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The Cholesky decomposition is a method to decompose an hermitean, positiv definite matrix into an upper triangular matrix and its transpose. It can be used to solve linear equations systems and and is around twice as fast as LU-decomposition. A = [4 12 -16 12 37 -43 -16 -43 98]; R = chol...

This method will decompose a matrix into an upper triangular and an orthogonal matrix. A = [4 12 -16 12 37 -43 -16 -43 98]; R = qr(A); This will return the upper triangular matrix while the following will return both matrices. [Q,R] = qr(A); The following plot will display the run...

Hereby a matrix will be decomposed into an upper trangular and an lower triangular matrix. Often it will be used to increase the performance and stability (if it's done with permutation) of Gauß elimination. However, quite often does this method not or badly work as it is not stable. For example A...

Why do we need this? The current way to do unit testing in Xamarin.Forms is via a platform runner, so your test will have to run within an ios, android, windows or mac UI environment : Running Tests in the IDE Xamarin also provides awesome UI testing with the Xamarin.TestCloud offering, but when ...

The CompareValidator control compares a value in one control with a fixed value or a value in another control. It has the following specific properties: PropertiesDescriptionTypeIt specifies the data type.ControlToCompareIt specifies the value of the input control to compare with.ValueToCompareIt ...

Say, you have a dataset consisting of names and email addresses. Now in another dataset, you just have the email address and wish to find the appropriate first name that belongs to that email address. The MATCH function returns the appropriate row the email is at, and the INDEX function selects i...

If you are attempting to get an Angular2 site running on your Windows work computer at XYZ MegaCorp the chances are that you are having problems getting through the company proxy. There are (at least) two package managers that need to get through the proxy: NPM Typings For NPM you need to ad...

@Component @Lazy public class Demo { .... .... } @Component public class B { @Autowired @Lazy // If this is not here, Demo will still get eagerly instantiated to satisfy this request. private Demo demo; ....... }

Allow change user unique ID if account is compromised with a new user&password login To invalidate tokens when user changes their password or permissions, sign the token with a hash of those fields. If any of these field change, any previous tokens automatically fail to verify. The down...

If you want to use docker for rails app, and use database, you need to know that all the data in the docker container will be destroyed (unless you configure the container specifically for keeping data) Sometimes, you need to create a docker container with an application and attach it to an old con...

One of most common use cases of Gitflow Initialize repo and define branches $ git flow init # if you use default setup, you'll define six types of branches: # # main branches (lives forever) # # 1. master: for production releases # 2. develop: for "next ...

You cannot access any GUI components from the BackgroudWorker. For example if you try to do something like this Private Sub BackgroundWorker1_DoWork(sender As Object, e As DoWorkEventArgs) TextBox1.Text = "Done" End Sub you will receive a runtime error saying that "Cross-thr...

<Exec Command="echo Hello World" />

In order to enable writing more complex UI tests the UIAutomatorViewer is needed. The tool located at /tools/ makes a fullscreen screenshot including the layouts of the currently displayed views. See the subsequent picture to get an idea of what is shown: For the UI tests we are looking for resou...

The next example is intended to count the amount of flags in the specified flag combination. The example is provided as a extension method: <DebuggerStepThrough> <Extension> <EditorBrowsable(EditorBrowsableState.Always)> Public Function CountFlags(ByVal sender As [Enum]) As In...

Use the tar (tape archive) command to compress your files and folders. It is similar to creating .ZIP files in Windows environment. Syntax: tar -zcvf <output tar file> <source file> Example: tar -zcvf outputfile.tar.gz source file Here’s what those switches actually mean: -c: Cr...

The best way to install and configure a Symfony2 project is described in the official documentation as follows: Mac OS X / Linux $ sudo curl -LsS http://symfony.com/installer -o /usr/local/bin/symfony $ sudo chmod a+x /usr/local/bin/symfony Windows c:\> php -r "file_put_contents('sym...

When you have entered something into IEx which expects a completion, such as a multiline string, IEx will change the prompt to indicate that it is waiting for you finish by changing the prompt to have an ellipsis (...) rather than iex. If you find that IEx is waiting for you to finish an expression...

Lets say you want to filter a query by two columns, but only certain combinations of those columns. For example, it's OK to have account 60400 with reference JE, but you cannot have account 60400 with reference ED, but you can have account 60500 with reference ED. select * from schema.table where ...

WRITE record COMMIT