Passing variables to functions with variable length input arguments

Question

blkdiag uses varargin to construct a block diagonal matrix from the input arguments (each matrix which needs to be inserted into the diagonal).

out = blkdiag(a,b,c,d,...), where a, b, c, d, ... are matrices, outputs a block diagonal matrix of the form

Suppose I had a cell array of matrices (or some other data structure) ; how would I feed this to a function like blkdiag?

It does however give good information to people looking for help on SO. — Phonon
– Phonon, Commented Oct 31, 2011 at 19:45
@Jacob: I disagree. I think it's perfectly ok to post a good answer to your own question. — Jonas
– Jonas, Commented Oct 31, 2011 at 19:53
@Jonas: Yep, definitely, but I personally prefer to do it if my answer is better/remains unanswered. — Jacob
– Jacob, Commented Oct 31, 2011 at 23:17

Bee · Accepted Answer · 2011-10-31 20:35:10Z

3

Use {:} to expand it for the function:

blocks = cell(2);
blocks{1} = rand(2);
blocks{2} = rand(2);
out = blkdiag(blocks{:})

Answer:

out =

0.6787    0.7431         0         0
0.7577    0.3922         0         0
     0         0    0.6555    0.7060
     0         0    0.1712    0.0318

answered Oct 31, 2011 at 20:35

Bee

2,51221 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Passing variables to functions with variable length input arguments

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related