View License

Download apps, toolboxes, and other File Exchange content using Add-On Explorer in MATLAB.

» Watch video

Highlights from

Be the first to rate this file! 2 Downloads (last 30 days) File Size: 34.6 KB File ID: #30764 Version: 1.2




15 Mar 2011 (Updated )

Do: C = frontal_mtimes(A, b); not: for k=1:size(A,3), C(:,:,k) = A(:,:,k) * b(:,:,k); end

| Watch this File

File Information

These routines assist in the manipulation of matrices with same shape but different content. For example, performing the product A*b is trivial for matrix A and vector b, but what would you do if you had several such products to form? Examples abound: rotations, Jacobians, covariances, etc. Using the frontal routines, you'd collect them all in a three-dimensional matrix or third-order tensor, with each k-th frontal panel of A(:,:,k) and b(:,:,k) storing one such a related matrix and vector. Then calling

  C = frontal_mtimes(A, b);

would do the equivalent of

  for k=1:size(A,3), C(:,:,k) = A(:,:,k) * b(:,:,k); end

but using internally different algorithms depending on the dimensions of A (including a C-mex option). If you like operator overloading, you can do instead:

  A = frontal(A);
  b = frontal(b);
  C = A*b;

You might want to compile the file frontal_mtimes_helper.c, but it's not required.

After you've unzipped it, test your installation running:


(don't do addpath(genpath('c:\work\fx\frontal\frontal\')))


Testit, Multiple Matrix Multiplications, With Array Expansion Enabled, and Mtimesx Fast Matrix Multiply With Multi Dimensional Support inspired this file.

MATLAB release MATLAB 7.9 (R2009b)
Tags for This File   Please login to tag files.
Please login to add a comment or rating.
Comments and Ratings (4)
16 Mar 2011 Felipe G. Nievinski

Don't do:




as instructed.

Comment only
16 Mar 2011 James Tursa

James Tursa (view profile)

OK. I think I have it working now, at least partially. I had to add both the frontal directory *and* the util subdirectory to the path.

Comment only
16 Mar 2011 Felipe G. Nievinski

Please check your unzipping procedure. I've double checked the zip and the directory structure is intact.

Comment only
16 Mar 2011 James Tursa

James Tursa (view profile)

FYI: From the "Other Files" display above it looks like the intent is to install this as a class directory structure with some helper files. But when the zip file is downloaded there is no such directory structure. All I get is a bunch of files. So I will have to manually build the @frontal folder and then separate out the helper functions also, maybe putting them in a private directory under @frontal. Is it your intent that a person who downloads this has to build all these directory structures manually?

Comment only
16 Mar 2011 1.1

clarified paths

16 Apr 2011 1.2

added acknowledgements; applied more tags.

Contact us