To convert a variable (struct with fields of numeric matrix) to a sliced variable (an array of struct)

I was doing code refactor to apply parfor to some legacy code. Legacy code creates a big struct variable called 'Boot', with fields of numeric matrix.

I want to convert it to a new sliced variable "BootS" , but if I do the conversion like the attached image, Matlab give me warnings that I should preallocate it.

( iters means number of iterations.)

I tried to preallocate BootS as the code commented out , it fails with runtime errors.

Anyone has good idea to convert it elegantly??

[Edric Ellis]

There are a few possible failure modes here - please could you post a self-contained example that fails when using parfor. I tried the following in R2018b, and it worked fine, so I'm missing something:

iters = 10;
clear BootS;
BootS(iters) = struct();
parfor i = 1:iters
    BootS(i).PD.sim = rand();
    BootS(i).PDOS.sim = rand();
end

(I also presume you're doing some computationally intensive work in the parfor loop - simply reformatting data in this way using parfor is highly unlikely to gain you any performance advantage)

[Owen Zhang]

thank you, i got it.. there is no runtime error with your code.

(in this loop, i just want to convert the data from Boot to Boots, a new sliced variable. Boot is not a sliced variable , can't be used in parfor.)

but with runtime error by creating a function returning the struct..

but anyway , i see how to do it now.

iters = 10;
clear Boots; 
Boots(iters) = struct();

for i=1:iters
    Boots(i) = genOneStruct();
end

Answer 1

[Owen Zhang]

closed

see answer above