictions on the type of neckline a dress will have, it can be combined with any skirt style. One look that blends well with the solo strap is a low- to no-back dress, which can be very elegant and sexy.

High-low Style
This popular and distinct style has something to offer anyone and is perfect for the dress shopper on a budget or for a woman in need of a dress for multiple occasions. This diverse skirt style gives you two dress options in one: a short skirt for semi-formal events, and a long skirt for more formal occasions that still lets a woman show a little (or a lot) of leg.

Sequins, Rhinestones, and Glitter
One way to dress up a fairly simple dress style is by adding some glam and sequin. Once considered over-the-top and gaudy, flashy sequins, rhinestones, and fabric glitter have come a long way and now add a touch of elegance to an evening gown instead. If you prefer blacks and whites or muted colors over loud, bold ones, consider wearing a dress with a little sequin decoration to take it to the next level of formality and style.

No comments, shop8admin, July 26, 2017

China City Tour give you a goog holiday

is always my dream. If I want to achieve my dream, I must visit the famous Chinese cities one by one. China is a rich country in culture and history, and it is also the birth place of a kind of civilization in the world. A complete China city tour should take you to enjoy the Chinese cultural cities and Chinese historical cities. Beijing is the first choice, as it is the capital of China and capitals in ancient China. Beijing city tour covers various attractions, so Beijing tour is hard to achieve. If any possible, I would visit the Great Wall, Forbidden City, Summer Palace, etc. They are the represents of Beijing and ancient Beijing. Yangtze River is the mother of Chinese, as it is also the birth place of Yangtze River civilization. Along with Yangtze River, there were various minorities and civilizations, but some of had lost during the development of social. Yangtze River Cruise gives you a chance to seek the footprints of these lost civilizations. From Yichang to Chongqing, you must have big harvest, especially the Three Gorges. Huangshan is the base of Taoism in Chinese, has many vestiges of famous people like poem, Taoists, swordsman, etc. Nowadays, the Huangshan has become a famous tourists scenic spot in China, attracts large number of tourists from all over the world every year. Huangshan tour also becomes hotter among China city tours, takes you to visit many historical and characteristic spots nearby Huangshan Mountain. It is one of the stops in my China trips. Guilin, famous all over China with its beautiful mountain and rivers, attracts me lots. Like me, there are various travelers want to enjoy the elegant demeanour of Guilin. Guilin tour is listed in my plans as the must-see place. Like Elephant Trunk Hill, Reed Flute Cave, Li River, you would not find any similar spots in other places. In China, you can list many cities with characteristic spots and sceneries. Just need your enthusiasm, and you can have a wonderful and knowledgeable China tour, such as Yunnan tour, Zhangjiajie tour, Xian tour, etc. In addition, if you have any trouble in China tour, you can book these tours on BeijingLandscapes.com, it will give you best help and advices. Even they can tailor your tours according to your needs and demands. Trust it, you will have satisfied China city tour. Have good time!

No comments, shop8admin, July 26, 2017

Bakrie and Brothers Profit Drops So Rp 8.3 Billion

Net income of PT Bakrie and Brothers Tbk (Bakrie) fell dramatically during the first half of 2013 to only Rp 8.36 billion. In fact, in the same period of the previous year the company was pocketing a profit of Rp 214.35 billion.

President Director of Bakrie and Brothers Bobby Gafur Umar stated, profit drop due to the divestment of a subsidiary Bakrie Petroleum International Pte in 2012. It, which makes the company’s revenues come eroded.

During the period January-June 2013 pesebesar company posted revenue of Rp 1.95 trillion, down from the acquisition of the first half of 2012 which reached Rp 11.39 trillion. “This is due to the deconsolidation of a subsidiary of Bakrie Petroleum us,” he said in a written statement on Wednesday, July 31, 2013.

The largest revenue contribution came from the company’s subsidiary in the manufacturing sector. Bakrie Building Industries opens Rp 380.73 billion in revenue, up 23 percent compared to the same period last year. Net income also rose 73 percent, or Rp 45.82 billion.

Bakrie Pipe Industries, which manufactures pipes also recorded a positive performance during the first semester of 2013. “Bakrie Pipe Revenue rose to Rp 751.92 billion from Rp 700.55 billion.’s Net profit also rose 102 percent from Rp 32.75 billion to Rp 66.22 billion,” said Bobby.

Boobby continued throughout the first six months of this year the management company managed to cut interest expenses and finance up to 78 percent or Rp 603 billion from Rp 775.79 billion in the first half of 2012 menjajdi Rp 172.78 billion in the first semester of 2013. “We will continue to depress spending and increase business efficiency,” he said

No comments, shop8admin, July 26, 2017

Online Forex Trading What It Is And How Does It Work

A large number of people are trying to discover methods to earn extra cash. Though, an individual may find various online jobs, nonetheless, they cant earn a lot of money with such jobs, which are more of a part time nature. But now its possible through forex trade online, which provides a scope of quitting the previous job and starting a lucrative career for those armed with proper knowledge, technique and skills.

If you are interested in forex trading, then you can get started without much hassle. Nothing can be more effective and convenient than trading in forex market, that too from the comfort of your home. Nonetheless, it doesnt mean that its a simple job. Trading in forex market is no laughing matter. Only, people with good trading skills, market knowledge, discipline and dedication can do it. In order to earn money via this method you need a reliable and trusted training source.

Forex market is a marketplace where currency exchanges take place. Trading of United State dollar against British currency is one of the best examples. This way, one can easily make transactions in other nations. As some of you might know, this concept has been around for years but individuals have to visit currency exchange stations or banks to exchange their currency. With the introduction of forex trading systems online, you no longer have to go to currency exchange stations, plus you can earn a decent amount as well.

The trading platforms also offer demonstrations that can simulate a trading situation in the marketplace. Before actually trying the real thing, an individual must try these demonstrations, which are the best way to gather information about how trading happens. These demonstrations will help you learn . Online forex trading is usually performed by trading platforms. Here, one can get training, support and background information on the foreign exchange market. You can also get an expert advice, from proficient traders who share their experience and knowledge about forex trading, thus assuring an individual of support, whenever needed.

Though, it involves risk, but if you trade carefully, the risk is low. You need to employ the most appropriate forex broker over the internet in order to ensure that you earn a steady amount. Also, when trading on your own, consult experts to get signals on when to purchase/sell and trade. Then there are experts who charge some fee to provide the tips and basics of foreign exchange trading. The only thing you need to do is to find reliable and trustworthy experts and advisors who have outstanding track records in .

If an individual owns the right tools and knows how the market works, he can easily learn forex trading and earn a lot of money.

No comments, shop8admin, July 26, 2017

Cake tasting Traditional Home Business

Business inspiration can come from anywhere as long as there is a will. Aspects of local traditions can be used as capital to start a business while keeping the local culture.

For example, a typical cake Gorontalo is trying maintained by a home-based entrepreneur from Gorontalo cake that had long settled in Jakarta, which named Mona Melani Djamal.

One typical food is the most favored Gorontalo boat cake, cakes made from brown sugar major, coconut milk, coconut slices, and given the pandan Dauh container shaped like a boat.

“Make cakes Gorontalo Gorontalo not accidentally let the cake is gone,” said Mona to the Editor (13/06/2011).

According to the raw materials to make this cake is fairly easy to come by because of the brown sugar until the coconut milk can be found in almost every market, both modern markets and traditional markets. But Mona admitted it is not easy to make a cake batter that was not damaged boat. He always tries to make a cake with the perfect boat.

“It took a struggle that wanted to make, should not be left ditungguin. Continues to make the container can not nyuruh people, not animating can not neat,” he said.

According to Mona, this boat cake introduced by his close friends when gathering. Currently, he has been marketing his boat pastries to out of town, even to his hometown in Gorontalo. Mona’s experience, can be an inspiration how memesarkan products cake home from the neighborhood market up to a wider audience.

“Used to love divided if there gathering. Continues know word of mouth is the only boat I make cakes. Now that mesen already everywhere as it may be sparse. Already nyampe everywhere to me, I never send pesenan Gorontalo to send aircraft use, “he explained.

Mona explains the capital to make a boat cake is fairly cheap. To make the cake as much as 50 boats, Mona only spent less than Rp 50,000. Hargsa only one slice of cake boat priced Rp 2,500. Mona claims often gets skewed comments from customers, but Mona seldom bother because it’s the price to pay to enjoy a boat patience in baking.

“Sometimes people say expensive, but people say what’s up deh.’s Expensive services,” he said.

Mona added, as this type of cake is rarely sold because he took this opportunity to meet their daily needs.

“Sometimes people say expensive, but people say what’s up deh.’s Expensive services,” he said.

By selling cookies boat, he was able to generate more than USD 3 million in a month, it also depends on the order came because Mona is only selling the boat cake if there are orders from customers.

“Not necessarily because tergangtung order, usually above Rp 3 million per month. Makes pesenan only if there is no sale actually” he said.

In addition to boat cake Mona also sell some cakes Gorontalo others, such as Sirikaya Fuel, How to Fill, Wapili. In addition to boat cake, Mona also serve
such order another cake and custard eclairs.

No comments, shop8admin, July 26, 2017

Sql Server Database Corruption If You Run A Query With Parallel Execution Plan

You may come across Access Violation if you run an SQL query, which uses parallel execution plan in Microsoft SQL Server 2008. Access violation is an error condition, which may occur while performing general operations on the SQL database. It may occur due to application malfunction, software bug, or database corruption. It renders your database inaccessible and may cause data loss, if you don’t have a complete backup to restore data from. To overcome such issues, is required.

As an example of Access Violation in Microsoft SQL Server 2008, consider the below scenario:

In MS SQL Server 2008, you’re running a query that includes all the below mentioned clauses:
Inner join
Union all
Group by
The database query is using parallel execution plan.
You execute the query.

In the above scenario, you may face access violation. And, you receive the following error message:

Location: xbmp.cpp:2038
Expression: 0 != pxteBitmap
Msg 3624, Level 20, State 1, Line 2
A system assertion check has failed. Check the SQL Server error log for details. Typically, an assertion failure is caused by a software bug or data corruption. To check for database corruption, consider running DBCC CHECKDB. If you agreed to send dumps to Microsoft during setup, a mini dump will be sent to Microsoft. An update might be available from Microsoft in the latest Service Pack or in a QFE from Technical Support.
Msg 0, Level 20, State 0, Line 0
A severe error occurred on the current command. The results, if any, should be discarded.

Furthermore, the mini-dump file is returned under the log folder of MS SQL Server 2008.

Cause

As sated in the above error message, this problem may have occurred due to either database corruption or a software bug. After corruption, SQL Server can not read the database and this behavior occurs.

Resolution

Run DBCC CHECKDB utility to try fixing database corruption. If the database is severely corrupted, it may not work. In such cases, third-party applications are worth using.

The MS SQL Recovery applications are particularly designed to thoroughly scan whole SQL Server database and extract all damaged and inaccessible objects from it. They allow you to perform SQL Recovery on your own as they have simple and rich graphical user interface.

SQL Recovery software safely and successfully repairs damaged SQL Server database in all cases of corruption. It works well with Microsoft SQL Server 2008, 2005, and 2000. The software restores all database objects such as tables, reports, forms, macros, and more.

No comments, shop8admin, July 26, 2017

Dave the Funky Shoulder Monkey – The Most Popular Toy This Christmas

Dave the Funky Shoulder Monkey is quite simply a toy monkey that sits on your shoulder, but there is far more to this new electronic ape than meets the eye. Many toy stores have been searching for the next toy craze. Last year it was Zhu Zhu Pets that took the world by storm, this year it looks like a cute little black and white monkey called Dave is going to be the next huge hit. Read on to find out what sets Dave the Funky Shoulder Monkey apart from the huge array of children’s toys on the market this Christmas and why he will be in such demand.

A team of toy developers in the UK invented this cuddly robot monkey; little did they know at the time how popular he would turn out to be! He has already been named by major toy retailers in the UK, Toys R Us and Hamleys, as one of the top sellers this Christmas and there has also been significant interest from Toys R Us in the United States.

The Dave the Funky Shoulder Monkey design is based on a real-life Capuchin monkey and he can be attached to clothing by means of a shoulder strap so he is able to perch jauntily on your shoulder without falling off. His movements, sounds and mannerisms are operated using a small cordless remote control that can easily be concealed in the hand or in your pocket. Thanks to some clever and sophisticated micro-robotics, this cheeky monkey can display a realistic range of sounds and behaviours just like a real monkey and this is what makes him stand out from many of the other robot pet toys on the market.

Dave the Funky Shoulder Monkey has several different modes accessed using various buttons on the simple to operate remote control, including Conversation Mode, Greeting Mode, Puppet Mode and Action Mode. Each mode offers a different range of characteristics and behaviours – he can laugh, cry, burp, fart, wave and even, being a monkey, scratch himself. This makes him the centre of attention, who can resist the sight of an unusual monkey sat on someone’s shoulder waving and farting! His realistic sounds and movements are a source of fascination and hilarity for children and adults alike and this is why Dave the Cheeky Monkey will be the number one toy this Christmas.

This interactive monkey toy has become so sought after that the manufacturers have had to open another factory in an attempt to keep up with demand from toy stores. Make sure you buy Dave the Funky Shoulder Monkey early to avoid disappointment!

No comments, shop8admin, July 26, 2017



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