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Parfor problem --- "Array construction from ByteBuffer Threw an exception"

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Hi! I run my code using the 'parfor' function BUT receive an error message:
  • Array construction from ByteBuffer Threw an exception.
I am wondering what does this message mean in simple language? Any simple example could be great!
Thanks for your help!
Walter Roberson
Walter Roberson on 21 Jul 2021
"I want to separate table records into different groups (in cells) based on the value of a variable (e.g., "varname_a"),"
G = findgroups(varname_a) ;
Tablename_cell = splitapply(@(x) {x}, Tablensme, G);
Jiashun Wu
Jiashun Wu on 25 Jul 2021
@Walter Roberson Thanks again for your note.
My aim is to use 'parfor' to help separate my table into sub-groups, without imposing any summary statistics. In other words, somewhere like improving the code in
Anyway, I have already improved my code for better efficiency while keeping a tradtional 'for' approach.

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Accepted Answer

Alvaro on 1 Dec 2022
Edited: Alvaro on 1 Dec 2022
The following code runs with no issues in my version of MATLAB R2022b.
load patients
% Create test table
Tablename = table(Gender(1:5), Height(1:5), 'VariableNames', {'Gender', 'Height'});
clearvars -except Tablename
Tablename_Cell = {};
K = table(unique(Tablename.Gender), ...
'VariableNames', {'Gender'});
A_number = 2;
parfor i = 1:A_number
Tablename_Cell{i} = Tablename(find(strcmp(Tablename.Gender, K.Gender(i))),:);
% Some other codes afterwards --- But even just keep the code
% above would receive the error message "Array construction
% from ByteBuffer Threw an exception."
I did switch from using == to strcmp since I got the error
Operator '==' is not supported for operands of type 'cell'.
but I believe everything else is the same. Consider trying Bowei's suggestion of using a for loop with a dummy table to determine whether parfor is the cause of the issue.
I would also take another look at the documentation that you linked
Functions like splitapply already include parallelization as part of their extended capabilities.

More Answers (1)

Bowei Li
Bowei Li on 18 Aug 2022
Hi, I run into this error when using parfor as well. I found there was a undefined variable in my parfor loop. To check it, you may change your parfor to for, run it, and see what it says.


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