Applying array of transform matrices to array of vectors

I have a large array of 3x3 transform matrices, e.g. 3x3x700 that I would like to apply to a corresponding array of 3x1 vectors e.g. 3x1x700 to obtain an array of transformed vectors. Is there a way of vectorising this operation that is more efficient than using a for loop?

Thanks,

Steve

Answer 1

[Paul]

Check out pagemtimes. Whether or not it's faster than a loop ... would need to be tested on your system

D = rand(3,3,700);
v = rand(3,1,700);

tic,y = pagemtimes(D,v);toc

Elapsed time is 0.005295 seconds.

z = 0*y;
tic
for ii = 1:700
    z(:,1,ii) = D(:,:,ii)*v(:,1,ii);
end
toc

Elapsed time is 0.006762 seconds.

isequal(z,y)

ans = logical
   1

[Stephen Hubbard]

That's great, thank you. On my system your code takes 327 us for pagemtimes compared with 2435 us for the for loop.