parfeval or batch processing

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Muna Tageldin
Muna Tageldin 2020-11-2
编辑： Muna Tageldin 2020-11-3
Assuming I want to convert the below code from using parpool to using parcluster. The problem with my code is that the for loop is 10,000 iterations (I get an error in running the code ), however when I run with 100 iterations, the code runs well). It seems the problem is with waiting time for future objects ( I increased the waiting time from 10,000 to 30,000).
The error is "Error using parallel.FEvalFuture/fetchNext. The function completed with an error. Caused by: no workers available for FevalQueue excution.
I figured I should try batch processing following this question and also parcluster as I am running the code on a remote cluster.
My question is how do I share files (function file) to the workers on the clusters ? do I need to pass constants to workers like in parallel.pool.constant. Also, what's the difference between using batch processing and parfeval ?
poolobj=parpool('my_cluster',8);
[up, op]=ndgri(1e-3:1e-2:1,1e-3:1e-2:1);
up=reshape(up, [1,size(up,1)*size(up,2)]);
up=reshape(up, [1,size(up,1)*size(up,2)]);
z=rand(5,5e3);
addAttachedFiles('<path to my function/cores_random.m');%%to add the function files to workers on the pool
C1=parallel.pool.Constant(z);%%use parallel.pool.Constant to copy these variables into workers
U2=parallel.pool.Constant(up);
O2=parallel.pool.Constant(op);
for i=1:size(up,2)
f1(i) = parfeval(poolobj,@cores_random, 3, i, 1,C1,U2,O2); %%line 11
f2(i) = parfeval(poolobj,@cores_random, 3, i, 2,C1,U2,O2);
f3(i) = parfeval(poolobj,@cores_random, 3, i, 3,C1,U2,O2);
f4(i) = parfeval(poolobj,@cores_random, 3, i, 4,C1,U2,O2);
f5(i) = parfeval(poolobj,@cores_random, 3, i, 5,C1,U2,O2);
end
wait(f1,30000);
wait(f2,30000);
wait(f3,30000);
wait(f4,30000);
wait(f5,30000);
for j=1:size(up,2):-1:1
[idx1,u1,o1,ep1]=fetchNext(f1);
[idx2,u2,o2,ep2]=fetchNext(f2);
[idx3,u3,o3,ep3]=fetchNext(f3);
[idx4,u4,o4,ep4]=fetchNext(f4);
[idx5,u5,o5,ep5]=fetchNext(f5);
end
function [uu,oo,ep] = cores_random(i, zidx,C1,U2,O2)
up = U2.Value(i)
op = O2.Value(i);
z = C1.Value(zidx,:);
%%doing some calculations here
%%z is of size 1*1e3
%%up is scalar op is scalar
end

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