performance - Matlab parfor, cannot run "due to the way P is used" -

i have quite time consuming task perform in loop. each iteration independent others figured out use parfor loop , benefit i7 core of machine.

the serial loop is:

 i=1 : size(datacoord,1)      %p matrix: person_number x z or     p(i,1) = datacoord(i,1); %pn     p(i,4) = datacoord(i,5); %or     p(i,3) = predict(barea2, datacoord(i,4)); %distance (z)      dist = round(p(i,3)); %round distance how many cells     x = ceil(datacoord(i,2) / (im_w / ncell(1,dist)));     p(i,2) = pos(dist, x); %x  end 

reading around parfor, doubt had use dist , x indexes calculated inside loop, heard problem. error matlab way p matrix used though. how it? if remember correcly parallel computing courses , interpret correcly parfor documentation, should work switching for parfor.

any input appreciated, thanks!

unfortunately, in parfor loop, 'sliced' variables such you'd p cannot indexed in multiple different ways. simplest solution build single row, , make single assignment p, this:

parfor i=1 : size(datacoord,1)      %p matrix: person_number x z or     p_tmp    = nan(1, 4);     p_tmp(1) = datacoord(i,1); %pn     p_tmp(4) = datacoord(i,5); %or     p_tmp(3) = predict(barea2, datacoord(i,4)); %distance (z)      dist = round(p_tmp(3)); %round distance how many cells     x = ceil(datacoord(i,2) / (im_w / ncell(1,dist)));     p_tmp(2) = pos(dist, x); %x     p(i, :) = p_tmp; end