Speed up gf(eye(x)) a.k.a. Speed up Galois field creation for sparse matrices

From the documentation (communications toolbox)

x_gf = gf(x,m) creates a Galois field array from the matrix x. The Galois field has 2^m elements, where m is an integer between 1 and 16.

Fine. The effort for big matrices grows with the number of elements of x. No surprise, as every element must be "touched" at some point.

Unfortunately, this means that the costs of gf(eye(n)) throw quadratically with n. Is there a way to profit from all the zeros in there?

PS: I need this to delete a row from a gf-Matrix, as the usual m(:c)= [] way does not work, and my idea of multiplying a gf-matrix with a cut unity matrix was surprisingly slow..


I don't have this toolbox, but maybe gf supports sparse-data inputs, which could drastically reduce your execution time in such a case.

Need Your Help

@Transactional not working with spring and hibernate

hibernate spring transactions annotations

I am trying to do spring transactions with @Transactional without any success.

How do I Create an HTTP Request Manually in .Net?

.net http webclient

I'd like to create my own custom HTTP requests. The WebClient class is very cool, but it creates the HTTP requests automatically. I'm thinking I need to create a network connection to the web ser...

About UNIX Resources Network

Original, collect and organize Developers related documents, information and materials, contains jQuery, Html, CSS, MySQL, .NET, ASP.NET, SQL, objective-c, iPhone, Ruby on Rails, C, SQL Server, Ruby, Arrays, Regex, ASP.NET MVC, WPF, XML, Ajax, DataBase, and so on.