Packjpg options trading
This is the extent of what the module provides. Use absolute positioning, background positions, canvas, generate a static image on the backend, whatever you like! My favorite is the fullWidthBreakoutRowCadence option that we use on album pages. All config options are documented on the docs and demo page. The justified layout algorithm is just one part of our photo list infrastructure. We welcome your feedback, issues and contributions on Github.
This is the first of quite a bit of code we have in the works for open source release. When working with large-scale software systems, configuration management becomes crucial; supporting non-uniform environments gets greatly simplified if you decouple code from configuration. Popular approaches to solving this problem include using configuration files or having a dedicated configuration service. Our new solution combines the extremely popular GitHub and cfg4j library, giving you a very flexible approach that will work with applications of any size.
Configuration repository and editor: Where your configuration lives. Intermediary store that we use to improve fetch speed and to ease load on GitHub servers. Continuous deployment pipeline pushing changes from repository to push cache, and validating config correctness. Fetches configs from push cache and exposing them to your business logic. The first thing you might expect from the configuration repository and editor is ease of use.
So what options are out there that may satisfy those requirements? Git provides us with a history of changes and an easy way to branch off configuration.
It also has great support in the form of GitHub which we use both as an editor built-in support for YAML files and collaboration tool pull requests, forks, review tool. Both are nicely glued together by following the Git flow branching model. One of the goals was to make managing multiple configuration sets execution environments a breeze. We need the ability to add and remove environments quickly.
For every environment, we store a separate directory with config files in Git. All of them have the exact same structure and only differ in YAML file contents. This solution makes working with environments simple and comes in very handy during local development or new production fleet rollout see use cases at the end of this article.
Some of the products that we work with at Yahoo have a very granular architecture with hundreds of micro-services working together. It greatly reduces the overhead of maintaining multiple repositories. We support this use case by having multiple top-level directories, each holding configurations for one service only. The main role of push cache is to decrease the load put on the GitHub server and improve configuration fetch time. Since speed is the only concern here, we decided to keep the push cache simple: You can install Consul clients on the edge nodes and they will keep being synchronized across the fleet.
This greatly improves both the reliability and the performance of the system. If performance is not a concern, any key-value store will do. You can skip using push cache altogether and connect directly to Github, which comes in handy during development see use cases to learn more about this.
When the configuration repository is updated, a CD pipeline kicks in. This fetches configuration, converts it into a more optimized format, and pushes it to cache. Before we can connect to the push cache to fetch configuration, we need to know where it is. The config contains the hostname, port to connect to, and the name of the environment to use. You need to put this config with your code or as part of the CD pipeline.
This simple yaml file binding Spring profiles to different Consul hosts suffices for our needs:. The configuration library takes care of fetching the configuration from push cache and exposing it to your business logic.
This library re-loads configurations from the push cache every few seconds and injects them into configuration objects that our code uses. It also takes care of local caching, merging properties from different repositories, and falling back to user-provided defaults when necessary read more at http: The most important piece is business logic.
To best make use of a configuration service, the business logic has to be able to re-configure itself in runtime. Here are a few rules of thumb and code samples: When you develop a feature, a main concern is the ability to evolve your code quickly.
A full configuration-management pipeline is not conducive to this. We use the following approaches when doing local development: When you work with multiple environments, some of them may share a configuration. Configuration repository, push cache, and configuration CD pipeline can experience outages. Verifying that code and configuration are kept in sync happens at the configuration CD pipeline level. One part of the continuous deployment process deploys the code into a temporary execution environment, and points it to the branch that contains the configuration changes.
Once the service is up, we execute a batch of functional tests to verify configuration correctness. The presented solution is the result of work that we put into building huge-scale photo-serving services. We needed a simple, yet flexible, configuration management system. Combining Git , Github , Consul and cfg4j provided a very satisfactory solution that we encourage you to try. I want to thank the following people for reviewing this article: To help improve the search ranking and relevance of national, personal, and religious holiday photos, we first have to see when the photos were taken; when, for example, is the Christmas season?
Understanding what people are looking for when they search for their own photos is an important part of improving Flickr.
We did this a total of times. These might include a year , a month January , a season winter , or a holiday or special event Thanksgiving, Eid al-Fitr, Easter, Passover, Burning Man. So we wanted to understand that situation: To answer this, we mapped We expect this may reflect antipodean seasons: For example, if it snows the day after Thanksgiving, it definitely feels like winter.
Not all temporal search terms are quite so complicated; some holidays are celebrated and photographed on a single day each year, like Canada Day July 1st or Boxing Day December 26th. While these holidays can be easily translated to date queries, other holidays have more complicated temporal patterns. Have a look at these lunar holidays.
These events move around in a regular, algorithmically determinable, but sometimes complicated, way. Most of these holidays tend to oscillate as a leap calculation is added periodically to synchronize the lunar timing to the solar calendar. Some holidays and events, like birthdays, happen on every day of the week. So to get back to our original question: If you look at other languages, this difference practically goes away: But Christmas photos are taken throughout December.
We can now set a threshold for a definition of Christmas: That means that every day from December 1st to January 1st hits that definition, with December 2nd barely scraping in. That makes…32 days of Christmas! Merry Christmas and Happy Holidays —for all the holidays you celebrate and photograph. In the last couple of months, Apple has released new features as part of iOS 9 that allow a deeper integration between apps and the operating system.
Here at Flickr, we have added support for these new features and we have learned a few lessons that we would love to share. There are two different kinds of content that can be searched through Spotlight: To explicitly index content, you use Core Spotlight, which lets you index multiple items at once. NSUserActivity also allows us to mark certain items as public, which means that they might be shown to other iOS users as well.
For a better user experience, we index as much useful information as we can right off the bat. Indexing an item looks like this:. Since we have multiple kinds of data — photos, albums, and groups — we had to create an identifier that is a combination of its type and its actual model ID.
Flickr provides a huge amount of public content, including many amazing photos. For this public content — photos, public groups, tags and so on — we leverage NSUserActivity, with its new search APIs, to make it all searchable when viewed.
Every time a user opens a photo, public group, location page, etc. The more often a specific activity is made current, the more relevant iOS considers it.
This is a JSON file that describes which relative paths in your domains can be handled by the app. When a user taps a link from another app in iOS, if your app is able to handle that domain for a specific path, it will open your app and call application: If the only intent is to support Universal Links, no further steps are required. In Flickr, we have a few different domains. That means that each one of flickr. In our case, the flic.
On the client side, only a few steps are required to support Universal Links. Here is how it looks for Flickr:. Now if someone receives a text message with a Flickr link, she will jump right to the Flickr app when she taps on it. Now we just have to get the user to the proper place within the app.
There are different entry points into our app, and we need to make the implementation consistent and avoid code duplication. To support deep linking, apps could register to handle custom URLs meaning a custom scheme, such as myscheme: The website corresponding to the app could then publish links directly to the app.
For every custom URL published on the Flickr website, our app translates it into a representation of the data to be shown. This representation looks like this:. As for NSUserActivity objects passed into application: One arises when the NSUserActivity instance was used to index a public item in the app. This is really handy because it not only uniquely identifies the data we want to present, but also gives us a NSURL object, which we can handle the same way we handle deep links or Universal Links.
We need to parse the identifier we created for the item and translate it into a FLKRoute. We can decompose it and then create our route object. Its simplified implementation looks like this:. The final application delegate method looks like this:. One of the coolest features it has brought is the ability to preview content before pushing it onto the navigation stack. You can easily see how this feature is implemented in the native Mail app. If the user taps on a photo in one of these cells, it will open the photo view.
Previews of these UIViewControllers should be shown accordingly. That view is then responsible for returning the model used to populate the UIViewController that the user is trying to preview. This is how this logic looks:. Last but not least, we added support for Quick Actions. Now the user has the ability to quickly jump into a specific section of the app just by pressing down on the app icon. Defining these Quick Actions statically in the Info. Finally, we have to handle where to take the user after she selects one of these options.
This is yet another place where we can make use of our FLKRoute object. To handle the app opening from a Quick Action, we need to implement application: There is a lot more to consider when shipping these features with an app.
For example, with Flickr, there are various platforms the user could be using. It is important to make sure that the Spotlight index is up to date to reflect changes made anywhere.
That requires some considerations around threading and network priorities. Network requests for UI-relevant data should not be blocked because we have other network requests happening at the same time.
Finally, we had to consider privacy, one of the pillars of Flickr. In order to focus on those features, we simplified some of our examples to demonstrate how you could get started with them in your own app, and to show what challenges we faced. Have a love of online photography? Want to work with us? Find out more at flickr.
At Flickr our users really care about image quality. They also care a lot about how responsive our apps are. Slow transfers are especially noticeable on mobile devices.
JPEG compression has several tuneable knobs. With a setting of 4: JPEG stored at different quality and chroma levels. The upper left image is saved at high quality and chroma level; notice the color and detail in the folds of the red flag.
This compression ratio is highly dependent on image content and dimensions. The compressed images were smaller and nearly indistinguishable from their sources. To really evaluate this technology had to use a better measure of perceptibility: Users accumulate points the longer they play, and get more points for doing well at the game.
We maintained a leaderboard to encourage participation and used only internal testers. The images came from a variety of cameras and included a number of subjects from photographers with varying skill levels.
A sampling of images used in our taste test. In each round, our test code randomly select a test image, and present two variants of this image side by side. We randomly swap the location of the compressed images to compensate for user bias to the left or the right. If testers choose correctly, they are presented with a second question: Screenshot of taste test. Our test displays images simultaneously to prevent testers noticing a longer load time for the larger, non-compressed image.
The images are presented with either , , or pixels on their longest side. The intent behind this detail is to represent how real users interact with our images. The px images stay on screen for 20 seconds, as we expect larger images to be viewed for longer periods of time by real users.
We award points per round, regardless of whether a tester chose correctly and also award a bonus of points when a tester correctly identifies whether images were identical or different. We ran our taste test for two weeks and analyzed our results. We disregarded users that had fewer than eleven results. When our testers were presented with two identical images, they thought the images were identical only Our image pairs were so similar that multiple testers thought all images were identical and reported that the test system was buggy.
We inspected the images most often labeled different, and found no significant artifacts in the compressed versions. This was a best-case scenario for us.
This marked the first time Flickr had adjusted image settings in years, and, it was fun. Taste test high score list. We had run a taste test on this newer setting and users were were able to spot our compression slightly more often than with our original settings. When presented a pair of identical images, our testers declared these images identical Boy were we wrong! The Flickr Help Forum had a very lively thread which Petapixel picked up.
Conclusion We have described our system for large-scale visual similarity search at Flickr. The Cost Story A little back-of-the-envelope math shows storage costs are a real concern. Adjusting Storage Thresholds As we dug into the problem, we looked at our storage systems in detail. Adjusting storage thresholds Extending Existing Approaches In our earlier posts, we have described dynamic generation of thumbnail sizes and perceptual compression.
Decreasing the number of thumbnail sizes Lossless JPG Compression Flickr has had a long-standing commitment to keeping uploaded images byte-for-byte intact. Ask users what topics interest them Ask users why they joined a particular group Implicit: Infer user tastes from groups they join, photos they like, and users they follow Infer why users joined a particular group based on their activity, interactions, and dwell time Feedback: Given a user, return a list of recommended groups Use Case 3: Given a photo, return a list of groups that the photo could belong to Collaborative Filtering One approach to recommender systems is presenting similar content in the current context of actions.
Users hate to see the same results being offered even though they might be relevant. We require a good threshold that balances similarity and diversity. To improve diversity further, we combine recommendations from different algorithms. Users expect their interactions to have a quick effect on recommendations.
We thus incorporate user interactions while making subsequent recommendations so that the system feels dynamic. Recommendation results are cached so that API response is quick on subsequent visits. Cold Start The drawback to collaborative filtering is that it cannot offer recommendations to new users who do not have any associations.
Measuring Effectiveness We use qualitative feedback from user studies and alpha group testing to understand user expectation and to guide initial feature design. Have you ever tried coding on a plane? Tightly coupled with superagent. Difficult to specify the full HTTP response. What happens if the API changes the response schema?
The client makes an actual HTTP request. If VCR has a tape matching the request, it simply replays the response to the client. Otherwise, VCR lets the HTTP request through to the service, records the interaction to a new tape on disk and plays it back to the client. Open Source at Flickr This is the first of quite a bit of code we have in the works for open source release. Why should I decouple configuration from the code? Faster configuration changes e. Configuration can simply be injected without requiring parts of your code to be reloaded and re-executed.
Config-only updates tend to be faster than code deployment. Different configuration for different environments: Running your app on a laptop or in a test environment requires a different set of settings than production instance. All these players work as a team to provide an end-to-end configuration management solution. Configuration repository and editor The first thing you might expect from the configuration repository and editor is ease of use.
Configuration should be easy to read and write. It should be straightforward to add a new configuration set. You most certainly want to be able to review changes if your team is bigger than one person. Support from popular IDEs — freedom of choice is priceless. Multi-tenancy support optional is often pragmatic. Push cache The main role of push cache is to decrease the load put on the GitHub server and improve configuration fetch time.
Bootstrap configuration Before we can connect to the push cache to fetch configuration, we need to know where it is. This simple yaml file binding Spring profiles to different Consul hosts suffices for our needs: Configuration library The configuration library takes care of fetching the configuration from push cache and exposing it to your business logic. Fallback and merge strategies: Simplifies local development and provides support for multiple configuration repositories.
Integration with Dependency Injection containers — because we love DI! Configurable code The most important piece is business logic. Use dependency injection for injecting configuration.
Common use-cases applying our simple solution Configuration during development local overrides When you develop a feature, a main concern is the ability to evolve your code quickly. By making your local file a primary configuration source, you provide an override mechanism. If the property is found in your file, it will be used. If not, cfg4j will fall back to using values from configuration store.
Set up your private push cache, point your service to the cache, and edit values in it directly. Configuration defaults When you work with multiple environments, some of them may share a configuration.
Dealing with outages Configuration repository, push cache, and configuration CD pipeline can experience outages. Keeping code and configuration in sync Verifying that code and configuration are kept in sync happens at the configuration CD pipeline level.
Summary The presented solution is the result of work that we put into building huge-scale photo-serving services. Spotlight Search There are two different kinds of content that can be searched through Spotlight: There are basically two ways in which you can sell options contracts. First, if you have previously bought contracts and wish to realize your profits, or cut your losses, then you would sell them by placing a sell to close order.
The order is named as such because you are closing your position by selling options contracts. You would usually use that order if the options you owned had gone up in value and you wanted to take your profits at that point, or if the options you owned had fallen in value and you wanted to exit your position before incurring any other losses. The other way you can sell options is by opening a short position and short selling them. This is also known as writing options, because the process actually involves you writing new contracts to be sold in the market.
When you do this you are taking on the obligation in the contract i. Writing options is done by using the sell to open order, and you would receive a payment at the time of placing such an order. This is generally riskier than trading through buying and then selling, but there are profits to be made if you know what you are doing. You would usually place such an order if you believed the relevant underlying security would not move in such a way that the holder would be able to exercise their option for a profit.
For example, if you believed that a particular stock was going to either remain static or fall in value, then you could choose to write and sell call options based on that stock. You would be liable to potential losses if the stock did go up in value, but if it failed to do so by the time the options expired you would keep the payment you received for writing them.
Options traders tend to make their profits through the buying, selling, and writing of options rather than ever actually exercising them. However, depending on the strategies you are using and the reasons you have bought certain contracts, there may be occasions when you choose to exercise your options to buy or sell the underlying security.
The simple fact that you can potentially make money out of exercising as well as buying and selling them further serves to illustrate just how much flexibility and versatility this form of trading offers. What really makes trading options such an interesting way to invest is the ability to create options spreads.
You can certainly make money trading by buying options and then selling them if you make a profit, but it's the spreads that are the seriously powerful tools in trading. A spread is quite simply when you enter a position on two or more options contracts based on the same underlying security; for example, buying options on a specific stock and also writing contracts on the same stock. There are many different types of spreads that you can create, and they can be used for many different reasons.
Most commonly, they are used to either limit the risk involved with taking a position or reducing the financial outlay required with taking a position. Most options trading strategies involve the use of spreads. Some strategies can be very complicated, but there are also a number of fairly basic strategies that are easy to understand.
You can read more about all the different types of spreads here. There are actually a number of benefits this form of trading offers, plus the versatility that we have referred to above. It's continuing to grow in popularity, not just with professional traders but also with more casual traders as well. To find out just what it is that makes it so appealing, please read the next page in this section — Why Trade Options?
What is Options Trading? Section Contents Quick Links. What Does Options Trading Involve? Below we explain in more detail all the various processes involved. Buying Options Buying an options contract is in practice no different to buying stock.
Exercising Options Options traders tend to make their profits through the buying, selling, and writing of options rather than ever actually exercising them.
Options Spreads What really makes trading options such an interesting way to invest is the ability to create options spreads. Benefits of Trading Options There are actually a number of benefits this form of trading offers, plus the versatility that we have referred to above. Read Review Visit Broker.