These instructions let you write apps that can do complex image calculations quickly while placing less stress on mobile devices’ batteries than if you were to use general purpose instructions. VImage gives you a way to manipulate large images using the CPU’s vector instruction set. All the libraries work similarly, and the vImage library provides clear visual examples that will be easier to understand than more complex tasks like digital signal processing. In this tutorial, you’ll explore the Accelerate framework using the vImage library. Because Apple uses these frameworks extensively, you’ll also find support on all current Apple platforms.
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The archive and compression frameworks also build on top of Accelerate. For example, CoreML builds on top of BNNS. Sparse Solvers, BLAS and LAPACK: for linear algebra calculationsĪpple also uses these libraries as building blocks of other frameworks.vForce: to perform arithmetic and transcendental calculations on large sets of numbers.vDSP: a library of digital signal processing functions.BNNS: for training and running neural networks.So before diving into code, take a look at the components of Accelerate.Īccelerate comprises several related libraries, each of which performs a dedicated type of mathematical process.
You need to first understand a bit about what Accelerate is and the components that you will use in this tutorial. It uses the vector-processing capabilities on modern purpose-built CPUs to perform calculations quickly while maintaining efficient energy usage. The Accelerate framework gives app developers an efficient, high-speed library for large-scale mathematical or image-based calculations. This increased ability invites programmers to add more complicated calculations to these devices, increasing the utility of a phone. Today, a phone can do calculations in a fraction of a second that once would have taken a team of people weeks or even months. Early computers existed almost exclusively to automate tedious and error-prone calculations previously done by hand. We only scratched the surface in this post.The most valuable benefit of modern computing might be the ability to do complicated math quickly and accurately. I encourage you to explore the documentation of DateFormatter to explore the other options this class has to offer. Let string = " 29 October 2019 20:15:55 +0200"ĭateFormatter.dateFormat = "dd MMM yyyy HH:mm:ss Z"ĭateFormatter.date(from: string) // at 7:15 PM The DateFormatter class supports more complex date formats than the one we explored earlier. The return type is of type String?, an optional.
This means that you should never forced unwrap the value returned by the date(from:) method. In the eyes of the date formatter, the string that is passed to the date(from:) method is invalid. The date format of the string that is passed to date(from:) method is MM/dd/yy while the dateFormat property has a value of dd/MM/yy. Can you spot the mistake? import Foundation If the string you pass to the date formatter doesn't match the date format of the date formatter, then date(from:) returns nil. You always need to be careful when using the date(from:) method of the DateFormatter class. The value you assign to the dateFormat property needs to conform to UTS or Unicode Technical Standard. The dateFormat property is of type String. Let's set the dateFormat property of the DateFormatter instance and give it another try. It cannot infer the date format of the string. The DateFormatter is powerful, but it isn't magical. We passed a string to the date formatter's date(from:) method without specifying the date format of the string. The method seems to work fine since we don't see any errors or warnings. To convert the string to a date, we pass it to the date(from:) method of the DateFormatter class. We create a DateFormatter instance to convert the string to a date. I show you a more advanced example later in this post. Let's define the string we plan to convert to a Date object. This means we add an import statement for Foundation at the top of the playground. Fire up Xcode and create a playground.Īs I mentioned in the introduction, the DateFormatter class is defined in the Foundation framework. The class we use to convert a string to a date in Swift is DateFormatter (or NSDateFormatter if you are using Objective-C). The Foundation framework makes it painless to convert a string to a date, but there are a few pitfalls you need to watch out for.
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