Hello,

I try to use reap and sow to accumulated values during a calculation. It is recommended because it is said to be faster than AppenTo. However, I would like to utilize all my cpu cores by using parallelsubmit on various reap expressions with nested for and sow. It seems that this does not work properly. Please take a look at the following example:

end = 5
Reap[
 For[t = 0, t < end, t++,
  Sow[t]
  ]
 ]
WaitAll[%]

returns: {Null, {{0, 1, 2, 3, 4}}} -> Good

end = 5
ParallelSubmit[
 Reap[
  For[t = 0, t < end, t++,
   Sow[t]
   ]
  ]
 ]
WaitAll[%]

returns: {Null, {}} -> Bad

However, if I replace the end variable with its value like so:

ParallelSubmit[
 Reap[
  For[t = 0, t < 5, t++,
   Sow[t]
   ]
  ]
 ]
WaitAll[%]

returns: {Null, {{0, 1, 2, 3, 4}}} -> Good

Why is that?