# Weird behavior for pagemrdivide matlab 2022b vs 2022a

10 views (last 30 days)
Adam on 21 Dec 2022
Commented: Heiko Weichelt on 19 Jan 2023
I am noticing some strange behaviour when using pagemrdivide. When I run the code below, the Dpage variable contains a lot of NaN, while the Dfor variable computes just fine. I expect these two to be equal, but they are not. Has anyone else encountered this behaviour before?
When I run the same code in matlab 2022a, I don't get this behaviour, it seems to be introduced in 2022b.
F = 300;
D = randn(2,2,F) + 1i*randn(2,2,F);
P = [0 0 1 0
1 0 0 0
0 0 0 1
0 -1 0 0];
P11 = P(1:2,1:2);
P12 = P(1:2,3:4);
P21 = P(3:4,1:2);
P22 = P(3:4,3:4);
Dpage = pagemrdivide(pagemtimes(P11,D) + P12, pagemtimes(P21,D)+P22);
Dfor = zeros(size(D));
for ff = 1 : F
Dfor(:,:,ff) = mrdivide(P11*D(:,:,ff)+P12,P21*D(:,:,ff)+P22);
end
nnz(isnan(Dpage))
ans = 600
nnz(isnan(Dfor))
ans = 0
Heiko Weichelt on 19 Jan 2023
EBR is online:
As mentioned before, R2022b Update 4, which will be released in a few days, will contain the fix.

Adam Danz on 18 Jan 2023
Edited: Adam Danz on 18 Jan 2023
Be on the lookout for the next update (update 4) to MATLAB R2022b.
3 Ways to check for MATLAB Updates
1. From MATLAB Desktop, go to the home tab and select the dropdown menu under Help, then select "Check for Updates".
2. Look for a red bell in the upper right corner of the desktop (it's gray when there are no available updates). Click it.
Heiko Weichelt on 19 Jan 2023
I was not aware of this but GPU code is separate and not my expertise. I'll poke some of my colleagues about it. Thanks.

### Categories

Find more on Data Type Identification in Help Center and File Exchange

R2022b

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!