Must have valid initData to build channel

I have a parallel Matlab of 56 workers, I get the following error as I increase the upper (end) value of the parfor loop.

"Must have valid initData to build channel"

Can you please help me to solve this problem

Thanks

[Edric Ellis]

This is an internal consistency error and definitely not expected - do you have any reproduction steps that you can post?

Answer 1

[Halil Eyyuboglu]

Thanks for the reply. I get the error message, "Must have valid initData to build channel" I run the code below

-------------------------------------------------------------------------------------------------------------

patd = 'C:\PhaseFluctuations_Data\Paper_data\DataSLmV1L01km_Dmat200';

Psmat = load(patd,'-mat');Psmat = Psmat.Psmaty;Psmat = imag(Psmat);

iatla = 201;nreals = 2000;nreals = 50;%PsL01 = [];

parfor is = 1:nreals

PsL01(:,:,is) = Psmat(iatla*(is -1) + 1:is*iatla,1:iatla);

end

---------------------------------------------------------------------------------------------------------------------------

Notes

1) Error does not occur, if "nreals" = 10, but error occurs when "nreals" is changed to 50 or higher.

2) Psmat is a matrix of 402000 x 200 elements and the loop attempts to rearrange this matrix into 200 x 200 x 2000

3) No error is generated if "for" is used instead of "parfor"

Answer 2

[Edric Ellis]

I expect this is a misleading error as a consequence of running out of memory on the workers. You're duplicating Psmat and attempting to put a full copy of it on each of your 56 workers. (By restricting nreals, you're limiting the number of workers used).

I doubt this sort of manipulation is a good fit for parfor in any case. You might be better off doing:

permute(reshape(Psmat.', 200, 200, 2000), [2 1 3])

or something similar. Here's my vastly-simplified example:

>> data = [ 1, 2; 3, 4; 11, 12; 13, 14; 101, 102; 103, 104]
data =
     1     2
     3     4
    11    12
    13    14
   101   102
   103   104
>> permute(reshape(data.', 2, 2, 3), [2 1 3])
ans(:,:,1) =
     1     2
     3     4
ans(:,:,2) =
    11    12
    13    14
ans(:,:,3) =
   101   102
   103   104

Answer 3

[Halil Eyyuboglu]

Thanks, this solves my problem.