accumulate values in aftereach function

Hi all,

I would like to accumulate values that I collect in real time from a function that runs in the background.

For example

q = parallel.pool.DataQueue;
f1 = AfterEach(q, @afterFunc);
fut1 = parfeval(@genData, 0, q1)
function  genData(q1)
while true
    send(q1, randn)
end
end

Ideally I would be able to accumulate using persistent variable, but I understand persistant variables cannot be used in cunjunction with parfeval:

function afterfunc(x)
persistent y;
if isempty(y); y = []; end;
y = [ y, x];
plot(y); % for example
end

I know I could accumulate the values in the genData(q1) function, but then, after a few thousand iteration, I would be sending a very large vector and it would take longer (then desired) to send

Answer 1

[Raymond Norris]

Persistent variables should work. Try the following

q = parallel.pool.DataQueue;
q.afterEach(@afterFunc);
f = parfeval(@genData, 0, q);

function genData(q)
while true
    send(q, randn)
    pause(1)
end
end

function afterFunc(x)
persistent y
if isempty(y)
    y = [];
end
y = [y, x];
plot(y)
end

[dleal]

Hi Raymond, thanks for your answer. This is exactly what I needed.